PREPARED FOR:
Nestucca / Neskowin Watershed Council

PREPARED BY:
Steve Trask
Bio-Surveys,LLC.
Po Box 65
Alsea, Or.
97324

FUNDED BY:
Oregon Watershed Enhancement Board

RAPID BIO-ASSESSMENT 2003

INTRODUCTION

             A Rapid Bio-Assessment inventory was conducted for the Nestucca / Neskowin Watershed Council (NNWC) during the summer of 2003. This inventory included the Nestucca, Neskowin and Sand Lake basins. The intent of the project was to gather information on the status of juvenile salmonid summer distributions and summer rearing densities. The inventory consists of extensive snorkel surveys in each basin that begin at the head of tidal influence and continue to the end of juvenile Coho distribution in each stream and its tributaries (mainstem Nestucca begins at the confluence of Beaver Cr.).  These surveys were conducted using funds granted to the NNWC by OWEB.  The intent of these surveys is to develop base line data for each of three successive cohorts and to eventually identify long term trends in the distribution and abundance of juvenile Coho, Steelhead, Cutthroat and Chinook at the 6^th field level in response to restoration and watershed management issues.

            The escapement of adult Coho in all of the surveyed basins and ocean tributaries during the 2001and 2002 brood years has remained insufficient to adequately seed the summer habitat currently available on a watershed scale throughout the four 5^th fields in the NNWC management area. For many of the basins and subbasins, adult escapement is the primary limiting factor for production. The trend in the adult escapement of Oregon Coast Natural (OCN) Coho since 1990 has been positive for all of the NNWC basins with the highest recorded escapement in the last 13 years occurring in 2002. The Nestucca OCN Coho estimate for 2001 based on randomly selected adult spawning surveys was 3,940 and the Neskowin / Sand Lake estimate was 71. This figure more than tripled for 2002 rising to 13,068 while summer parr abundance almost doubled. The Neskowin / Sand Lake combined estimate for 2002 was only 16. These estimates exhibit dramatic increases in abundance and are indicators of recent improvements in ocean conditions. ODFW’s long term SRS monitoring of adult Coho escapement suggests that the 13 year trend for the North Coast monitoring area is one of only two statistically significant trends observed in the five coastal monitoring areas. This statistically significant trend was also detected in the more intensive monitoring associated with the Oregon Plan conducted between 1997 and 2001 (E-Map). Both methods suggest that the trend is driven primarily by abundance in the Nehalem River but that a significant positive trend is also quantifiable in the Nestucca.

It is important to recognize the significant role that changes in adult escapement can have on the observed distributions and densities of juvenile salmonids.  The resultant distribution data from 2003 still does not describe all of the accessible and suitable spawning and rearing habitats for salmonids because of continued under escapement.

            The survey method was designed to look at a sub sample (20%) of rearing habitats using a Rapid Assay technique that could cover large distances and succeed in describing the current distribution of Coho and quantify the rearing densities of Coho and the relative abundance of Cutthroat, Steelhead and Chinook in all of the surveyed streams and their tributaries.

            The database contains the results of 194 stream miles that were surveyed. This includes the full extent of Coho distribution in the Sand Lake (5.5 miles), Neskowin (10.6 miles) and Nestucca basins (146 miles) except for the segment of the mainstem Nestucca between the head of tidal influence and the confluence of Beaver Cr. and the majority of West Beaver (inadequate visibility). If a stream is not included in the database it was not surveyed. This will occur only in situations where a mapped tributary was dry or where there was a lack of suitable visibility for the survey methodology.

METHODS

            The basins and sub-basins surveyed were selected and prioritized by ODFW, BLM, USFS and NNWC technical advisors.  Survey crews were concentrated within a basin to complete the sampling activity within a concise window of time.  This approach led to transportation efficiency and eliminated any possibility of population shifts in response to changes in flow or temperature. This strategy was altered for the mainstem Nestucca where local knowledge from the technical advisory panel of the NNWC indicated that visibility in the lower mainstem could degrade during the summer months because of temperature driven algal blooms. This resulted in a hiatus of 24 days between surveys on the mainstem Nestucca between the first 10.7 miles surveyed in June above the confluence of Beaver Cr. and the remaining 22.2 miles surveyed in July and August to the end of Coho distribution. This hiatus was a replicate of the methodology utilized in year 1 of the RBA inventory to retain consistency in the methodology.

            Land owner contacts were made for all of the private, industrial and public ownerships that existed on both sides of every stream reach surveyed.  Developing these contacts involved extensive research in the county tax assessor’s office and then a personal contact to describe the survey and request permission for access. The land owner information was recorded (name, contact #, tax lot # and location) and will be available in subsequent years as a byproduct of this contract.

            Most surveys were initiated by randomly selecting any one of the first five pools encountered.  The protocol however was altered for small tributaries (2^nd order) where Coho presence or absence was undetermined, in these tributaries, the first pool above the confluence was selected as unit number one. This alteration in protocol was adopted to identify minor upstream temperature dependant migrations that may not have extended more than a few hundred feet. The identification of this type of migratory pattern in juvenile salmonids is critical for understanding potential limiting factors within the basin (temperature, passage, etc.). Some surveys were initiated at a point above brackish water influence or above agricultural influence where visibility conditions shifted from poor to good. In these surveys the start point of the survey will be indicated separately on the USGS quads available through the NNWC.

            The survey continued sampling at a 20% frequency (every fifth pool) until at least two units without Coho were observed.  In addition, pools that were perceived by the surveyor as having good rearing potential (beaver ponds, complex pools, tributary junctions) were selected as supplemental sample units to insure that the best habitat was not excluded with the random 20 percent sample. This method suggests that the data existing in the database could tend to overestimate average rearing density if these non-random units were not removed prior to a data query (the selected units are flagged as non-random in the database).

In subbasins with low rearing densities, there were situations where Coho were not detected for more than two sampled units.  These situations were left to the surveyors discretion, whether to continue or terminate the survey. There is a possibility that very minor, isolated populations of juvenile Coho could be overlooked in head water reaches of small 2^nd order tributaries. This tributary would have to include a strong beaver population that would impound emergent fry and truncate their normal downstream fry distribution patterns.

            Pools had to meet minimum criteria of being at least as long as the average stream width. They also had to exhibit a scour element (this factor eliminates most glide habitats) and a hydraulic control at the downstream end. There were no minimum criteria established for depth.  Only main channel pools were sampled.  Side channel pools, back waters and alcoves were not incorporated into the surveyed pool habitats. The primary reasons for not including these secondary and off channel pools is that they are typically not highly productive summer rearing locations and they compromise the consistency of measuring, summarizing and reporting lineal stream distances.

            The lineal distances represented in the database were estimated by pacing from the beginning of one sampled unit to the beginning of the next sampled unit.  The length of the sampled pool is an independent quantity, which was always measured and not estimated.  A minimum of three lineal estimates were also measured with a hip chain for each surveyed stream to develop a calibration factor for each surveyors estimate of distance.  Total distances represented in the database are consistently greater than map wheeled distances using USGS 1:24,000 series maps. This is related to the level of sinuosity within the floodplain that is not incorporated in mapping. If you are attempting to overlay this database on existing stream layer information there would be a need to justify lineal distances with known tributary junctions (these can be found in the comments column). In addition, the USFS under contract to the NNWC will be producing a digitized stream layer of Coho distribution for incorporation into the current GIS database.

Pool widths were generally estimated.  Because pool widths vary significantly within a single unit, a visual estimate of the average width was considered adequate.  Pool widths were typically measured at intervals throughout the survey to calibrate the surveyor’s ability to judge distance.

            The snorkeler entered the pool from the downstream end and proceeded to the transition from pool to riffle at the head of the pool.  In pools with large numbers of juveniles of different species, multiple passes were completed to enumerate by species. (Coho first pass, 0+ trout second pass, etc. ). This allowed the surveyor to concentrate on a single species and is important to the collection of an accurate value. In addition, older age class Steelhead and Cutthroat were often easier to enumerate on the second pass because they were concentrating on locating food items stirred up during the surveyors first pass and appeared to have less of their initial avoidance behavior.

            In large order stream corridors (mainstem Nestucca), two snorkelers surveyed parallel to each other, splitting the difference to the center from each bank.

            A cover/complexity rating was attributed to each pool sampled. This rating was an attempt to qualify the habitat sampled within the reach. The 1 - 5 rating is based on the abundance of multiple cover components within a sampled unit (wood, large substrate, undercut bank, overhanging vegetation). Excessive depth (>3 ft) was not considered a significant cover component. The following criteria were utilized:

1          0 cover present

2          1-25   %   of the pool surface area is associated with cover

3          26-50 %   of the pool surface area is associated with cover

4          51-75 %   of the pool surface area is associated with cover

5          > 75   %   of the pool surface area is associated with cover

            A point to consider here is that the frequency of higher complexity pools increases with a decrease in stream order. This inverse relationship is primarily a function of average channel width and the resultant ability of narrow channels to retain higher densities of migratory wood. Channel morphology begins to play a much more significant role in this relationship during winter flow regimes where increases in floodplain interaction and the abundance of low velocity habitat may become as significant as wood complexity.

A numerical rating was given to each sampled unit for the surveyor’s estimate of visibility. The following criteria were utilized:

Visibility                                                                

1          excellent                                                    

2          moderate                                                   

3          poor                                                           

            This variable delivers a measure of confidence to the collected data. Survey segments with a measure of 1 can assume normal probabilities of detection (the observed is within 20 percent of the actual for Coho). Segments with a measure of 2 suggest that less confidence can be applied to the observed number (uncalibrated) and segments with a visibility rating of 3 suggest that the observation can probably be used for only an assessment of presence or absence.

            There was also commentary recorded within each of the surveyed reaches that included information on temperature, tributary junctions, culvert function, the abundance of other species and adjacent land use. This commentary is included in only the raw Access database under the “comments” field and not in the Excel cd.

            The database contains fields designed to facilitate the development of a GIS data layer. These are LLID location numbers that are unique for each stream segment and latitude and longitude coordinates collected for unique features. Lat / Long coordinates are reported in degrees, minutes and seconds. Latitude and longitude values were not collected for start points because these values already exist in the actual LLID number used to initiate a surveyed reach.

            Latitude and longitude values were collected with a “Garmin 2 plus” GPS receiver with an external antenna. Many end point determinations were not verified with GPS coordinates because of the lack of reception.

 GENERAL OBSERVATIONS

The distribution and abundance of Coho juveniles observed during the 2003 summer field season was the result of a wide spread increase in adult escapement during the 2002 brood year. Estimates of adult escapement for the 2002 brood in the Nestucca exhibited a large increase (232%) from the previous year (ODFW SRS estimate) which resulted in a 92% basin wide increase in the 2003 summer rearing population of Coho. In addition, distribution of summer Coho parr in the basin was expanded by approximately 12 miles from the previous year. Summer parr estimates for the Neskowin basin improved by 36 % and decreased by 29% in the Sand Lake basin. ODFW adult estimates for these two basins were combined and indicated a 78% decrease in adult abundance for the 2002 brood.

Most habitats are still not seeded to capacity in the inventoried systems and there remains extensive summer habitat available to salmonids that are currently under utilized. There were some exceptions, Baxter, Bear, East Beaver, Elk, Louie, Sourgrass, and Trib B of the Nestucca exhibited a fully seeded condition for Coho during both the 2002 and 2003 inventories. These tributaries represent important anchor habitats for OCN Coho. For the following review, we are considering 1.5 fish / sq.meter a fully seeded density for Coho. There are concerns from many biologists that this estimate of fully seeded does not represent the production potential that exists in completely functional Coho habitat that is benefiting from the nutrient loading of adult spawning salmonids (eggs, carcasses). There are excellent examples in Elk Cr., Baxter Cr., and East Beaver Cr. of stream reaches that far exceed the level of 1.5 fish/sq.meter of pool surface area. The intent of establishing this target of full seeding is to provide a platform for comparing stream reaches to each other and to themselves over time. The graphics available in the Nestucca / Neskowin cd utilize this value to normalize scaling.

            The average density for a surveyed reach is an excellent measure of trend that can be monitored from year to year. However, it tends to portray only a general description of the current status within a reach. Understanding how each reach is functioning is more accurately interpreted in a review of how the rearing density changes within the reach. The graphics provided in electronic format with this summary are essential for the proper interpretation of this review (refer to 2003 Nestucca / Neskowin cd, NNWC).

Distribution profiles

            The distribution of juveniles and their observed rearing densities for each surveyed reach provide a basis for understanding how each reach is functioning in relation to the remainder of the basin or subbasin. These profiles can help identify spawning locations, identify potential barriers to upstream adult and juvenile migration, identify the end point of Coho distribution and they may also indicate how juvenile salmonid populations are responding to environmental variables such as increased temperature. You will find a review of these distribution profiles within this document for each of the major basins and subbasins surveyed during the 2003 field season. Trend analysis will become an important aspect of this review upon completion of the 2004 inventory, concluding three continuous years of monitoring.

Location of spawning destinations

The approximate locations of spawning pairs was observable in many of the sampled sub basins by the presence of a distinct spike in rearing density that trailed off rapidly just upstream. The physical location of a spawning destination has a range of variance plus or minus 4 pools due to the 20 percent sample methodology.  Depending on the average distance between pools, this typically describes a maximum lineal distance that varies between 150 ft. in a small 2nd order tributary to 800 ft. in a fourth order tributary. To utilize the database to identify spawning destinations, an additional precaution is necessary. Surveyed lineal distances are typically longer than calculated distances (map wheel, GIS, etc.) due to the sinuosity of the active channel that is not displayed in the 1:24,000 series USGS maps. To accurately evaluate site specific locations it is important to utilize the digitized map layer that has been justified to known end points and tributary junctions. This layer is currently being developed by the USFS and is available from the Nestucca / Neskowin Watersheds Council.

            The average densities generated represent a snapshot in time of the current condition that can be compared to known levels of abundance that exist in fully seeded and fully functional Coho habitats. These densities also provide a method for quantifying changes in rearing densities by reach or subbasin over time. Average densities utilized as a metric in this analysis are calculated for pool surface areas only. Lower levels of Coho abundance exist in fast water (riffle/rapid) and glide habitats. Replicate surveys conducted in these same reaches in subsequent years will function as an indicator of response to future restoration and enhancement strategies and potential changes in land use. It does not however, provide any indication of actual smolt production because of the distinct relationship between juvenile Coho survival and the abundance of high quality winter habitat.

Adult and Juvenile Barriers

                Adult migration barriers are verified by determining that no juvenile production is occurring above a given obstruction (culvert, falls, debris jam, beaver dam, etc.). There are many barriers, both natural and manmade that impact the migration of salmonids in coastal basins. Some are definitive barriers that are obvious obstructions (such as the bedrock falls on the Little Nestucca below the confluence of Fall Cr.). Many barriers however, only impede adult salmonid migrations during low flow regimes. Summer juvenile inventories allow us to definitively quantify whether passage was obtained at any point during the season of adult migration.

            Juvenile salmonids typically migrate upstream for a variety of reasons (temperature, winter hydraulic refuge, food resources). Hydraulic refuge and food resources are typically fall, winter and spring migrations that would not be detectable during summer population inventories. Temperature however, is probably the most significant driver of upstream juvenile salmonid migrations during summer flow regimes. Juvenile barriers are subjective to the eye of the observer. The trend in juvenile density can be a method of detecting either partial or full barriers to upstream migration. Each of the surveyed reaches contains a comments section in the Access database to note the presence of culverts, jams and other physical factors that may influence the ability of salmonid populations to make full use of aquatic corridors.

 Temperature Dependant Migrations

 Potential temperature dependant migrations can be observed in the database by looking for densities that decrease significantly as the lineal distance increases from the mouth of the stream or tributary. This is more likely to be observed in the case of low abundance years where tributary habitats that are seeded to capacity are the exception. During years of high abundance there is a more significant potential for density dependant upstream migrations that would be indistinguishable from the distribution pattern mentioned above. The recognition of this migration pattern allows us, during years of low escapement, to identify important sources of high water quality within the basin that may be traditionally overlooked because of some other morphological condition that suggests to us that there is no significant potential for rearing salmonids (i.e. lack of spawning gravel). These stream reaches typically exhibit declining densities with increased distance from the mouth and no indication of a spawning peak (a point near the upper distribution of the population with significantly higher rearing densities). These tributaries may be functioning as important summer refugia for salmonid juveniles threatened by increasing temperatures in the mainstems.

Precautions

            The specific location of spawning sites does not infer that the highest quality spawning gravels were targeted by adult salmonids or that there is any relationship between the location of a redd and the quality of the rearing habitat that exists adjacent to these locations.

            The location and distribution of juvenile Coho represented in the database is not related to the quality of the rearing habitat that exists in the aquatic corridor adjacent to these sites.

            The average densities that can be generated as an end product for each stream reach are the result of a 20 percent sample. Consequently, they probably vary significantly around the true average density. There are many sources of potential variation, start point, number of units sampled within the reach, surveyor variability, etc. The range of variability for at least one of these variables (start point), was documented in the final review of the 1998 Rapid Bio-Assessment conducted by Bio-Surveys for the Midcoast Watershed Council. To facilitate the proper utilization of the data included in this inventory, the 1998 results are included in Table 1. The true average density of a stream reach was retrieved by querying the database from an ODFW survey on East Fk. Lobster where every pool was sampled. Comparisons could then be made between the true average density and a randomly selected 20 percent sub sample (every 5th pool). Only mainstem pools were utilized within the range of Coho distribution to match the protocol for the Rapid Bio-Assessment. Table 1 contains this comparison, exhibiting the variation in average density based on the selection of different starting points.

(Table 1)

SAMPLE FREQUENCY     AVG. COHO DENSITY               AVG. SH DENSITY    AVG. CUT DENSITY    AVG. 0+ DENSITY

100 %                             1.07                                     .03                             .04                        .13          50                                  1.10                                      .04                             .03                        .14

20 % Start Pool 1             0.87                                      .04                             .03                        .13

20 % Start Pool 3             1.01                                      .03                             .03                        .13

20 % Start Pool 5             1.13                                      .05                             .04                        .12

                When calculating the average density of juvenile Coho in a particular stream reach, it is important that only the data be utilized that falls within the distribution of Coho. Many stream reaches contain sample sites that extend well above the actual distribution of juvenile Coho. Including these data points significantly underestimates the average rearing density and provides a poor foundation for monitoring trends in subsequent years. There are also many streams surveyed that have a downstream point of Coho distribution that is well above the start of the survey reach. Two factors for each stream reach surveyed are key elements for trend analysis, the extent of the distribution and the average density within that distribution.

SITE SPECIFIC OBSERVATIONS 

Site specific observations within this document have been organized in a format that utilizes GIS definitions to describe basins and subbasins. The area within the NNWC management zone includes four 5^th fields. Each of these 5^th fields has been summarized separately. The expanded juvenile salmonid estimates are also broken down into 5^th field estimates (i.e., the mainstem Nestucca does not include the production from the Little Nestucca).

Nestucca

The Nestucca mainstem was not surveyed below the confluence of Beaver Cr. because of compromised visibility resulting from suspended solids and algae. There is significant juvenile salmonid rearing that occurs in these 14.5 river miles between Pacific City and the confluence of Beaver Cr. (6.6 of these river miles are classified as intertidal, from the boat ramp in Pacific City to the head of tide at the Cloverdale bridge). This potential production has not been accounted for in the 4^th or 5^th field production estimates below.

The following tables represent the contribution in salmonid production (by species) from each tributary to the Nestucca 4^th field Watershed.  Table 2 represents results from 2003 inventories and Table 3 represents production within just the Main Nestucca 5^th field (minus the Little Nestucca subbasin). These production estimates are based on an expansion of the 20% snorkel sample in pools only and therefore do not constitute an entire production estimate for the basin. These estimates  greatly under estimate the standing crop of 0+, Steelhead and Cutthroat because a large component of the basins standing crop is summer rearing in riffle / rapid and glide habitats that were not inventoried. In addition, there is also production for these three groups that extends upstream beyond the end point of Coho distribution where the surveys were terminated. This table however, can be utilized to establish a baseline for trend monitoring for subsequent survey years on the basin wide scale and by tributary. The table functions well to establish relative production potentials that can be utilized as a foundation for prioritizing restoration opportunities.

Basin wide Coho production rose 92% in 2003 in response to the surge in adult escapement. The top five subbasins changed little from the previous year except for Moon Cr. taking the place of Bear Cr./Nestucca as #5. Improvements were seen in almost every subbasin and many small tributaries which had no Coho populations in 2002 were found with small numbers of rearing juveniles. Highest rearing increases were found in Powder Cr. (798%), Moon Cr. (533%), Little Nestucca Mainstem (327%), Niagra Cr. (265%), Mainstem Nestucca (91%), Three Rivers (70%), Elk Cr. (58%), and Bear Cr./Nestucca (40%). The only decreases were observed in the Louie Cr. subbasin of the Little Nestucca. Habitat reaches seeded to capacity were found in Elk Cr., Bear Cr./Nestucca, East Beaver Cr., and Baxter Cr.

Overall Steelhead production within surveyed reaches dropped by 11% in 2003. Increases were observed in Bear Cr./Nestucca (53%) and the Little Nestucca subbasin (26%) while the largest reduction in abundance was recorded in Moon Cr. (-44%), Mainstem Nestucca (-26%), and East Beaver Cr. (-18%). The top five subbasins for Steelhead production remained the same though their order has been somewhat shuffled. A dramatic 44% decline was noticed in 0+trout abundance during this year’s survey, mostly within the Nestucca mainstem and its upper tributaries. Based on this data, continued declines in 1+Steelhead and Cutthroat are expected in 2004 inventories.

(Table 2) 2003 INVENTORY

* Highlighted estimates represent the top 5 producers by species and age class for 2003

(1) % contributions are indicated for only those subbasins that contributed greater than 1% of the total.

(2) The Beaver Cr. estimates do not include the additional production available in West Beaver because of the lack of visibility for conducting the snorkel inventory.

(Table 3)

Expanded Nestucca (5^th field) Estimates of Juvenile Salmonid Production

Survey Year            Coho                 0+             Sthd                Cut

2002                      159,495         126,400        24,120            20,615

2003                      301,440           66,090        20,900            16,550

The table above deletes the production occurring in the Little Nestucca and facilitates a review by 5^th field.          

Mainstem Nestucca

(Table 4)

Expanded Mainstem Nestucca  Estimates of Juvenile Salmonid Production and Contribution to the 5^th field

Survey Year              Coho                      0+                        Sthd                     Cut

2002                     82,395 (52%)      36,700 (29%)        8,185 (34%)*       5,685 (28%)*

2003                   157,425 (52%)      20,585 (31%)        6,050 (29%)*       4,095 (25%)*

* The 5^th field percent contributions would be significantly higher if the rearing occurring in the

lower 14 miles of mainstem were included.

            The Nestucca mainstem from the confluence of Beaver Cr. to the end of Coho distribution at the confluence of Cedar Cr. was again the single most productive component of the entire 5^th field for all species of juvenile salmonids. 2003 Coho abundance in this reach nearly doubled from 2002 estimates. This mainstem population was 151% larger than the production from the entire Little Nestucca basin. This segment of mainstem rearing habitat encompassed approximately 33 lineal miles and exhibited by far the greatest production potential in the 5^th field. Many of the smaller order tributaries that contribute flow to the mainstem truncate fish distribution with definitive anadromous barriers, steep gradients or elevated summer temperatures. The maintenance of the water quality (summer flows, temperature, DO) in the mainstem is therefore paramount to preserving and optimizing the production potential of the system as a whole because of the vast abundance of habitat it provides. Because diminishing water quality has been identified in the NNWC Watershed Assessment of 1998 as a primary issue in the management and restoration of the basin, it is important to understand that for salmonids to flourish on a scale that mimics historical conditions, the final goal is to attain quantifiable improvements in mainstem water quality parameters (see recommendations).

            The distribution of summer rearing Coho juveniles during the 2003 inventory remained similar to that observed in 2002.  Most production appears to be concentrated above the confluence of Boulder Cr. and below the confluence of Elk Cr.  High counts continued this year for an additional two miles above Elk Cr. There was a distinct transition in water quality observed below the confluence of Boulder Cr. Sticklebacks appeared in the mainstem inventory at this junction, the level of suspended particulates in the water column increased, and algal growth was distinctly more abundant on substrates. Coho densities dropped off through this zone and are believed to continue to decrease further downstream. Peak Coho numbers occurred just above the confluence of Niagra Cr. This year’s results display a productive corridor of approximately 27.5 miles in length from Boulder Cr. to the end of distribution at Cedar Cr., a 9 mile increase in substantial production compared to 2002.  Some of the mainstem pools in this reach were summer rearing over 1,600 Coho juveniles each. The average rearing density for all mainstem pool habitats increased from 0.15 Coho/sq.m in 2002 to 0.52 Coho/sq.m in 2003 with a peak density of 1.6 Coho/sq.m. Coho were relying heavily on the shallow cobble margins in the absence of complex wood. In habitats with some level of wood roughness densities were double the adjacent pools with none. Indications are that wood complexity is a very important component of even summer habitats in these large stream corridors for providing protection from predation. Mainstem juvenile densities above the confluence of Elk Cr. remain high, indicating that the mainstem spawning of adult Coho in this reach is significant. 

            Steelhead distribution was distinctly different than observed for Coho with peak numbers occurring lower in the surveyed section and dropping off rapidly above survey mile 13 (just below Niagara Cr.). This contrast in distribution is identical to the pattern observed in 2002 for Steelhead, Cutthroat, and Chinook juveniles. Because of the increasing size of the pool surface areas progressing downstream from the headwaters the lower densities of Steelhead observed actually resulted in higher production. There were no pools above the 13 mile mark (from the confluence of Beaver Cr.) with more than 10 Steelhead observed. In comparison, many pools just above the confluence of Beaver were rearing between 40 and 60 older age class Steelhead. This year’s inventory exhibited much lower abundances throughout the upper mainstem reaches compared to 2002 when high counts extended up to survey mile 26. This year’s inventory also revealed a 26% decline in total 1+Steelhead numbers throughout the mainstem survey, along with similar declines in 0+trout, Cutthroat, and juvenile Chinook. The 44% drop in 0+trout abundance stands out as the most dramatic change among these species and seems to suggest further declines in 1+trout abundances for 2004 inventories. The obvious long term concern is for the declining trend in the abundance of adult steelhead.

Indications are that large numbers of Steelhead may be summer rearing in the mainstem well below the confluence of Beaver Cr. with a steady decline in the number/pool as the distance increases above the confluence of Beaver. The methodology employed during these snorkel inventories only portrays a picture of pool habitats and even larger numbers of Steelhead juveniles were present in each riffle and rapid habitat type. The significant observation here is the increasing importance of the mainstem for summer Steelhead rearing in a lineal progression downstream from the headwaters. Because the survey did not include the mainstem below the confluence of Beaver it was not possible to assess whether this trend of increasing abundance would have continued below the confluence of Beaver Cr.

            Cutthroat distribution very nearly mimicked the pattern observed for Steelhead with a steady decrease in abundance observed with the lineal progression above the confluence of Beaver Cr. Cutthroat populations declined 28% throughout the mainstem survey reach in 2003. Very large (18 inch) Cutthroat were common in this lower mainstem. They were closely associated with concentrations of juvenile Chinook and were preying heavily on these salmonids (distended stomachs and stalking behavior). The distribution of these older age class Cutthroats may be closely linked with the seasonal distribution of Chinook fry in their steady progression towards the estuary. The close resemblance between both 2002 and 2003 trout and juvenile Chinook distribution patterns continues to support this hypothesis. 

There was an expanded estimate of 43,040 juvenile Chinook observed in the inventory above the confluence of Beaver Cr., a 34% decrease in abundance from 2002. Their distribution closely matched the same pattern seen in Steelhead and Cutthroat with decreasing abundance above the confluence of Beaver Cr.  Most juvenile Chinook were observed below the confluence of Niagara Cr. and none were seen above the confluence of Elk Cr., a reduction of 3 miles in distribution from the previous year. The changes in juvenile Chinook abundance may be insignificant because of their life history pattern that has them programmed to steadily migrate toward the estuary. A mainstem survey 2 weeks later would likely observe a decline in abundance. Adult Spring Chinook, Summer Steelhead, and Chum Salmon were observed also within the mainstem inventory.

Bays

            Bays Cr. exhibited a dramatic increase of 573% in its summer rearing Coho population in 2003.  Expanded summer rearing estimates for Coho parr rose from 395 to 2,660 and average rearing density rose from 0.1 Coho/sq.meter to 0.7 Coho/sq. meter.  A peak density of 2.1 Coho/sq.meter was observed at RM 1.7. Distribution increased by 0.5 miles to reach 2.5 miles total. There were Steelhead also present rearing in the subbasin that were broadly distributed, their abundance indicated no change from the previous year.

Bear

            Bear Cr. exhibited an expanded summer rearing estimate for Coho of 12,780, an increase of 40% from 2002. Their average rearing density of 1.4 fish/sq.meter showed little change, probably due to an increase in distribution of 0.6 miles to a total of 3.2 miles.  There were two observed zones of peak spawning activity where rearing densities rose well above full seeding. They were separated by a steep boulder incline and narrow bedrock gorge at RM 1. The lower zone appears more heavily used and Coho rearing densities here peaked over 3.0 Coho/sq. meter.  66% of Bear Creek’s Coho were observed in this first mile. Above the narrow gorge a large supply of fine gravels and sand is retained and nearly 2 miles of excellent floodplain interaction exists. An older stand of conifer is present along much of the left side of the canyon. Rearing densities in this upper reach peaked just over 2.0 Coho/sq. meter at RM 2.1. This data suggests that Bear Cr. as a whole was nearly seeded to capacity. Bear Cr. and neighboring Elk Cr. appear to be key anchor habitats for Coho in the mainstem Nestucca. Coho distribution in Bear Cr. ends in a long stretch of bedrock above several large debris jams.

            1+Steelhead populations rose 53% this year in Bear Cr. to reach a total expanded estimate of 1,095.  Their abundance appeared to increase with distance above the bedrock gorge. A mild occurrence of spotty white mucous was noted on most 1+Steelhead in Bear Cr. A radical decline in 0+trout was noticed this year in Bear Cr. with expanded estimates dropping from 11,810 to just 3,300.

Beaver

            East Fk. Beaver is listed in the NNWC Assessment as exceeding the DEQ standards for summer water temperature. The West Fk. of Beaver remains below the minimum standard for temperature listing. The West Fk. of Beaver was not surveyed in 2002 or 2003 due to poor visibility. This included Tiger Cr., NF West Beaver and Trib A. The surveyor’s notes from 2002 indicate that juvenile salmonids were present and abundant (observations were common of fish disturbing the surface). This condition is believed to be caused by the extensive dunal forest habitats to the west which are drained by these tributaries. This is a unique geology within the Nestucca Basin and closely resembles conditions in the nearby Sand lake basin. The Access database treats the Beaver Cr. subbasin different that most other basins. By following the USGS naming protocols established on the 1:24,000 scale, Beaver Cr. terminates at the junction of West and East Beaver. To completely understand the current distribution profile of juvenile salmonids in the subbasin, the user will need to append the East Fk. data to the top end of the Beaver Cr. data set.

Beaver Cr. is a major producer for Coho. By comparison, Beaver Cr. alone produced Coho at a level equal to 51% of the entire Little Nestucca subbasin and supported a level of production that was 20% of the mainstem Nestucca total. In addition, an expanded estimate of 3,480 1+Steelhead in the subbasin represents 58% of the mainstem Nestucca totals.

            For the mainstem of Beaver Cr. from it’s confluence with the mainstem Nestucca to the confluence of the East and West Fk. (3.0 miles) there was an expanded estimate of 1,930 summer rearing Coho parr (6% of subbasin production). This figure has fallen 34% from last year’s total while Coho production in the East Fork has increased by 21%. In addition, this section of Beaver had an expanded estimate of 1,140 Steelhead (33% of the subbasin total) in 2003. This figure fell 18% from 2002 estimates. It should be noted that poor visibility near a bridge under construction could have accounted for some portion of these reductions. 1+Steelhead counts in East Beaver fell 8%. Large stretches of cobble and boulder glides found in this subbasin were probably rearing high numbers of 1+Steelhead and were not a part of this inventory. However, trends based on an identical survey methodology from last year should still be regarded as meaningful. Distribution patterns for all species indicate that Beaver Cr. is not being utilized as upstream temperature refugia from the mainstem. This tracks well with the temperature data that suggests elevated stream temperatures may be a factor limiting water quality in Beaver Cr.

            East Fk. Beaver and its tributaries were producing an estimated 30,180 Coho in 2003, 94% of the total Coho observed (understanding that the West Fk. was not surveyed) in the Beaver Cr. subbasin (up 89% from last year). Average rearing density increased to 1.5 Coho/sq.m. and the distribution decreased by 0.8 miles to a total of 10.2 miles from the confluence of mainstem Beaver. 2002 rearing densities increased from beginning to end of survey indicating a narrow (2.3 mile) distribution of adult spawners between RM 7.2 and 9.5. This zone expanded to 3 miles in 2003 with a few pools exhibiting rearing densities over 5 Coho/sq.meter. In addition, a second zone of spawning activity was centered around RM 4.  This reach also covered approximately 3 miles and with rearing densities over 2.5 Coho/sq.meter. Pool surface areas were considerably higher in this lower zone and the larger abundance here accounted for 47% of East Beaver’s summer Coho production. It would appear that Coho production is near capacity levels. The larger pool surface areas just above the confluence with mainstem Beaver also retained the majority of the subbasins production of Steelhead and Cutthroat. This distribution is identical to last year’s observations for these species. A potential parasitic infestation (resulting in spots of white mucous on the dorsal surface) was noted on most 1+Steelhead. Juvenile Chinook distribution ended by RM 3.3. No Access was granted by landowners between RM 1.3 and RM 2.5, therefore a portion of each species’ production has not been quantified for the subbasin (mileage was included in distribution graphics). A distinct lack of in-stream wood and streamside cover was noted throughout East Beaver until well into its upper reaches. Fish distribution ends in a series of steep boulder/debris jams.

Bear Cr. (0.5 miles) and Trib C (0.33 miles) appear to be the most important tributaries in the subbasin, contributing 1% and 2%, respectively, to total Coho production. Low flows and small pools limit distribution in Trib C. Access denial in Bear Cr. terminated survey efforts at approximately RM 1.6. Flows in Bear Cr. were significant and suitable habitat appeared to continue considerably further.  Density profiles suggest that Bear Cr. is providing important cold water temperature refuge for the mainstem of East Beaver.

Bible

            Bible Cr. contained Coho to a point 0.9 miles above the confluence with the mainstem where adult passage is terminated at a 30’ waterfall. The expanded summer rearing estimate for Coho rose dramatically from 365 last year to 2,340 in 2003. The 2002 average rearing density of 0.16 Coho/sq.m increased to 0.8 Coho/sq.m. Steelhead were also present.

Boulder

            Boulder has a number of stream crossings that all appear to be negotiable to both adult and juvenile salmonids. Coho distribution increased by 0.6 miles on the mainstem to reach 2.9 miles total. Rearing density averaged 0.4 Coho/sq.m. and the total summer rearing estimate increased by 232% to 1,860 juvenile Coho. 20% of this total was observed in 0.8 miles of Turpy Cr. This tributary appeared to exhibit temperature dependent upstream migration patterns. No Coho were observed here last year.  Turpy Cr. displayed a higher average rearing density of 0.66 Coho/sq.m.  Distribution in both creeks ended in steep boulders. Steelhead were also present in low numbers (245 expanded).

Cedar

            Cedar Cr. enters the mainstem very near the end point of Coho distribution in the mainstem Nestucca. Cedar contained only Coho that were upstream migrants from the mainstem seeking temperature refugia from the elevated stream temperatures in the upper mainstem. There is a boulder gorge in the mainstem that terminates adult Coho migrants just above the confluence of Cedar Cr. There are distinct water quality concerns in the headwater reaches that involve establishing a minimum summer flow for the Nestucca ecosystem and the current and quantifiable issue of elevated summer stream temperatures that are visible in the juvenile salmonid response in Cedar Cr. Cedar Cr. was contributing 30% of the mainstem flow at its confluence. There is a 5ft diameter culvert on the main Hwy with a 4ft. summer perch. This pipe is terminating upstream juvenile salmonid migrations that are very significant because of the poor water quality in the upper mainstem above the confluence of Cedar. Unfortunately the maintenance of this crossing would only result in an additional 500 ft. of accessible habitat because of a 20 ft falls just upstream that terminates all anadromous distribution. Cedar Cr. contained an expanded estimate of 545 Coho in 2002 and just 145 Coho in 2003. No Steelhead were observed in 2002 while 20 (expanded) were estimated to be present in 2003.

Clarence

            Steelhead and Coho were present to a narrow bedrock gorge at a point 0.4 miles above the hwy crossing. Coho production was minor with an expanded estimate of only 85 summer parr in 2002 and 305 summer parr in 2003. Coho from both years appear to be the progeny of spawning within Clarence Cr. There was a definitive anadromous barrier (bedrock / boulder falls) 0.88 miles above the highway crossing. The survey began at the hwy crossing because access was denied in the stream segment from the hwy to the mainstem Nestucca. The hwy culvert was passable for juveniles and adults.

Clear

            The Clear Cr. survey began at the Jenks rd. crossing because access was denied from this crossing downstream to the mainstem Nestucca. Coho production here rose dramatically from an estimated 140 summer parr (expanded) in 2002 to 1,505 summer parr (expanded) in 2003.  Distribution increased by 0.3 miles to reach 1.2 miles total above the Jenks rd. culvert (easy passage) and rearing density averaged 0.65 Coho/sq.m. Flows in Clear Cr. were noted as clear and cold and gravel supplies abundant both below and above a narrow boulder/debris gorge, which has been passable during both survey years. This data suggests that a much higher production potential for juvenile Coho could be realized from Clear Cr. The lower end of Clear Cr. would be extremely valuable distribution data if access could be sequestered because of the potential for significant upstream temperature dependant migrations of juveniles from the lower mainstem. 510 (expanded) 1+Steelhead were also observed within the survey reach.

Elk

            Elk Cr. contains very high rearing densities of Coho to the end point of anadromous distribution at RM 2.6 (large falls, definitive barrier). Expanded estimates for summer rearing Coho parr in 2002 totaling 14,970 were very large for such a short reach.  2003 inventories on 8/22/03 exhibited a 58% increase to 23,610 (expanded) juvenile Coho. Elk Cr. rearing densities averaged 3.0 Coho/sq.m.  Distribution profiles exhibit a steady rise in density toward the endpoint where a peak of 7.6 Coho/sq.m. was observed. The 3 Coho / sq.m level of abundance almost doubles the expected carrying capacity of the habitat based on ODFW’s Coho Habitat Model. What we expect to see above fully seeded conditions of 1.7 Coho/ sq.meter are density dependant migrations out of the system to reduce intraspecific competition for food and cover. The opposite was observed in Elk Cr.

            An earlier survey of Elk Cr was conducted on 6/3/03, 2 ½ months prior to the August survey (These surveys are differentiated in the data base as Elk and Elk 2). A comparison between these two surveys was designed to document the changes in tributary production over time. What we expected to see on this high abundance year was a decrease in the standing crop between the two surveys. We assumed heavy predation, attrition out of Elk Cr. from density dependant pressures and a reduction in system carrying capacity as juveniles increased in size throughout the summer would decrease both total abundance and reduce the average rearing density. Densities remained almost identical (2.8 to 3.0 Coho/sq.m.) and total abundance remained similar (21,985 and 23,365). The variation in these estimates is within the range of normal, considering the extremely high pool estimates where surveyor error is known to increase. Two key points are however extremely interesting. 1) Fish distribution was evenly spread throughout the first survey and very concentrated on the second survey toward the anadromous barrier at RM 2.6. 2) No significant loss to the tributary population was noted, which may indicate the presence of additional upstream temperature dependant migrants from the mainstem.

            The abundance and accessibility of cold water habitats available in Elk Cr. appear to be very attractive to Coho moving up and down the mainstem corridor. Coho rearing densities and total numbers dropped off throughout the lower pools during the period between the two surveys while steadily increasing in the upper pools. Rearing density in August peaked in the last pool against the falls barrier at 7.7 Coho/sq.m.

A similar shift appeared in 1+Steelhead and Cutthroat populations. Highest counts for these species in June were observed in the beginning of the survey, in late August they were observed in the upper end. This pattern suggests that similar environmental triggers may be affecting multiple species and age classes.

1+Steelhead and Cutthroat populations were moderate, considering the available prey, and similar during each survey – about 500 (expanded) for each species. An estimated 75% of all 1+Steelhead observed, displayed signs of skin infection due to an undetermined species of either parasite or bacteria. A mild occurrence was noted in neighboring Bear Cr. also.

    This 2.6 miles of Elk Cr. ranked 3^rd in Coho production for the entire 5^th field (behind mainstem Nestucca and Beaver Cr.) for both 2002 and 2003. The lower channel exhibits abundant boulders with little wood and gradually transitions to include finer gravels and debris jams. Several log structure sites were noted in the upper half that are continuing to function as high quality plunge pool habitats (summer) and trap mobile gravels.

Fan

            Coho juveniles extended to the culvert crossing at RM 0.3 and terminated. The surveyor described the culvert crossing as excellent placement and no barrier to juvenile distribution. The last Coho were however observed in the pool below the culvert during both survey years. The total expanded Coho estimate for the tributary in 2002 was 135, and in 2003 was 275, with decreasing densities as the survey progressed upstream. Indications are that Coho in Fan may be the result of upstream temperature dependant migrations from the mainstem.

Farmer

            Farmer Cr. was an excellent contributor of cold water to the mainstem Nestucca. There is probably significant temperature maintenance provided to the mainstem from this tributary. There is a 2 ft. concrete dam at RM 0.44 that may be terminating the upstream distribution of juvenile salmonids from the mainstem. This was apparent in the increasing trend of juvenile Coho counts up to their highest peak just below the dam. Expanded estimates for Coho in Farmer Cr. were not high, 295 (expanded) in 2002 and 945 (expanded) in 2003, with a mix of spawning and upstream migration from the mainstem taking place. The dam did not appear to influence 1+Steelhead migrants to any significant degree during 2003. Most 1+Steelhead displayed signs of skin/mucous infection. Coho were observed to a point 1.4 miles above the confluence with the mainstem Nestucca. Substrate conditions around the endpoint were ideally suited to Coho spawning and a large potential exists in this stream for production increases. Long stretches of bedrock leading up to the dam are probably discouraging adult spawners. There was a road culvert at RM 0.67 that had an 8 inch drop that also may have impacted upstream juvenile distribution. There was Japanese Knot weed observed along the stream corridor that could still be controlled (its abundance was limited).

Foland

            There was a total of 40 Coho (expanded estimate) observed in Foland Cr. in 2002. Their distribution was limited to the first 0.26 miles and they originated from upstream migrations from the mainstem. Surveys in 2003 found 1,200 (expanded) Coho juveniles present in a low average rearing density of 0.4 Coho/sq.m. Their distribution extended for 1.5 miles and utilized the beginning of a small tributary. It appears that spawning, in addition to upstream migration, may have occurred this year in Foland Cr. Low numbers of Steelhead were also present during both years, seeming to prefer the upper reach of the survey.

George

            There was an expanded summer rearing estimate of 60 Coho juveniles observed in 2002 and 145 in 2003. Based on density profiles, Coho from both years appear to be migrating upstream from the Nestucca mainstem. 350 feet of dry channel were observed at the start of the 2003 survey indicating an early termination date to this refuge. Steelheads were also observed.

Ginger

            The 2002 expanded estimate for summer Coho parr was 40 for the subbasin. This figure showed little change in 2003 – an estimated 30 (expanded) summer parr. There were no Steelhead observed rearing in Ginger Cr. during either year. Coho extended only 400 ft and were probably the result of an upstream temperature dependant migration. There was a 6 ft falls just below pool #5 that probably truncates anadromous distribution. In addition, the culvert at the mouth of Ginger has a 1 ft. vertical plunge that probably terminates juvenile migrations late in the season.

Horn

            Coho were broadly distributed in Horn to a point 4.4 miles above the head of tidal influence, 1.7 miles beyond last year’s endpoint. The expanded summer rearing estimate for Coho rose 88% to reach 2,910. The average rearing density was 0.3 fish/sq.m and the peak was 1.1 fish/sq.m. This peak density was achieved at the survey endpoint although most production, 87%, occurred below RM 2. At least three sites of spawning appeared to have occurred in Horn Cr. this year which indicates significant improvement compared to 2002 escapement. All the observed culverts were passable for both adults and juveniles. There was a significant increase in the abundance of 1+ Steelhead observed (215 expanded) in the 2003 survey, only 10 (expanded) were observed in 2002. The gravels were classified as abundant and the subbasin has much greater production potential than presently observed for Coho.

Limestone

            No Coho were present here in 2002. Surveys in 2003 revealed dramatic improvement in Coho escapement within the steep boulder habitat of this tributary. Coho distribution this year extended 2.2 miles in the mainstem and a total 0.6 miles up two side tributaries. Rearing density averaged 0.45 fish/sq.m. in the mainstem, 0.7 fish/sq.m. in Trib A, and 1.2 fish/sq.m. in Trib B. Spawning peaks appeared low in the mainstem, 2.2 fish/sq.m. at RM 0.25 and in Trib A, 2.0 fish/sq.m. at RM 0.15. Some temperature dependent migration appears to be occurring in both side tributaries. Expanded Coho estimates totaled 1,450 summer parr, less than 1% of the Nestucca basin total. 77% of the Limestone Cr. rearing Coho population was found in the mainstem. The mainstem culvert appears to be in good shape and the cement steps easily passable. Distribution ends in the mainstem and Trib B in large steep boulders while Trib A ends in a series of vertical bedrock waterfalls, 6 foot and 16 foot each. An expanded estimate of 20 1+Steelhead were observed in 2.2 miles of mainstem while 85 were observed in just 0.25 miles of Trib A.

Moon

            Moon Cr. enters the Nestucca near Blaine and contains the major fourth order tributary East Cr. This subbasin has been the site of extensive long term aquatic research and restoration conducted by the BLM and ODFW. The two streams were the site of a paired treatment and control study that evaluated the impacts of changes in winter habitat on smolt production. The historical abundance’s observed in the subbasin indicate that relatively insignificant adult escapement of Coho occurred during 2001. The expanded estimate for 2002 summer rearing Coho parr for the subbasin was just 3,140. However, Coho were distributed broadly during 2003 (4.7 miles in Moon and 5.4 miles in East) in moderate densities. There was a 537% increase during 2003 summer inventories to19,990 (expanded) summer parr. This figure still appears to be well below the production potential existing in the subbasin. The aquatic habitats available in Moon and its tributaries indicate that Coho abundance could be substantially larger at full adult seeding. Coho production in East Cr. appeared 6% higher than in Moon Cr. Average rearing densities in both forks were identical at 0.8 Coho/sq.m. Distribution in East Cr. increased by 0.6 miles this year while Moon Cr. lost 0.3 miles of distribution. Surveyor comments note that much of the wood complexity existing in upper Moon Cr. had migrated out of the system by summer 2003 and that an increase in exposed bedrock was observed.

Multiple peaks in spawning activity were noted in each fork. A gradually increasing density trend toward the end of distribution was observed in Moon Cr. where rearing density peaked at 3.9 Coho/sq.m. (RM 4.3). Highest rearing densities in East Cr. were observed between RM 2.5 and RM 3.7 where an average of 1.3 Coho/sq.m was maintained and a peak of 2.6 Coho/sq.m. was attained. Distribution in Moon Cr. was terminated by an impassable log jam while a more permanent bedrock gorge terminated distribution in East Cr. Coho production in Moon Cr. is presently limited by adult escapement.

Both Steelhead and Cutthroat production remained significant in this subbasin despite significant reductions from the previous years inventory (-44% and -47%). The majority of each species was found in the lowest two miles of each branch. A dramatic 64% reduction in 0+trout abundance was also observed this year in both Moon and East Cr. (-64%, -63%).

Niagra

            Niagra exhibits tremendous salmonid production potential with easy access to high quality spawning substrates for 4.3 miles in the mainstem to a potential barrier at a bedrock falls and another 2.1 miles in Beulah Cr. to a major fork where gradients become limiting. In 2002 Coho were only utilizing 2.4 miles of mainstem habitat and their distribution terminated just above the confluence of Pheasant Cr. Only 0.7 miles of Beulah Cr. exhibited summer Coho rearing during 2002.

In 2003 their distribution extended through the remaining 1.9 miles of mainstem habitat up to the falls. The expanded estimate of summer rearing Coho parr rose 207% to reach 15,185 in mainstem Niagra and the average rearing density increased from 0.44 fish/sq.meter to 1.1 fish/sq.m. 84% of the subbasins production for Coho occurred in the lower two miles where multiple spawning peaks were observed (up to 1.9 fish/sq.m.). A large population of upstream migrants from the mainstem Nestucca was also observed in the lowest pools. Steelhead were present in moderate numbers.

There appears to have been a spawning event both years in the lower few hundred feet of Pheasant Cr. and a log jam barrier just above this point currently terminates upstream distribution of adult Coho (Steelhead were observed above this jam). An average rearing density of 3.4 Coho/sq.m. was observed here, though only 560 (expanded) Coho were estimated.

Beulah Cr. exhibited two spawning peaks in 2003, the first at RM 0.6 (1.3 Coho/sq.m.) and the second at RM 1.4 (2.5 Coho/sq.m.). Rearing density averaged 0.9 Coho/sq.m. throughout 2.1 miles of distribution, an increase of 1.4 miles. Coho production in Beulah Cr. (2,290 expanded summer parr) rose 309% and accounted for 13% of the subbasin total. Steelhead were present in low numbers. Coho distribution in 2003 in the Niagra subbasin has extended to the end of productive habitat though rearing densities remain below capacity. Adult escapement remains the primary limiting factor.     

Powder

            Powder Cr. contained Coho that extended to a point 2.6 miles above the confluence with the mainstem. This represents an increase of 1.7 miles of distribution in the mainstem as well as an additional 0.6 miles in the Left Branch where no Coho were observed in 2002. Shueble and Dahl Fork contained no Coho for the second year. Expanded estimates of summer rearing parr increased by 798% in 2003 to 4,895. The average rearing density in the mainstem rose from 0.14 fish/sq.m. to 0.86 fish/sq.m. and averaged 0.7 fish/sq.m. in the Left Branch. Two peaks in spawning density were observed in the mainstem, the first at RM 1.1 (1.7 Coho/sq.m.) and the second at RM 1.8 (1.1 Coho/sq.m.). High numbers of upstream migrants from the mainstem Nestucca were seen in the lowest pools. Rearing density in the Left Branch peaked at the end of distribution at 1.4 Coho/sq.m. Coho production in the left branch accounted for 6% of the subbasin total. Coho distribution in the mainstem ends in a series of steep waterfalls and in low flows in the Left Branch. In spite of dramatic improvements in the system, rearing densities remain below capacity in Powder Cr. probably due to adult escapement. Steelhead were also present in the system in low numbers. There was a white mucous observed on both Steelhead and Cutthroat in the tributary that appeared similar to the infections sighted in several upper Nestucca tributaries (Elk, Bear).

Slickrock

            The survey continued to a 60 ft. bedrock falls classified as a definitive anadromous barrier at RM 1.0 . Coho distribution actually terminated 0.3 miles downstream of the falls at a series of 6ft. bedrock slides. The expanded summer rearing estimate for Coho of 1,825 showed little change from 2002. Average rearing density remained healthy at 1.2 fish/sq.m. White mucous was also commonly observed on 1+ and older Steelhead and Cutthroat juveniles which may indicate the presence of a parasitic infestation.

Smith

            The Smith Cr. survey began at a submerged culvert low on agricultural land but above the confluence with the mainstem Nestucca. This culvert was not a passage problem for juveniles or adults. The next culvert crossing at pool #7 was a 4 ft perched pipe that was 4 ft in diameter. Coho during both survey years have been observed in the pool below the culvert and no higher. The culvert remains a definitive barrier to the upstream temperature dependant migration of juveniles. There did not appear to be any evidence of a Coho spawning event in Smith and the observed Coho were likely migrants from the mainstem. The Coho were exceptionally large and benefiting from the nutrient rich aquatic environment. The surveyor’s assessment of the conditions above the culvert suggests that salmonids would benefit from improved access at this road crossing (gravels, increased gradient).

Testament

            Testament was a major producer of juvenile Coho during 2002 and 2003 inventories. The expanded summer rearing estimate for Coho was 5,535 in 2002 and showed little change at 5,910 in 2003. Average rearing density remained a high 1.3 fish/sq.m. (a level near full seeding within their distribution). Three peaks in spawning activity were present in 2003: RM 1.1 – 2.3 Coho/sq.m., RM 2.3 – 1.6 Coho/sq.m., and RM 3 – 2.0 Coho/sq.m. Coho extended to RM 3.4 and were stopped by a series of large wood jams. There was a 1300 ft. boulder gorge that began at RM 0.9 that maintained significantly lower densities of Coho and Steelhead. The Hwy culvert was in excellent condition and passable for all age classes. Steelhead distribution graphics from both years suggest that upstream temperature dependant migrations from the mainstem Nestucca may be occurring.

Three Rivers

Three Rivers contains an ODFW production facility at Cedar Cr. that raises Spring Chinook, Summer and Winter Steelhead. Because the location of this facility is low in the Three Rivers subbasin, there is a trap and fish weir in place to trap adults of hatchery origin that may be compromising the unimpeded upstream migration of wild anadromous migrants. It is important to understand that the current genetic selection, production potential, and distribution of OCN Coho, wild Winter Steelhead, wild Fall Chinook, and Sea run Cutthroat in the Three Rivers subbasin may be impacted by the hatchery practices occurring at the site of this weir. All anadromous populations exhibit broad run timing profiles that overlap with other species and subspecies. The peaks of these profiles typically differ but there is significant overlap in the early and late components of each of these runs. For the Cedar Cr. site, the weir is passable from the first significant fall freshet to a point when hatchery Winter Steelhead adults first appear. It is this line of demarcation between fall Chinook and winter Steelhead (variable from year to year and dependant on flow regimes) that may truncate the late spawning component of both the wild Fall Chinook and the late OCN Coho populations. The effect of this demarcation may be most significant for OCN Coho because the potential for adult spawner escapement exists in many coastal Coho systems into the month of February.

            Three Rivers exhibited only minor escapement for OCN wild Coho for the 2001 brood year. The expanded estimate of summer rearing Coho parr for the entire subbasin in 2002 was 995. The majority of these juveniles (77%) were observed in Alder Cr. with the only exception being the 35 (expanded) juveniles observed in Pollard Cr. and the 190 (expanded) observed in the mainstem (primarily below the confluence with Alder). Adult escapement for the 2002 brood year increased but remains insignificant compared to the abundance of potential rearing habitat. Expanded estimates for Coho experienced a 70% increase in 2003 to 1,695. This remains an extremely low figure in relation to the 17 miles of habitat available in the subbasin and stands out in the Nestucca Basin as its least productive reach. Densities in all reaches remained extremely low. The majority of the population (49%) remained in Alder Cr. with an additional 31% below the mainstem weir, 12% in the mainstem above the weir, and 8% in Crazy Cr. (where none were observed in 2002).

 Distribution in Alder Cr. extended for 3 miles and the highest counts occurred within the first mile where some spawning appears to have occurred. Coho end in a large brackish swamp above a long reach of straight boulder chutes adjacent to the highway, just before the final highway crossing. Some of the best habitat exists above this last culvert where gradients decrease, sinuosity is restored, and large supplies of fine gravel are present. The Buck Cr. tributary was vacant of Coho despite excellent habitat conditions. 72% of the Coho rearing in the mainstem were present in the two miles below the weir and above the confluence with the mainstem Nestucca. The densities were very low (averaging 0.04 fish/sq.m.). This component of Coho distribution was completely missing from the 2002 inventory which may suggest that these juveniles are the result of a spawning event and not the result of an upstream temperature dependant migration (temperature dependant movement would have likely been observed in both years and not just one). If this distribution pattern was the result of mainstem spawning, it could support the same condition referred to above (difficult passage for wild adults arriving after the weir is raised to retain winter steelhead). It is not impossible that Coho would elect to spawn below the weir but more common that they would continue to migrate to headwater spawning locations. The remaining 6.4 miles of mainstem Three Rivers distribution exhibited very few sightings and several long gaps in the summer rearing population. Conditions remain suitable for Coho spawning up to RM 9.4 where a 20 foot vertical waterfall presents a definitive anadromous barrier. The 0.33 miles of distribution in Crazy Cr. appears to be due to upstream migration. About three miles of suitable habitat in Lawrence Cr. and Pollard Cr. continues to go largely unutilized.

Based on equations calculated by Nickelson and Lawson (1998) the 2002 expanded juvenile Coho estimate for the Three Rivers subbasin represents an adult escapement of something on the order of 6-10 adults (assuming 1:1 male / female ratio), and the 2003 estimate represents approximately 10-17 adults. This limited production compared to the abundance of high quality habitat (approx. 17 miles) available for OCN Coho suggests that some of the greatest cost / benefit ratios for restoration exist in this subbasin for restoring proper watershed function and boosting OCN Coho production (see recommendations).      

Steelhead juveniles were present in densities similar to those observed in other subbasins, indicating that normal escapement is occurring. Densities appeared to show little change around the site of the weir and 49% of the subbasin population was found in the lowest 5 miles of the mainstem. The concerns for Steelhead are two fold; does the present escapement represent the diversity that exists in run timing and what are the genetic origins of the adults passed at the Cedar Cr. weir (hatchery / wild interactions). Observations of external mucous on Steelhead juveniles was common, with individuals exhibiting less than 10% impact on body surface area in most reaches. Some individuals sighted in Crazy Cr. displayed 50% coverage. This mucous is probably a response to external parasites (sp. undetermined). Mucous observations occurred both above and below the Cedar Cr. weir.

Cutthroat were present throughout the subbasin. The higher densities observed were often located in close proximity to the highest densities observed for Coho juveniles – the lower reaches of the mainstem and the lowest mile of Alder Cr. This relationship was observed in last year’s distribution pattern also and is an indication of the value of anadromous salmonids to resident populations.

There were Chinook juveniles observed in the mainstem of Three Rivers up to RM 8.1. Densities peaked around the site of the weir and decreased upstream. Expanded estimates in 2003 of 3,195 juveniles exhibited little change from the 2002 inventory.

Tony

            Tony Cr. contained an expanded estimate of only 10 Coho parr in 2002 and 250 Coho parr in 2003. The 2002 juveniles were the result of upstream temperature dependant migrations from the mainstem Nestucca. The 2003 juveniles appear to be the result of a spawning event. The surveyor identified the habitat in Tony as poorly suited for Coho within the extent of the 0.5 mile survey (rapid dominated habitats with large substrates). Steelhead were present in low numbers.

Town Lake

            There were no Coho or Steelhead observed in the Town Lake tributary in 2002. Only 2 juvenile Coho were found in the first pool of the 2003 survey. The survey was initiated just above town and proceeded for 0.5 miles to an impassable log jam. The substrates were dominated by sand and silt. Some shallow gravels were present.

Trib. B

            This short 1.5 mile tributary of the mainstem Nestucca was the most productive of the unnamed tributaries. Its confluence is about one mile upstream from Fan Cr. and unlike other streams in the area it is not limited by a steep bedrock falls right at the start. The expanded estimate for summer rearing Coho reached 3,845, 1.1% of the Basin total. This represents an 8% increase from totals here last year (Trib C in 2002 database). Density levels and profiles here have remained similar to 2002 though distribution length has increased by 0.5 miles to a large impassable wood jam. A narrow canyon and a bedrock falls exist just upstream of this jam and may represent a permanent anadromous barrier. An average density of 1.4 Coho/sq.m. suggests a condition nearly seeded to capacity. High densities in the first 300 feet of 2.9 Coho/sq.m. may be augmented by upstream migrations from the mainstem. A more substantial zone of spawning followed that was centered around RM 0.5 (2.8 Coho/sq.m). This reach represents one of the best options for tributary spawning in the upper Nestucca gorge. Gradients are relatively low compared to surrounding tributaries, pools are frequent, and supplies of old wood in the channel are abundant. Steelhead were also present, several of which displayed mucous on the dorsal surface.

West

            West Cr. contained an expanded summer rearing estimate of 325 Coho parr in 2002 and 1,215 Coho parr in 2003. These juveniles were broadly distributed in low densities averaging 0.3 fish/sq.m. to a point 2.2 miles above the confluence with the mainstem. 0.3 miles above here a massive debris jam at a small tributary confluence is currently posing a definitive barrier to adult migrations. Two zones of spawning activity appear in density profiles, both averaging 0.5 fish/sq.m. The first at RM 0.9 and the second at RM 1.4. This zone marks the transition between pasture and forest habitats. The lower farmland reach contains higher reserves of fine gravels and substantial livestock exclusion fencing. Sun exposure in most pools is high and wood complexity minimal. The upper forest reach provides much more shade and wood complexity while substrates become increasingly rocky. Most juvenile Coho seen were unusually large suggesting rapid growth rates and beneficial nutrient conditions. Steelhead were also present in low densities and concentrated near the midpoint of the survey. Low numbers of juvenile Chinook were observed both years also concentrated near the survey midpoint. A distinct lack of 0+trout was observed in the lower reach until the stream entered the forest where abundance began to increase.

Wolfe

            Wolfe Cr. enters the mainstem Nestucca from the North between Foland Cr. and Tony Cr. No Coho were observed here in 2002. The 2003 inventory estimated 965 (expanded) Coho parr in low densities of 0.3 fish/sq.m. spread over 2.3 miles of mainstem and in a temperature dependent migration up 0.3 miles of the tributary Swab Cr. Two zones of Coho spawning appeared at RM 0.6 and RM 1.4 where rearing densities reached 0.6 fish/sq.m. Signs of upstream migration from the mainstem Nestucca appeared also in the first pools. Landowners near the mouth suggest that the culvert here is a passage problem although surveyor notes indicate that the crossing is passable. Habitat conditions through the survey reach appear adequate for Coho spawning and rearing. Survey notes also suggest that restoration efforts here could be very effective. 180 (expanded) 1+Steelhead were observed during the 2003 survey compared to 5 (expanded) in 2002.  No juvenile Chinook were seen this year while 115 (expanded) were observed in 2002.

Little Nestucca

Large scale increases in Coho production were also observed in the Little Nestucca. The entire Little Nestucca subbasin exhibited an expanded estimate of 62,835 summer rearing Coho Parr, an increase of 106% from 2002 totals. Coho distribution increased by 4.2 miles and was spread over 30 miles of mainstem and tributary habitat. This level of production accounted for 17.2% of the Basin wide Coho population and was equal to 40% of the mainstem Nestucca population. The mainstem Little Nestucca exhibited a radical 327% increase in its summer rearing Coho with 45% of the total population (more than doubling last year’s 22% contribution). Louie Cr. and its tributaries, which exhibited the highest production rates last year, accounted for just 12% of the subbasin total. Rearing densities in Louie Cr., and especially the Baxter Cr. tributary, remained the highest in the 5^th field. The next highest contributions were observed in Sourgrass Cr., 6.7%, and Austin Cr., 5.3%. Rearing densities in Bear Cr. and Squaw Cr. were also notable this year. Habitat in these two tributaries remains just below capacity levels, however, their short distributions has led to small 5^th field production contributions – 4.2% and 2.8%, respectively.

 (Table 5)

Expanded Little Nestucca Subbasin Wide Estimates of Juvenile Salmonid Production

Survey Year            Coho                0+              Sthd                Cut

2002                       30,555            7,580           1,735              4,260

2003                       62,835            8,870           2,185              3,440

Little Nestucca Mainstem

            The mainstem was rearing an expanded estimate of 28,150 summer Coho parr. This was more than 4 times the size of last year’s mainstem population and accounted for nearly half of the entire subbasin population. A similar production ratio was observed between the mainstem Nestucca and its entire basin. This represents a dramatic increase in production within the Little Nestucca 5^th field as well as a large shift in rearing distribution within the subbasin. The increase in the production ratio between the mainstem Little Nestucca and its tributaries reinforces the importance of mainstem habitats in basin wide Coho production. In addition, there were 3,755 0+trout (42% of subbasin total), 1,410 1+ Steelhead (65% of the subbasin total) and 1,175 older age class Cutthroat (34% of the subbasin total). 0+trout abundance in the mainstem exhibited a 44% reduction even though the basin wide trend exhibited a slight increase. 1+Steelhead numbers exhibit almost no change, and Cutthroat numbers have fallen 38%.

The mainstem Little Nestucca exhibits a complex fish distribution pattern that may be related to several interdependent variables (Geomorphology, temperature, and summer low flow regimes). Channel form seems to be the primary factor which, when combined with low summer flows, leads to the significant water quality issues (temperature) observed in the mainstem. The portion of the mainstem above the confluence of Sourgrass Cr. never exhibits any significant gradient to the 80ft vertical falls just below the confluence of Fall Cr. During the very minor summer flows, this creates a condition conducive to elevated summer temperatures, slow pool turnover rates, and potentially low levels of dissolved oxygen. In addition, because the majority of the elevation change in the active channel is observed in the bedrock falls mentioned above, the water contributed from the headwaters to the anadromous rearing reach below the falls originates from a low gradient corridor also, with the potential for exhibiting similar water quality issues. This upper reach is very nutrient rich and prolific algal blooms were observed. Coho extended to the base of this definitive barrier but their rearing densities declined as distance increased above the confluence of Sourgrass Cr.  Another clue that this upper reach of the mainstem may be water quality limited is that Stillwell Cr. continues to exhibit a Coho distribution pattern that is often indicative of an upstream temperature dependant migration from the mainstem. Tributaries with the potential for this upstream migration become high priority for proper culvert function (passage).

Average Coho rearing density in the mainstem has increased from 0.07 fish/sq.m. to 0.3 fish/sq.m. The only zone of notable density during the 2002 inventory occurred near the confluences of Louie Cr. and Sourgrass Cr. Highest Coho counts and densities occurred between RM 2 (0.7 fish/sq.m.) and RM 3.2 (0.72 fish/sq.m.). This reach is in between the confluences of Squaw Cr. and the South Fork and the cold water provided by many steep side tributaries through this zone is probably improving rearing conditions here.

Distribution profiles did not indicate that juveniles were conducting temperature dependant upstream migrations from the mainstem into Louie or Sourgrass. The very high densities observed in Louie and its primary tributary Baxter Cr. may actually be initiating density dependant downstream migrations that are contributing significantly to the seeding of the mainstem Little Nestucca. This possibility elevates concerns for the protection and enhancement of Louie Cr. and Baxter Cr.

Significantly reduced abundance of 0+ trout in the mainstem from the previous year was observed. O+ concentrations were observed primarily below RM 6. Distributions of 1+Steelhead, Cutthroat trout, and juvenile Chinook were similar and primarily below RM 3. Cutthroat trout numbers also appeared diminished between years. The total expanded estimate of Chinook was nearly insignificant at 545 and showed little change from 2002. The majority of the Chinook rearing at the date of this inventory was most likely occurring in the Little Nestucca estuary. The spread of invasive Japanese Knotweed was noted in the lower mainstem and appears to be at an early enough progression to be addressed.

Austin Cr.

            Austin was a significant producer of Coho parr during both 2002 and 2003 inventories. Distribution in 2003 increased by 0.6 miles and extended to a point 1.6 miles above the confluence with the mainstem Little Nestucca as well as 0.3 miles up West Austin. There was evidence of multiple spawning pairs. The expanded estimate of summer rearing Coho parr rose 57% to 3,690 (5.3% of the 5^th field total). The average mainstem rearing density doubled, reaching 0.9 fish/sq.meter. Peak mainstem densities were seen at RM 0.2, RM 0.6, and throughout the last 1500’ of the survey (the highest levels, averaged 1.4 fish/sq.m. and peaked at 2 fish/sq.m.). There were significant numbers of Coho observed this year in West Austin where only 2 upstream migrants were seen in 2002.  380 (expanded) summer Coho parr were found here in high densities averaging 1.7 fish/sq.m. and peaking at 3.1 fish/sq.m. This 0.3 mile reach exhibited the highest densities in Austin Cr. and contributed 12% of Austin Creeks production. Bedrock cascades in both branches limit adult escapement.

Austin did not exhibit the temperature dependant upstream migrations from the mainstem that adjacent tributaries did. This could be explained by a couple of factors, there remains a series of full spanning beaver dam complexes above sample unit 2 in the inventory. These pose definitive barriers to upstream juvenile movement. These ponds are accessible to winter adult migrants and contained some of Austin’s highest Coho counts. In addition, these beaver ponds exhibit elevated temperatures in summer and Austin Cr. at the confluence of the Little Nestucca may not have been significantly cooler (no temperature data available). Steelhead were present also in low numbers.

Bear Cr.

            1.5 miles of Coho distribution was observed in Bear Cr. at a nearly seeded average rearing density of 1.5 fish/sq.m. An expanded estimate of 2,615 summer parr accounted for 4.2% of the Little Nestucca 5^th field production total. Density levels increased steadily towards the endpoint where a peak of 2.4 fish/sq.m. was obtained. A high count in the first pool and a progression of consistently high densities suggests either an upstream temperature migration from the mainstem Little Nestucca or a rebound off of this temperature barrier by downstream density dependant migrants. Cold water supplies from Bear Cr. to the mainstem Little Nestucca are also having a positive effect on the abundance of rearing juveniles in the mainstem. Both adult and juvenile migration is limited by a bedrock falls barrier at RM 1.9.  Moderate Steelhead counts were also observed.

Bower Cr.

Bower enters the tidally influenced portion of the mainstem from the south. The start point of the survey was initiated above the actual confluence of the mainstem due to visibility restrictions and a lack of pool habitat in the entrenched agricultural segment. Coho were distributed to a point 1.1 miles above the start point in the mainstem, 0.7 miles up Trib. A, and short distances up Trib. B and Trib C. (see USGS quads). All culverts were assessed as passable for adults and juveniles except for one just above Coho distribution in Trib B where habitat appeared negligible. The expanded estimate of summer rearing Coho parr was 1,375 (2.2% of 5^th field total), up from 230 in 2002. Average rearing density has risen from 0.19 fish/sq.m in 2002 to 0.83 fish/sq.m. in 2003. Highest densities were seen in the first 0.5 miles (up to 1.8 fish/sq.m.), most likely upstream juvenile migrations from the Little Nestucca were occurring. At RM 0.9 above the start point (1.0 fish/sq.m.) there were indications of spawning activity. Distribution in Trib. A appears to be the result of temperature dependent migration. The higher reaches provide most canopy protection although flows quickly branch out into numerous tributaries. Distributions end in steep cobble and low flows.

Conklin Cr.

            This tributary was a minor contributor of Coho production with an expanded summer parr estimate of 220 (170 in 2002). The average rearing density however within their 900 ft of distribution was nearly seeded to capacity with an average of 1.4 fish/sq.m (2.2 fish/sq.m maximum). A small falls terminated juvenile distribution that appears to be passable for adults. This distribution pattern suggests significant upstream temperature dependant migrations. The tributary enters the upper Little Nestucca just below the falls and the end point of Coho distribution. Summer water quality in Conklin is far superior to that observed in the adjacent upper mainstem.

Fall Cr.

            Fall Cr. joins the mainstem Little Nestucca not far above the head of tidal influence. This stream contained multiple spawning pairs of Coho and the 2003 expanded estimate of summer rearing parr rose 55% to 1,405 (2.2% of the 5^th field total). The average rearing density rose from 0.24 fish/sq.m. in 2002 to 0.6 fish/sq.m. and the peak spawning density, occurring at RM 1, was 1.0 fish/sq.m. Rearing densities were higher in the beginning of Trib A reaching 1.8 fish/sq.m. and probably the result of upstream temperature dependant movement. Distribution in Trib A extended 0.2 miles. Distribution in the mainstem extended 1.5 miles and ended in a long stretch of boulders. All lower bedrock falls were passable. There were Steelhead present in low densities throughout the observed distribution of Coho, several of which exhibited signs of parasitic infection.

Kellow Cr.

            Kellow contained an expanded Coho estimate of 65 (40 in 2002). The average rearing density was 0.4 fish/sq.m and the peak density was 0.8 fish/sq.m. Distribution extended only 828 ft to a waterfall.

Louie Cr.

            Louie Cr. and Baxter Cr. (its primary tributary) have been classified as the most productive subbasins in the Little Nestucca 5^th field for Coho and Cutthroat. While Coho production here fell 30% in 2003, rearing densities remained higher than any other reaches. The expanded estimate of summer rearing Coho parr in 2003 was 7,610 (12% of the 5^th field total Coho production, compared to 35% in 2002). It appears that many of the Coho juveniles rearing in the mainstem Little Nestucca may have originated from density dependant downstream migrations from Louie Cr. Coho distribution in the subbasin actually increased by 0.6 miles to reach 4.1 miles total (1.4 Louie, 2.1 Baxter, 0.2 Baxter Trib A, and 0.4 Louie Trib. A). The densities in Louie Cr. averaged 1.0 fish/sq.m and the peak at RM 0.6 was 3.5 fish/sq.m. Adults passed over a difficult bedrock falls jammed with debris a few pools below the end of distribution and no further barriers were noted. Highest Coho counts in Louie occurred below the confluence of Baxter Cr. because of downstream migrants originating in Baxter.

Densities in Baxter fell slightly from the previous year to an average of 2.0 Coho/sq.m. with peak levels of 4.9 Coho/sq.m. occurring around RM 0.3. High densities averaging 2.5 Coho/sq.m. were maintained for the first 1.3 miles of Baxter where most spawning appears to have occurred. No barriers were noted at the end of distribution. This reach and the lower 0.75 miles of mainstem Louie appear to be near capacity for Coho. Louie and Baxter appear to be very important anchor habitats within the Little Nestucca 5^th field and extensive effort would be recommended for the protection and enhancement of these corridors. This pair of streams would rank as the highest priority corridors in the Little Nestucca subbasin from the perspective of current salmonid production. The abundance and distribution of Cutthroat remains high in Louie and Baxter, though abundances have fallen 55% since 2002. Expanded estimates of 385 account for 12% of the 5^th field total. This observed level of production for Cutthroat was the second highest tributary contribution and the reduction in abundance observed here follows the trend observed in the remainder of the Little Nestucca subbasin (Cutthroat numbers in the Nestucca subbasin exhibited little change).

SF Little Nestucca

            The SF extended 2.8 miles to a definitive anadromous barrier (20ft vertical bedrock falls) and included 0.9 miles of tributary distribution for Coho. Coho distribution in the mainstem terminated approximately 500 feet below the falls and Steelhead and Cutthroat were observed in low densities to the base of the falls. The expanded summer rearing Coho estimate more than doubled in 2003 to reach 10,060 (16% of the 5^th field total for both 2002 and 2003). The average Coho rearing density rose from 0.28 fish/sq.m to 0.7 fish/sq.m.  Rearing densities increased steadily from the mouth to 1.7 fish/sq.m. at RM 2.3. There were 3 tributaries that also contained Coho (Kautz – 0.4 miles, Trib A – 0.3 miles, Trib C – 0.2 miles). Average tributary rearing densities were, respectively, as follows: 0.7 fish/sq.m., 0.9 fish/sq.m., and 2.1 fish/sq.m.). Trib C1 contains a new culvert at the end of Coho distribution that was replaced based on last year’s recommendations. This culvert appears passable. It is likely that spawning has been occurring in Trib. C with Trib. C1 providing habitat mainly for upstream migrants. Expanded estimates for Cutthroat of 455 ranked as the highest among the Little Nestucca tributaries and accounted for 13% of the subbasin total.

Sourgrass Cr.

            Sourgrass had an extensive lineal distribution of Coho which extended to a point 3.3 miles above it’s confluence with the mainstem Little Nestucca. This distance represented an increase of 0.5 miles from 2002. This tributary corridor is paralleled closely by the main Highway which both confines the active channel and contributes negatively to its water quality. There was a significant accumulation of garbage and road debris in the stream corridor. Several sites have been used historically for public dumping. The Coho population here was 44% smaller than Louie Cr. with a similar mainstem confluence location. The tributary exhibits fine sandstone gravels, well scoured pools, clear flows, and ample old wood in the stream. The forest canopy here retains late successional riparian characteristics.

There is a culvert at approximately RM 0.54 with a 3 ft perch. Distribution graphics from both years suggest that this culvert has not terminated large anadromous migrants and the presence of a temperature dependent upstream juvenile migration pattern was not clear. However, this culvert is a definitive barrier to upstream juvenile migrants and a survey conducted later in the summer may result in different conclusions for the occurrence of an upstream migration. To complicate the distribution of salmonids further there is another culvert at RM 2.0 that has rusted through the bottom near the top end of the pipe. Distribution graphics from both years suggest that there continues to be a passage problem for juveniles. Some adult Coho do successfully negotiate this culvert but distinctly higher juvenile densities existing below this crossing suggest that low water passage for adults may be hindered. The pipe is under an extensive road fill and the pipe length may be as much of a factor as its condition.

            In general, Sourgrass Cr. is a significant producer of juvenile salmonids (a 6.7% contribution to subbasin Coho totals). The total expanded estimate of summer rearing Coho parr rose 15% in 2003 to reach 4,230 and the average rearing density rose from 0.68 fish/sq.m to 1.1 fish/sq.m. Peak densities of 2.4 fish/ sq.m. were observed just below the RM 2 culvert. Coho distribution continued above this culvert into excellent habitats with high wood complexities and intermittent dry channel conditions. Deeply scoured pools and cool water temperatures retained sufficient water and habitat quality for summer rearing despite the lack of flow. Significantly higher Coho production could be achieved and supported in this tributary. Low densities of Steelhead and Cutthroat were also present.

 Stillwell Cr.

            Stillwell is a significant cold water tributary in the headwaters of the Little Nestucca. Coho were distributed to a point 0.39 miles above its confluence. Coho were stopped by a wood jam just below the second culvert which appeared passable. In addition, there is some indication that the aquatic corridor is utilized by juveniles for temperature refuge from the mainstem of the Little Nestucca. The 2003 expanded estimate for juvenile Coho exhibits little change from 2002 at 380 (0.6% of the 5^th field total). The average rearing density within their truncated distribution was 1.2 fish/sq.m. No Steelhead were present this year.  

Squaw Cr.

            Squaw Cr. displays a short 0.4 mile reach of high quality spawning and rearing habitat. Deep pools were observed here between frequent outcroppings of bedrock walls and steps. A close series of steep 5 ft falls in a narrow gorge eventually terminates distribution.  Cool water and large pools shaded by steep canyon walls are present in close proximity to the lower mainstem Little Nestucca where juveniles may be seeking cold water refuge. In addition this same reach provides a short supply of spawning gravels and diverse pool types. Distribution profiles from 2002 indicated temperature dependent migrations only, while 2003 data suggests the presence of spawning activity.

Coho rearing densities here in 2003 were high, averaging 1.6 fish/sq.m. and peaking at 3.4 fish/sq.m. (RM 0.2). Average rearing density here last year was just one-quarter of this value – 0.4 fish/sq.m. Expanded estimates increased 128% to reach 1,770 summer parr. Coho production here represents 2.8% of the Little Nestuccas 5^th field total and is near full capacity. Moderate Steelhead numbers were also observed and it appears that adults of this species can pass the falls / gorge barrier at RM 0.4.

Other Surveyed Tributaries

            Judson Cr., Hiack Cr., Cedar Cr., and Mcknight Cr. all displayed limited Coho distributions in 2003 that were not present in 2002.  Populations in Judson and Hiack appeared to be the result of temperature dependent migrations from the mainstem while those in Mcknight and Cedar appear to be from a spawning event (verified by landowners in Mcknight). Average rearing densities ranged from 1.8 fish/sq.m. in Judson to 1.2 fish/sq.m. in Cedar. Distribution lengths ranged from 300 feet in Judson to 0.3 miles in Hiack. All expanded Coho estimates were under 540 summer parr. Steelhead also were seen in Cedar Cr.

Upton Cr. and Small Cr. continued to exhibit no sign of Coho spawning or rearing. A 5” drop on the highway culvert during summer flows may be restricting juvenile migrations in Small Cr. Upton Cr. appears limited by spawning gravel, pool abundance, low flows, and poor water quality. Trib A was also surveyed this year and exhibits little potential due to conditions similar to Upton Cr.   

Neskowin

(Table 6)

Expanded Neskowin (5^th field) Estimates of Juvenile Salmonid Production

Survey Year            Coho                 0+             Sthd                Cut

2002                          7,805               7,020            930               2,870

2003                        10,615               3,655         1,865               1,705

            The entire expanded minimum estimate of summer rearing Coho parr for the Neskowin basin increased by 36% in 2003. This positive trend can be contrasted with the 78% decline in the adult escapement estimate from ODFW’s SRS inventory (from 71 to 16 OCN Coho for the Sand Lake / Neskowin complex). Changes in abundance of juveniles between years in the Neskowin basin parallel the substantial increase (+92%) observed in the Nestucca Basin. While mainstem Neskowin totals have increased, the percentage of its contribution to basin wide totals has dropped from 70% to 55% indicating additional potential from tributary production.

The most productive tributaries in the Basin appear to be Hawk Cr., its tributary Butte Cr., and Sutton Cr., each flowing into tidewater and each responsible for 15%, 16%, and 5%, respectively, of basin wide production. Large increases in Coho numbers were observed in all three. Sections of Hawk Cr. and Butte Cr. represented the only habitats within the system that reached near fully seeded rearing densities. Tributaries Fall Cr., Lewis Cr., Sloan Cr., and Trib E all appear to support limited spawning, less than 3% of basin wide totals. All juvenile Coho observed in Jim Cr. appear to be the result of an upstream migration from the mainstem. The remaining tributaries showed no signs of summer rearing Coho but provide significant temperature maintenance to the mainstem. Total Coho distribution within the Basin of 10.6 miles exhibited an increase of 2.8 miles from 2002. Most of the habitat within the Neskowin basin remains under-seeded and primarily limited by adult escapement.

The Basin’s 0+trout population was reduced from 2002 by nearly 50%.  1+ Steelhead abundance experienced an equal and opposite doubling of its size. Both of these important changes occurred almost completely within the mainstem habitats and seem to be related to adult escapement patterns. Declines in 1+ Steelhead and Cutthroat should be expected for the basin in 2004 surveys. Steelhead were observed this year in all tributaries that had Coho except Sutton Cr.

Neskowin Cr. (mainstem)

 The mainstem produced 55 percent of the Neskowins summer Coho parr. The average rearing density for Coho increased to 0.3 fish/sq.m and a peak of 0.6 fish/sq.m. was observed at RM 4.5. Coho distribution continued 5.6 miles above tidal influence to a small bedrock falls, a mile short of the definitive anadromous barrier (7ft vertical bedrock falls) where distribution ended last year. Highest rearing densities during both 2002 and 2003 surveys have been concentrated between RM 3.7 and 5.1. This 1.4 mile zone begins just above the confluence of Jim Cr. and extends upstream above the mainstem bridge. This zone decreased in size by 0.5 miles in 2003 and rears approximately ½ of the mainstem rearing Coho.

A large secondary accumulation of Coho observed in low rearing densities appeared in the 2003 surveys between tidewater and RM 2.6, more than twice the size of last year’s population in this reach. This group comprised the majority of the second half of the 2003 mainstem population. Gravel beds here are among the best seen in the system and on site spawning is likely occurring. Cover and wood complexity in this reach is almost completely lacking and restoration efforts here that targeted increases in channel roughness and habitat complexity would be highly effective. Coho avoidance behavior was detected in much of the lower mainstem and indicates significant avian predation is occurring in this reach due to the open canopy and exposed pool surface areas. 

Spawning beds are spread more sporadically throughout the upper mainstem reaches between long blown out stretches of bedrock and large cobble. This reach would benefit greatly from large in-stream log placements that could trap gravel. Spawning potential in the lower reach and carrying capacity for the mainstem in general could support much higher Coho production rates than are currently being realized. The mainstem appears to be primarily limited by low adult escapement.

Steelhead numbers in the mainstem rose by 105% in 2003. The highest concentrations were observed upstream between RM 4.3 and the survey endpoint at RM 5.7 where the majority of the 2002 0+trout population was observed. 2003 0+ trout numbers fell by 51% in the mainstem. Most of this reduction appears to have occurred in the final reach of the survey where peaks were observed in 2002. Counts were evenly spread throughout the mainstem in 2003 with no noticeable zone of concentration. 82% of the 1+Steelhead observed within the 2003 Neskowin basin survey were found in the mainstem. Additional Steelhead rearing was occurring upstream of the inventory end point.

Hawk Cr.

            Hawk is a tributary of Neskowin Cr. that enters the mainstem west of Hwy 101. Both Hawk and its major tributary Butte Cr. contained Coho and combined produced 31.6% of the summer standing crop of Coho in the basin (16% in 2002). Improvement was greatest in Butte Cr. where expanded estimates rose 271% to reach 1,725 Coho summer parr and distribution increased by 1.5 miles. This reach contained the highest rearing densities in the basin and represented the most productive tributary habitat. Expanded Coho estimates in Hawk Cr. rose by 102% to reach 1,630 summer parr and distribution increased by 0.9 miles. In addition, Steelhead were present in both Hawk Cr. (140 expanded) and Butte Cr. (40 expanded).

Hawk Cr. runs through the Hawk Creek Golf Course, crosses under Hwy 101, then winds through a wetland and residential area before entering the Neskowin estuary.  While traversing the golf course, a large portion of its lineal distance lacks any riparian vegetation.  The primary water diversion at the Neskowin Water Plant is the water source for the community of Neskowin. The lower stream channel was dominated by shallow riffles and channel manipulation has eliminated most sinuosity. The largest and deepest pools were found in this lower mile, however, along with the majority of the Hawk Cr. Coho population. The best of these pools exist between the tidewater slough and the Highway 101 culvert where willow and alder almost cover the stream and beaver activity was noted. The stream contained Coho for 1.8 miles well above the golf course impacts and into the upper forest habitats. Pools become less frequent in the upper reaches as flows diverge into small tributaries and long stretches of cobble and riffle dominate. Coho juveniles were noticeably smaller above the golf course indicating a significant difference between the two habitats in nutrient levels, food abundance and growth rates. The average rearing density for Coho increased from 0.27 fish/sq.m in 2002 to 0.9 fish/sq.m. in 2003 with two peaks of 1.4 fish/sq.m. at RM 0.3 and RM 1.4.

Butte Cr. contained Coho for just 0.64 miles in 2002 at an average rearing density of 0.42 fish/sq.m. A dramatic increase in escapement seems to have occurred during the winter of 2002 which increased Coho distribution to 2.1 miles above the junction with Hawk Cr. at the tide gate. The additional 1.4 miles of distribution extended into the finest portion of habitat in the stream and ended with no barriers in a zone of high potential for production. Coho rearing densities increased to an average of 1.0 fish/sq.m. with peaks of 2.6 fish/sq.m. at RM 0.7, 1.7 fish/sq.m. at RM 1.2, and 2.4 fish/sq.m. at RM 1.7. A long zone of shallow and exposed glide/riffle habitat extends from the tidegate through the golf course to the first pools below the Highway 101 culvert. The highest counts for Coho were observed in the following 0.5 miles in large pools with high grassy banks and fine gravels. Good gravels and deep scour continue into the forest where wood complexities begin to increase. This culvert was approximately 100 ft. long and has sagged significantly near its center. The low spot has filled with sediment to ½ its potential volume.

Distribution continues through numerous passable culverts and the channel gradient increases exposing larger cobble and rock.  Pools become smaller and less frequent though water quality improves (lower temperatures). Canopy coverage through this reach is excellent and abundant wood contributions were noted. Distribution terminates where stream gradients decrease again in a zone of high sinuosity and fine gravels. Carrying capacity for Butte Cr. appears significantly higher than current levels due to the habitats still available at the top end of their current distribution.

Jim Cr.

            Jim Cr. was a significant contributor of flow to the mainstem during summer flow regimes. There were Coho present which appeared to be the result of a temperature dependent migration from the mainstem with an expanded estimate of 95, less than 1% of the Neskowin Basin total. Distribution extended just 421 feet. Indications from habitat observations are that substantially higher populations could be supported here. Steelhead were observed.

Lewis Cr.

            Lewis Cr. is another major contributor of summer flow. The abundance of Coho here continues to be significant with an expanded estimate of 275 juveniles in 2003 and 375 in 2002. There was a spawning peak identified at approximately 2,500 ft. during both surveys. This level of production represents approximately 2.6% of the Neskowin basin total. The average rearing density for Coho shows little change at 0.5 fish/sq.m.  Coho distribution ended at a 5 foot falls over a large sill log. Spawning habitat above RM 0.6 appears limited by the abundance of bedrock and large boulders. Habitat below this point appears well suited for Coho spawning and represents one of the best tributary options along with Hawk Cr., Fall Cr., and Trib E. Steelhead were also present in the subbasin and juvenile salmonid production continues to be limited primarily by a lack of adult escapement.

Fall Cr.

            Fall Cr. enters from the south through a 380 ft long culvert under Hwy 101. The culvert appears to be passable with limited Coho spawning and rearing occurring above. 2003 surveys saw expanded Coho estimates drop from 140 to 55 and distribution fall from 0.8 miles to 0.4 miles. This represents one of two tributaries exhibiting reductions in Coho production in the basin during 2003 surveys. There were low numbers of Steelhead present also. There is a 4ft drop into a plunge pool below the culvert that is complicated by a large sill log and represents a definitive barrier for the upstream migration of juveniles. The limited abundance of juvenile Coho above the culvert and in Trib A, therefore, are the result of adult spawning. The significant decline in abundance and distribution above the culvert in 2003 may suggest that adults are also being discouraged by the conditions below this culvert. Excellent habitat exists in Fall Cr. with at least 1 mile of deep pool scours, abundant gravels, and high flows. Water quality (temperature) in this tributary is excellent and the result of an intact late successional canopy and the current land use in the headwaters on Cascade Head. Maintenance or alteration of the downstream culvert condition is of the highest importance to the continued use of this stream habitat.

Prospect Cr.

            Prospect contributes significant summer flow to the mainstem Neskowin. The aquatic corridor exhibited steeper gradients and larger substrates than adjacent tributaries (Jim, Lewis). There were low densities of Coho observed in 2002 with the expanded estimate totaling 40 juveniles. No Coho were seen here in 2003. No Steelhead were observed here in 2002 while low numbers were observed in 2003.

Sloan Cr.

            Sloan was a minor contributor of summer flow to the mainstem with salmonid production limited by habitat size and passage issues. The best aquatic habitat existed in the lower end, which exhibited larger pool surface areas. Coho were present with an expanded estimate of 110 for 2002 and 200 for 2003 (1.9% of 2003 total). The average rearing density for Coho increased to 0.7 fish/sq.m and a peak of 1.4 fish/sq.m. was observed at RM 0.2. Data from both 2002 and 2003 suggests that spawning has taken place here. Coho distribution extended for 0.5 miles up to an impassable double culvert. Two 4 foot diameter pipes which have rusted through allowing flows to drain out through the middle of the culvert and to erode substantial amounts of fill from underneath the road crossing. In addition, the drop from the mouth of the culvert to the pool below was large and impassable for both adults and juveniles even if flows were making it out the end. This crossing is a high priority for both passage and road maintenance. Abundant supplies of good gravel and fallen timber exist within the stream channel upstream of this culvert. The only Steelhead observed in Sloan Cr. were present in the plunge pool below this culvert. 

Trib E

            This Tributary is a minor contributor of summer flow coming into the mainstem just below the group camping area at the upper mainstem bridge. This tributary was noted as Trib F in the 2002 database. The main road culvert for Trib E exhibits a substantial drop that remains passable for adults but may present an obstacle under low flow conditions. Juvenile passage is denied at the culvert though no temperature dependant upstream migration was detected. Coho distribution increased from 0.2 miles in 2002 to 0.7 miles and no additional barriers to escapement were observed. The average rearing density decreased from 1.85 Coho/sq.m. in 2002 to 1.2 Coho/sq.m.  Expanded estimates more than doubled from 105 to 275 (extended distribution). The high peak from 2002 of 2.69 Coho/sq.m. fell to 1.8 Coho/sq.m. and was found at the end of the survey. More gravel exists in this tributary than in most surrounding tributaries and distribution length was greater here than in any of the upper basin streams. Coho in Trib E were not seeded to capacity within this distribution in 2003. Steelhead were found in 2003 here while none were observed in 2002. Basin-wide adult escapement is the primary limiting factor to full seeding in this tributary.

Sutton Cr.

            Noted as Trib A in last year’s database, this tributary meets the mainstem just above the beach and climbs to the south through a private housing community. Numerous culverts exist throughout 0.64 miles of Coho distribution. No Coho were observed here last year. Tidally influenced conditions limited the effectiveness of the survey methodology for the first 0.3 miles through long shallow trench pools covered with heavy silt and poor visibility. Above the first main road culvert at RM 0.3 a heavy metal trash rack was installed to prevent beavers from damming up the culvert.  Upstream of the culvert, beaver dams have created an extensive marsh with numerous channels and backwaters.  At the time of survey this culvert appeared impassable to both juvenile and adult migrations mainly due to the height and density of debris accumulated against the trash rack.  The grate itself appears passable with 5” x  8” rectangular openings. Visibility was slightly improved in some sections of this marsh, which extended through the next main road culvert, and high densities of Coho juveniles and Cutthroat trout were observed here. An accurate Coho count and surface area calculation was compromised by spotty visibility and the irregular shape of the marsh (the irregular shape is due to the network of private roads surrounding the marsh.)  Somewhere between 300 and 800 (expanded) Coho juveniles were rearing here with at least 36 older age class Cutthroat trout. This represents about 5% of basin wide Coho totals and stands out as the third most productive tributary to the Neskowin for 2003. A dense layer of silt covered the bottom of this marsh habitat.

Stream conditions upstream of the marsh improved quickly and abundant supplies of clean gravel were present. Flows remained very low for the rest of the survey, however, and pools were small. Very low numbers of juveniles were found rearing in this upper half of Sutton Cr. It is likely that most spawning is occurring in these upper zones of gravel during winter flow conditions and when flows subside the poor rearing conditions (lack of pool surface area) force most of the juveniles to migrate down into the extensive side channels and flooded grasses below. Poor dissolved oxygen conditions and high water temperatures appear to be the main limiting factor to summer rearing in this marsh. A badly rusted culvert with a 3” drop at RM 0.6 has much of the stream flow draining through holes in the middle of the pipe and represents a problem for upstream juvenile migrations. No Steelhead were observed in Sutton Cr. Maintenance of the debris accumulation on the trash rack at Rm 0.3 could be annually critical for maintaining utilization by anadromous salmonids.

Sand Lake

2003 Surveys conducted in the Sand Lake basin assessed the condition of 8 miles of available habitat. Summer rearing Coho parr were observed in 5.5 of these miles. Coho distribution here exhibits a change of just 0.1 miles between years. Expanded Coho estimates, however, decreased 29% in the Basin in 2003 despite large increases in production observed in the Nestucca and Neskowin basins.  The greatest decreases were observed in Jewell Cr. and Andy Cr.  Several pools in the system could not be snorkeled due to poor visibility from tannins and / or sediment. The worst sections for visibility existed in Trib A of Sand Cr., lower Sand Cr., Trib A and Trib B of Sand Lake, and Davis Cr. These habitats appear to be of negligible importance to anadromous spawning due to the absence of spawning gravels. They can however be important sites for rearing dependant on annual seeding levels. Refer to the USGS quads included as a product of this inventory to identify the start points and the location of unnamed tributaries.

The Sand Lake Estuary contains a single primary source of potential salmonid habitat, Sand Cr. This creek is a 4^th order stream with three significant tributaries, Jewell, Andy, and Davis. Sand Cr. and tributaries accounted for 87% of the basin’s summer rearing Coho in 2003 compared to 100% in 2002. 60% of the basin total was rearing in mainstem Sand Cr. 100% of the basin’s Steelhead were observed in Sand Cr., 70% of them in Jewell Cr. In addition, the estuary receives extremely high quality fresh water input from three 2^nd order streams that enter on the southern end of the bay, Gurtis, Reneke and Beltz.  Small Coho abundances were observed this year in Beltz and Gurtis.

(Table 7)

Expanded Sand Lake (5^th field) Estimates of Juvenile Salmonid Production

Survey Year            Coho                 0+             Sthd                Cut

2002                        2,940              2,345           155                1,335

2003                        2,085              1,215           195                   725

Sand Cr.

            Coho and Steelhead were observed within the mainstem of Sand Cr. during both 2002 and 2003 surveys. The expanded abundance of summer rearing Coho for all of Sand Cr. and its tributaries fell 38% from 2,940 in 2002 to 1,820 in 2003. Additional production is likely present in 16 % of the lineal habitat uninventoried below Galloway Rd. due to poor visibility. The presence of juvenile Coho here during 2002 surveys was significant since ODFW’s  SRS adult estimate for the year 2000 was 0. Coho distribution increased 0.6 miles in mainstem Sand Cr. and reached 3.9 miles above the head of tidal influence. The primary spawning activity was observed between RM 2.5 and RM 3. The stream rises out of dark slack waters above Trib A and enters a zone of well scoured gravels and higher flows. This reach represents the finest spawning opportunities available in the basin.

The average rearing density for Coho was 0.2 fish/sq.m of pool surface area with an observed peak density of  0.75 fish/sq.m. A smaller spawning peak of 0.6 fish/sq.m. was present at RM 1.7. Coho distribution ended in 2003 above several small tributaries in small pools and a narrow channel alongside heavy clearcuts and piles of slash.  Steelhead were present in the system but much less abundant than Coho and concentrated in a much narrower band of habitat from RM 1.6-2.7. The potential for restoration is significant in mainstem Sand with visible impacts from upslope harvest activity and agricultural use present.

Jewell Cr.

            Jewell exhibited an average Coho rearing density similar to last year at 0.24 fish/sq.m. with a peak density of 0.4 fish/sq.m. at RM 0.4 (peak density here last year reached 1.4 fish/sq.m.). Distribution extended 0.9 miles, losing 0.5 miles from 2002.  Expanded estimates of Coho abundance here fell 55% to 355 (20% of Sand Cr. totals). Temperature dependent migrations of Coho summer parr were evident in the lower pools as well as spawning activity at RM 0.4. There were moderate numbers of Steelhead present (135 expanded) and Cutthroat (115 expanded). More Steelhead were found in this reach than anywhere else in the basin.

Andy Cr.

            Andy Cr. contained abundant gravels that were well sorted. The average density of Coho declined from 0.37 fish/sq.m in 2003 to 0.24 fish/sq.m. in 2003.  Peak densities declined from 1.1 fish/sq.m. to 0.5 fish/sq.m.  A zone of spawning activity was observed at RM 0.5. Coho were sparsely distributed and extended 0.6 miles above the confluence with Sand Cr., a loss of 0.6 miles from 2002. Andy Cr. sustained the largest Coho decline in the basin in 2003 (- 83%) and expanded estimates dropped to 195 summer parr. This represents a decrease in basin contribution from 39% in 2002 to 9% in 2003. The production potential is significantly higher in this tributary and the observed reduction probably the result of limited adult escapement. Habitats in Jewell Cr. represent the best tributary spawning gravels in the basin. Distribution ends in riparian clearcuts with high levels of solar exposure. There were no Steelhead observed.

Davis Cr.

            Davis was classified as exhibiting low gradient swampy habitat with very little if any potential for spawning. The substrates were silt dominated. There were only Cutthroat observed, no Coho or Steelhead present. Abundant beaver activity was noted.

Trib A.

            This tributary of Sand Cr. was completely mud / silt dominated with limited to no potential for spawning. No fish were observed.

Sand Lake Southern Tributaries

            Three 2^nd order tributaries entering from the southern side of the estuary (Gurtis, Reneke, Beltz,) exhibited significant summer flows that were contributing very cold water to the shallow Sand Lake estuary. All three of these tributaries originate on a north slope and emanate from well canopied headwaters. Two of the streams currently exhibit passage problems at the main hwy culvert.

The 3 ft culvert on Beltz has a 3.5 ft drop to the stream channel and may pass adults but is a definitive barrier to the potential upstream temperature dependant migrations of juveniles. Very low numbers of Coho juveniles (5 expanded) were observed here in 2003 probably seeking cold water refuge. The 1 ft culvert on Reneke is almost entirely blocked and is probably not passable for adults or juveniles. It is 2 ft. wide and 35 ft. long. No Coho or Steelhead were observed here either year.

The crossing on Gurtis is in good condition. 260 (expanded) juvenile Coho were quantified here this year for the first time below the culvert in trench and beaver pools. A steep boulder falls just above the culvert probably discourages utilization of the upper basin by anadromous species. Coho here also appear to be seeking cold water refuge. No Steelhead were observed. Multiple domestic water diversions were present within the Gurtis Cr. survey.

None of these tributaries are high priority for large anadromous spawners because of the limiting size of the habitat. There is however, the potential for these three streams to be very significant players in the health and productivity of the intertidal wetlands and estuary that they contribute to. In addition, juvenile salmonids appear to be utilizing these cold water habitats for thermal refugia.

Tribs A and B of Sand Lake show little to no potential for adult or juvenile usage. Trib A contained a 1ft by 35ft pipe culvert beneath the highway and no scour pool habitat. Trib B had an impassable dam and a 1.5 ft by 90 ft pipe culvert that accesses pasture trench habitat.

            There are several conclusions based on the preceding analysis that lead us to the point of developing some general recommendations.

·        The weir at the Cedar Cr. facility, in the Three Rivers subbasin, may be problematic for some wild salmonids. Retrofitting the weir at the Cedar Cr. site with a sorting facility and a Three Rivers water supply to the fish ladder could result in a significantly higher level of wild production for at least OCN Coho than is currently achieved. Additional benefits could also be realized by wild Winter Steelhead, wild Fall Chinook and Sea run Cutthroat Trout. Phase 2 plans previously submitted to the R&E Board already outline the changes and designs necessary for the trapping and sorting at this site that would provide the discrimination required to pass or retain adults without truncating run timing and effectively denying access for certain components of each population. Re-visit the phase 2 option, clearly state the objectives and benefits to wild salmonids and review any alternate strategies that may be more cost effective solutions than previously proposed.

·        The mainstem Nestucca continues to be very high priority for restoration and enhancement because of the observed production potential for all salmonids. This suggests that the maintenance, enhancement and preservation of water quality in the mainstem are paramount. This also suggests that a well developed monitoring strategy is essential for quantifying the inter / intra annual trends in water quality parameters. Prioritize restoration reaches by species and continue to develop an understanding of the winter habitat requirements of salmonid juveniles rearing in the mainstem.

Distribution and Rearing Density Graphics

            For both the year 2002 and 2003 survey effort, an Excel Pivot Table has been developed that allows the user to preview distribution, density and abundance graphics by stream. This database allows managers and users to access trend information for all of the basins and subbasins in the Nestucca / Neskowin management area including direct ocean tributaries. Please contact the Nestucca / Neskowin Watersheds Council for an updated version of this tool.