The proponents provided much more detailed data to address the ISRP’s questions, and these data were very useful. In particular proponents have responded favorably to our suggestion to develop methods to include adult steelhead abundance estimates in Abernathy and extrapolated to Germany and Mill Creek for an evaluation of supplementation.

One question that was not addressed, and perhaps we failed to emphasize it, was the actual number of individuals that were assigned to single or parent pairs in the parentage analysis, and how many individuals that were genotyped were not assigned to a parent. The numbers (and proportion) of fish not assigned needs to be presented and adequately discussed in any future proposal for completion of this project.

The challenge with this project is not executing the lab work but the logistics of the field work, namely, to meet the sample sizes required to have sufficient data. From the ISRP perspective, the question posed circa 2000, about establishing a broodstock using wild parr and producing smolts and subsequent anadromous adults from them has been answered. The questions for which support is currently being provided are the relative reproductive success of hatchery versus natural origin steelhead and the demographic consequences of supplementation. Since Germany, Mill, and Abernathy Creeks are intended to serve as reference and treatment locations respectively, the near genetic equilibrium among them, with the conclusion they have large amounts of gene flow, complicates any analysis. The challenge is twofold: First, for a demographic analysis you need a reasonable estimate of the adult progeny produced from natural spawning. If the three streams are functionally panmictic, adults attributed to one stream based on redd counts may have originated in one of the other streams. Second, if the implied large proportion of unassigned adults or juveniles is owing to adults that avoided capture at the electric weir, effort is being expended on genotyping individuals for which no useful conclusion can be reached.

Unless all of these logistical challenges can be resolved in future proposals, this project should be designed to complete the RRS and supplementation evaluation tasks over the next few years, and then be concluded. The project should be included in the Columbia River Hatchery Effects Evaluation project as part of consideration of basinwide evaluation. If the data are not suitable for meaningful evaluation the project should be brought to a reasonable conclusion.

If the logistic challenges can be resolved this study will provide an important replicate of the relative reproductive success of hatchery steelhead developed from a local broodstock, adding to the range of locations to help meet BiOp needs.

The ISRP requests a response that provides two primary items. 1. The response should provide a succinct, yet complete, presentation of the accomplishments of all facets of the project. This includes: • the number of parr collected each year to establish broodstocks the smolts released from these initial broodstocks • the estimates of smolts leaving the system from these releases and those residualized in the stream • natural smolt yield before beginning supplementation • adult returns to the stream from natural and hatchery production (by release year) • estimates of steelhead spawning below the hatchery weir site • numbers of hatchery and natural steelhead passed above the weir for natural spawning • estimates of juvenile (parr or smolt) production from natural spawning by natural and hatchery-origin adults, and • estimates of RRS of hatchery and natural-origin adults. The presentation should include the primary data (actual counts of fish), analysis of the primary data, interpretation of the analysis, and use of this interpretation to justify the approach to completing the study design in the 2003 proposal. The submitted proposal and presentation to the ISRP often provide conclusions without transparent supporting data. Portions of the proposal and presentation are contradictory. And within the proposal, conclusions in various places are often contradictory or cannot be easily associated with specific data. As an example, in the proposal in the accomplishments section there is a statement: steelhead smolt production has declined in the last few years in Abernathy Creek, whereas Germany and Mill Creeks (control streams) have been more variable (figure 1). These results suggest that this supplementation strategy may have negative consequences from either HOR smolt release or HOR adults spawning in the wild. Slide 9 in the presentation has bullet points stating that smolt production is equivalent between pre- and post-hatchery production years and that HOR emigration rates, timing, and patterns are similar to NOR fish. The text accompanying the presentation states: “These results suggest that smolt production within Abernathy Creek has not been negatively effected by hatchery production thus far.” A second example: the proposal accomplishments section states that, “Improper synchrony of HOR physiological processes associated with smolt transformation may increase the percent of HOR fish that elect to remain in fresh water or reduce survival. The consistent differences we have observed in HOR and NOR steelhead physiology and morphology may be positively related to the proportion of HOR fish that remain in Abernathy Creek (residualize) annually.” But in the next paragraph: “we evaluated spatial and seasonal overlap in habitat use and behavior between yearling HOR steelhead released from the AFTC and NOR salmonids. During spring, the majority of HOR smolts migrated downstream and left the system soon after each of three releases, whereas NOR smolt migration was more protracted following a normal distribution with one central peak. This suggests that the highest potential for ecological interaction between NOR and HOR at the smolt life states occurs downstream of the release location and within the first few days after each release.” Later in the same paragraph: “Our results suggest that there is a potential for hatchery fish to affect wild steelhead populations due to dietary overlap and salmonid fry predation.” In the adaptive management section the proposal states: “Our results suggest that a small portion (1% - 7%) of HOR released smolts did not emigrate.” For most of the essential production, demographic, and genetic objectives there is similar inconsistency within the proposal. 2. The response should also address the qualifications identified by the ISRP in the 2007 review. The 2007 ISRP review summary stated: “The sponsors made a diligent effort to rapidly respond to the ISRP’s questions. For the most part, however, their answers are only partially satisfactory. One major difficulty with this project lies with the comparison of adult abundance estimates in the reference streams (Germany and Mill Creeks) and the treatment stream (Abernathy Creek). The sponsor’s are apparently unable to verify (with presently collected data) assumptions involved with redd counts, which will be used to assess adult abundance in the reference streams. The response lacks a description of how the error associated with the abundance estimates will be assessed, and there is difficulty in accurately assessing other demographic characteristics such as sex ratio, age structure, and redds per female. The sponsors fail to plainly explain how they will account for confounding effects, such as habitat restoration actions, planned sometime in the future for Germany and Mill Creeks.” The recently submitted proposal continues to emphasize the opportunity to contrast production, demography, and genetic evaluations in reference and treatment streams. The proposal executive summary states: “We have started to compare the reproductive success and demographic changes (to both juvenile steelhead production and adult returns) occurring within Abernathy Creek to two control streams (i.e. Germany and Mill creeks) to determine whether supplementation was successful...” However, the accomplishment section provides no data on adults in Germany and Mill creeks. None of the objectives identify a demographic comparison of adults in reference streams to a treatment stream, and there are no objectives to obtain data on adult steelhead in Germany and Mill creeks. The ISRP raised concerns in the 2007 review about the sufficiency of data to assess and interpret relative reproductive success (for a variety of reasons), and demographic consequences of supplementation (for a variety of reasons) (see 2007 review). These concerns need to be resolved during this response loop.

  

 

 

Dr. Kenneth Ostrand, Technical Contact                                           November 8, 2010

Abernathy Fish Technology Center

U.S. Fish and Wildlife Service

1440 Abernathy Creek Road

Longview, Washington 98632

  

Dear Independent Scientific Review Panel,

 

Enclosed are our responses to each of the Independent Scientific Review Panel (ISRP) comments for the proposal titled Natural Reproductive Success and Demographic Effects of Hatchery-Origin Steelhead in Abernathy Creek, Washington; BPA Project No. 2003-063-00; Contract Number No. 45565).   

We appreciate the time and thoroughness of the ISRP reviewers.  We believe that we have addressed all of the reviewers’ comments.  As a result of the ISRP comments an objective has been added to the 2012 proposal scope of work that focuses solely upon acquiring, analyzing, and interpreting adult return data within the treatment and control creeks.

Please contact me if you require any additional information.  Thank you for your time and consideration.

 

Sincerely,

Kenneth Ostrand

Regional Ecologist

 

XC: Denise Hawkins, Patricia Crandell

 

Response to ISRP:

 

Primary Item 1:

 

• Our results demonstrate that a “native” or “endemic” hatchery broodstock of steelhead useful for supplementation can be obtained by capturing age 0+ natural origin (NOR) juvenile steelhead and rearing them to sexual maturity.  NOR juveniles collected in Abernathy Creek and reared at Abernathy Fish Technology Center (AFTC) accepted commercial salmonid rations and survival to sexual maturity at age-3 was high (Range = 79 to 97%) for the three collection years (1999, 2000, and 2001; Table 1).  Once NOR steelhead reached sexual maturity, they were used as broodstock to produce hatchery origin (HOR) progeny that were released within Abernathy Creek.  For example, NOR juveniles collected in 1999 reached sexual maturity in 2002 and produced 29,724 HOR F₁ progeny that were released in 2003.  Based on a predominately age 2-salt life history, the majority of adult HOR F₁ steelhead returned in 2005 and were subsequently included in that year’s broodstock. Subsequent NOR juvenile steelhead collection years (i.e. 2000, 2001) followed a similar rearing, release, and return pattern.

  

Table 1.  NOR steelhead juveniles were collected annually (1999, 2000, and 2001), reared to sexual maturity, and subsequently used as broodstock.  The broodstock produced HOR smolts (range = 29,724 to 19,049 smolts) that were released from Abernathy Fish Technology Center.

  

• We estimated the number of HOR steelhead smolts released from AFTC leaving the system and residualizing within Abernathy Creek to determine their potential reproductive contributions to the population (Table 2).  Of the HOR steelhead smolts released annually (mean = 22,118, SE = 1,602) from AFTC, only 61% (mean = 13,600, SE = 1,200) survived and left Abernathy Creek.  Additionally, 0 to 7% of HOR fish residualized and became residents (mean = 542, SE = 144); however, relatively few resident steelhead contributed reproductively to the population compared to those with an andromous life history (Table 7).  The number of offspring produced per resident HOR fish (mean = 0.06) appeared to be far less than that of resident NOR fish (mean = 0.6; Table 7).  Preliminary evidence, via otolith microchemistry, suggested that the supplementation program at AFTC had not increased the number of resident fish reproductively contributing to the population.  Of the offspring (N = 87) collected within Abernathy Creek, only 11% had a resident mother, a result not statistically different (P > 0.05) from the two control streams (Germany Creek = 0% and Mill Creek = 34%).  These results collectively suggested that the majority of juvenile steelhead had anadromous parents versus resident parents.  Additionally, our results suggested that anadromous parents contributed far more offspring than did resident fish.  However, the AFTC steelhead supplementation program will need to be monitored in succeeding generations, particularly if these life history forms are heritable;; the goals of conservation hatcheries will not be met by increasing the proportion of resident fish produced.  Sampling of the progeny in succeeding generations and further genetic analyses will help to clarify this potential pitfall.

 

Table 2.  The estimated number of smolts released from Abernathy Fish Technology Center, HOR smolts that emigrated out of and those that became residents within Abernathy Creek.

  

• AFTC began to release adult HOR steelhead to spawn naturally above the electrical barrier weir in 2005; thus the effect of hatchery supplementation on natural smolt production first occurred in 2007.  As a result 2002, 2003, 2004, 2005, and 2006 were considered pre-hatchery supplementation years and subsequent years were considered post-hatchery supplementation years (Table 3).  Although within year estimates of variance are still being calculated for most years by the Washington Department of Fish and Wildlife (WDFW), preliminary estimates suggested that steelhead smolt yield had not been negatively affected by the hatchery supplementation program at AFTC or the removal of juveniles to create the broodstock.  Our preliminary results suggested that smolt production declined within all the creeks (F₅, ₁₈ = 8.7, P < 0.05), and there was no significant increase or decrease in smolt yield due to supplementation (Stream × Treatment Interaction: F₅, ₁₈ = 1.43, P = 0.26) as compared to control streams.  Once within year variance estimates are available, a more rigorous computation (e.g.  paired BACI design) comparing smolt production pre-and post hatchery supplementation among creeks can be completed.  Continuing to estimate smolt yield will allow the estimates to be more scientifically defensible since three years of post-supplementation data may not fully reflect annual variability within smolt yield and abiotic conditions.  Acquiring more data will provide a broader scope of inference for determing the effects of hatchery supplementation and insights for use throughout the Columbia River Basin.

 

Table 3. Estimates of natural-origin (NOR) steelhead smolt yield within Abernathy, Germany, and Mill creeks.  Smolt yield was obtained using rotary screw traps operated by Washington Department of Fish and Wildlife.

  

• One of our main objectives was to obtain a sufficient number of NOR and HOR adult steelhead for our broodstock so we could spawn adults randomly and equalize parental genetic contributions.  The number of adult NOR steelhead returning to AFTC was relatively low from 2005 to 2009 but doubled in 2010.  In contrast, the number of HOR adult steelhead returning to AFTC more than tripled since 2007 and remained relatively high through 2010.  We propose to continue trapping adult steelhead at AFTC, and adhere to spawning protocols in hopes of minimizing genetic divergence between HOR and NOR populations.  Moreover, due to the complex nature of population abundance patterns in relation to local and marine environmental conditions, additional years of data in conjunction with redd surveys in Abernathy, Mill, and Germany creeks are needed to assess the demographic change of Abernathy Creek steelhead due to supplementation practices.  Although increasing trends in adult return rates in Abernathy Creek are promising, they have only been observed during the last few years.  Continuing to determine the adult return rates should make the estimates more scientifically defensible given that adult salmonid return rates can fluctuate widely from year to year.  Accounting for this inherent variability is imperative, particularly if management decisions will be based upon conclusions of this study. 

   

Table 4.  Adult natural origin (NOR) and hatchery origin (HOR) steelhead returns to AFTC.  Electric barrier weir operation began in the fall of 2005 and has been operated each subsequent year from October through (at least) May.

Year	NOR	HOR	Stray-HOR
2005	34	38	36
2006	32	49	62
2007	26	58	50
2008	24	189	60
2009	40	148	67
2010	80	229	64

 

• Estimates of the number of steelhead spawning in all of Abernathy Creek and in the creek below AFTC’s electric barrier weir, based on redd counts, have been estimated by WDFW (Table 5).  Although the validation of redd counts as an appropriate surrogate for the number of  adult steelhead has been beyond the scope of our study to date, we have included a new objective (OBJ 9) within the proposal to extend the duration of operation of an adult picket weir at the mouth of Abernathy Creek.  The weir would be operated throughout the adult steelhead return season.  We propose that by using redd counts collected on Abernathy, Germany, and Mill creeks and by operating the adult picket weir on Abernathy Creek throughout the adult steelhead return season, we will be able to validate current redd counts and more accurately assess demographic characteristics such as sex ratios, age structure, and redds per female.  The addition of this objective to the proposal will provide additional information about adults in the treatment stream (Abernathy Creek) and the two control streams (Germany and Mill creeks).

 

Table 5.  Adult steelhead escapement estimates for Abernathy Creek.  Escapement counts include estimates from Cameron Creek (a tributary to Abernathy Creek).  Escapement estimates were determined via redd counts (Bryce Glaser, WDFW). 

Year	Total Steelhead escapement	Downstream of electric barrier weir
2005	116	84
2006	154	130
2007	200	82
2008	248	90
2009	302	86

• To assess the relative reproductive success of HOR and NOR steelhead spawning in the natural environment, AFTC releases NOR and HOR adult steelhead into Abernathy Creek above the electric barrier weir to spawn naturally. The first year of upstream releases began in 2005 after the weir was built at AFTC to control upstream migration of steelhead.  Additionally, 2005 was the first year of expected HOR adult returns from the first (2003) HOR smolt release.  HOR and NOR natural spawners passed upstream in 2005 produced progeny that emigrated to the ocean in 2007 and returned in 2009.  Thus, 2009 was the first year where returning adults consisted of those produced naturally in the stream by HOR and NOR adults spawning sympatrically.  Over the next several years, we will have a number of adult fish returning that were produced by HOR and NOR spawners naturally in the creek.  As mentioned previously, due to the complex nature of local and marine environmental conditions, it will be necessary to continue this project for the next several years in order to provide a robust assessment of relative reproductive success of HOR and NOR steelhead spawning in the natural environment across a broad spectrum of environmental conditions. 

 

Table 6.  Number of adult natural origin (NOR) and hatchery origin (HOR) steelhead passed above the electric barrier weir for natural spawning.

	NOR		HOR
Year	Male	Female	Male	Female
2005	2	4	4	1
2006	17	8	9	5
2007	11	7	9	5
2008	10	12	20	34
2009	18	20	8	9
2010	26	27	12	12
Total	84	78	62	66

The supplementation program at AFTC will follow these protocols for retaining broodstock and for passing adult steelhead:  1) retain 1/3 of all captured adult NOR steelhead for broodstock; retain twice as many HOR as NOR steelhead for a total of no more than 200 spawners, 2) spawn fish  using a factorial mating design (2 males x 2 females), 3) release the other 2/3 of all captured NOR adult steelhead above the weir  to spawn naturally and release HOR steelhead above the weir  such that 1/3 to 1/2 of the adult steelhead passed upstream are HOR.  The number of males and females passed upstream, of each origin (NOR or HOR), should be equivalent (equal numbers of HOR males and HOR females, equal numbers of NOR males and NOR females).

  

• Our data show that the reproductive success of HOR adult steelhead spawning naturally in Abernathy Creek was lower than that of NOR adults for both anadromous and resident parents (Table 7).  Two exceptions to this trend occurred when the reproductive success of HOR parents was nearly equal to that of NOR parents in a single group (resident parents in 2007 and anadromous parents in 2009).  Despite this, the overall reproductive success of HOR fish (anadromous and resident) in those years was 40% (2007) and 50% (2009) that of NOR fish.  The number of offspring produced per individual was highly variable for both NOR and HOR adults but anadromous parents of both types generally produced more offspring than did their resident counterparts (Table 8).

 

Table 7.  Number of offspring per adult assigned to each parental type and relative reproductive success (offspring per parent) of hatchery (HOR) and natural (NOR) origin adults spawning naturally in Abernathy Creek  (reproductive success analyses were not performed in 2006).

Brood Year	Life History	Number of offspring per adult		Relative reproductive success of HOR compared to NOR
		HOR	NOR
2005	Total	1.40	5.83	0.24
2007	Anadromous	0.20	4.33	0.05
	Resident	0.19	0.18	1.06
	Total	0.19	0.45	0.42
2008	Anadromous	0.82	8.50	0.10
	Resident	0.02	1.45	0.01
	Total	0.38	3.55	0.11
2009	Anadromous	0.92	1.02	0.90
	Resident	0.00	0.10	0.00
	Total	0.21	0.40	0.52

 

The past two years of data have allowed (2008 and 2009) reproductive success to be assessed by family type as well as by parent of origin in order to evaluate the effect of HOR/NOR interbreeding (Table 8). Results indicate that HORxHOR crosses have lower reproductive success than natural NORxNOR crosses and crosses involving a HOR female and a NOR male (HORxNOR).  The reproductive success of NOR female by HOR male (NORxHOR) crosses was very different between the two years (Table 8).  These results appear to suggest there may be some selective disadvantage to crosses of mixed origin, but making a global statement about fitness based on family type would be inappropriate given the small sample sizes and variation in the results.  Additional data from 2010 and 2011 may clarify these results.

 

Table 8.  Relative reproductive success by family type for hatchery origin (H) and natural origin (N) adults spawning naturally in Abernathy Creek. Maternal origin is listed first.

Brood Year	Number of offspring per family				Reproductive success of HxH families relative to each cross
	HxH	NxN	NxH	HxN	NxN	NxH	HxN
2008	10.00	13.90	2.70	6.50	0.72	3.70	1.54
2009	1.30	2.30	8.00	1.00	0.57	0.16	1.30

 

Although an estimate of juvenile (parr or smolt) steelhead production from natural spawning adults was also requested by the ISRP, extrapolation of the offspring per family estimates to parr or smolt production in the system has not been conducted due to low assignment rates and small sample sizes of PIT tagged steelhead, and the associated high variance in these estimates.  Smolt samples for this project were obtained from WDFW which operated a screw trap each spring below AFTC near the mouth of Abernathy Creek.  HOR smolts were released from AFTC during the time of the outmigration of NOR smolts, so fish caught at the smolt trap included both NOR and HOR smolts.  In addition, due to the screw trap’s location below the electrical barrier weir, the offspring of any spawning that occurred below the AFTC weir were also passed through the trap.  NOR parr were caught in electrofishing surveys of Abernathy Creek each fall as part of this project.  However, this sampling routine was intended to assess residualization of HOR smolts and to capture NOR fish for PIT tagging rather than assess total juvenile abundance, so data with which to estimate parr production per family has not been determined.  Thus this estimate is dependent upon PIT tagged fish that have been assigned a parent.  Given that only a handful of fish meet both these requirements coupled with large variance it has been difficult to determine this estimate with any confidence.  Nevertheless, if sample sizes permit we may be able to estimate parr or smolt production by family type in future years for the study area located above the electrical barrier weir.  In our proposal we have included an effort to increase our sample size by effectively doubling our electrofishing and marking efforts.

 

We agree that the proposal and presentation appear to have contradictory statements; we have added or altered text to more accurately reflect and clarify the unique results of our study.  For example, our results suggested that smolt production had declined within all three creeks (F₅, ₁₈ = 8.7, P < 0.05), and there had been no significant increase or decrease in smolt yield due to supplementation in Abernathy Creek (Stream × Treatment Interaction: F₅, ₁₈ = 1.43, P = 0.26) as compared to control streams.  As a result, we conclude that smolt production has not been negatively affected by hatchery supplementation. 

 

In the second example in the accomplishment section within the proposal, it was our intent to suggest that a specific mechanism such as improper synchrony of chloride cell development at the time of progeny release (i.e. osmoregulatory ability) may be differentially affecting residual rates and survival.  Osmoregulatory ability may be a mechanism that is mandating that fish die or residualize in the system.  Those that do survive and become residents may negatively impact NOR fish but only for brief periods of time at specific locations within the creek.  Nevertheless, we have altered the text to help clarify and reduce the appearance of contradictory statements.

 

Primary Item 2:

 

We agree, the comparisons of adult steelhead abundance between Abernathy Creek (treatment) and Germany and Mill creeks (controls) are logistically difficult.  Water levels are too high and streams are too turbid to accurately conduct behavioral observations from the shore or via snorkeling.  Constructing permanent barriers on Germany and Mill creeks similar to the electric barrier on Abernathy Creek is cost prohibitive.  Steelhead redd counts on Abernathy, Germany and Mill creeks remain the only viable option for estimating relative adult abundance.  However, adult redd counts and their associated estimates operate on various assumptions; capturing adults using a picket weir may help to refine redd count assumptions.  As a result, we have come to an accord with WDFW (Mara Zimmerman); WDFW will operate an adult picket weir at the mouth of Abernathy Creek in order to help refine demographic characteristics for adult steelhead returns such as sex ratio, age structure, and redds per female.  The refined estimates will be applied to all three creeks (treatment and two control streams).  We argue that since redd counts are conducted by the same crews at the same time of year on all three creeks, any error in redd count data will be homogeneous among the streams.  Therefore significant differences in adult returns due to hatchery supplementation will be apparent and valid.  We have added an objective and increased the budget accordingly in order to accomplish this ISRP recommended task.  The results provided from this objective combined with the genetic analyses should yield scientifically defensible information that can be applied to all future data and may be used to rigorously analyze past data. 

 

In regards to the habitat restoration activities planned for the creeks, they remain only plans.  Habitat restoration activities such as riparian projects such as sapling plantings will take years if not decades to impart any significant change to population demographics, well beyond the duration of this study.

 

We believe that the additional objective will provide us with the ability to use demographic analyses to assess and interpret relative reproductive success and demographic consequences of supplementation.  As stated in the proposal, this study includes an evaluation of changes in production, demography, and genetic structure within Abernathy Creek and in reference to two control streams, Mill and Germany creeks. In line with these objectives, an evaluation of the level of gene flow between Abernathy Creek and the two control streams was done using 19 microsatellite loci (2009 Annual Report). The analysis included five years of smolt samples from Abernathy Creek (2002-2009), three years of smolt samples from Germany Creek (2002-2004) and four years of smolt samples from Mill Creek (2002-2005). A neighbor-joining dendogram (Figure 1) depicting the relationships among the creeks showed no evidence of major changes in the genetic structure of Abernathy Creek relative to Mill and Germany creeks, and only two branches of the tree (2008 Abernathy and 2008 Germany) and 2002 and 2003 Mill Creek samples had significant bootstrap values.

 

 

 An additional analysis (2009 Annual Report) using 9 microsatellite loci showed Abernathy, Mill, and Germany creeks are part of a larger group of five genetically similar populations in the Lower Columbia River (Grays River, Elochoman River, Abernathy, Mill, and Germany creeks) which is distinct from a group of populations of winter steelhead farther upriver (Coweeman River, Green River, Kalama River, East and North Fork Lewis Rivers, North and South Fork Toutle Rivers, Washougal River). Genetic divergence among Abernathy, Mill and Germany creeks (F_ST =0.006) was not significantly different from divergence among the Elochoman and Grays River collections (F_ST=0.003, Weir and Cockerham, 1984). These results indicate that the three populations are genetically similar and that the divergence among them is comparable to that found among other populations in the Lower Columbia River (USFWS 2009).

 

The results of these analyses indicate that the there is a large amount of gene flow among the three streams, which likely represent a single panmictic population rather than three independent genetic groups.  Although no strong genetic changes have been observed in the Abernathy Creek population relative to the other two since 2002 (USFWS 2009), our power to detect such changes is severely limited by the level of geneflow; any changes in the genetic structure of the Abernathy Creek steelhead due to hatchery supplementation are likely to affect that of steelhead in the other two creeks.

 

While our reports to date have not assessed changes in numbers of adult returns in Mill and Germany creeks, the inclusion of redd counts obtained from WDFW as a measure of population size in 2011 will allow us to compare changes in adult returns among the three creeks and assess any effect the supplementation program in Abernathy Creek has had on spawning population size. In 2011 additional smolt samples will also be collected from Mill and Germany creeks in order to update the baseline for the two populations. Additional analysis of these collections will assess patterns in genotypic disequilibrium, deviations from Hardy-Weinberg equilibrium and allelic richness relative to Abernathy Creek. Although these analyses will provide some insight into changes in the other two creeks relative to our “treatment” population, it is important to note that genetic results presented in 2009 and reiterated above indicate the three streams function as a single population, so changes observed in Mill and Germany creek population dynamics are unlikely to be independent of those observed in Abernathy Creek.

 

References

 

Cavalli-Sforza, L.L., and Edwards, A.W.  1967.  Phylogenetic analysis. Models and estimation procedures.  American Journal of Human Genetics 19:233-257.

 

Saitou, N. and Nei., M.  1987.  The neighbor-joining method: a new method for reconstructing phylogenetic trees.  Molecular Biology and Evolution 4: 406-425.

 

U.S. Fish & Wildlife Service, Abernathy Fish Technology Center, 1440 Abernathy Creek Road Longview, WA 98632.  2005.  Natural Reproductive Success and Demographic Effects of Hatchery-Origin Steelhead in Abernathy Creek, Washington Annual Report January 2005 – December 2005. (BPA Project No. 2003-063-00, Contract Number No. 016522).

 

U.S. Fish & Wildlife Service, Abernathy Fish Technology Center, 1440 Abernathy Creek Road Longview, WA 98632.  2007.  Natural Reproductive Success and Demographic Effects of Hatchery-Origin Steelhead in Abernathy Creek, Washington Annual Report January 2007 – December 2007. (BPA Project No. 2003-063-00, Contract Number No. 016522).

 

U.S. Fish & Wildlife Service, Abernathy Fish Technology Center, 1440 Abernathy Creek Road Longview, WA 98632.  2008.  Natural Reproductive Success and Demographic Effects of Hatchery-Origin Steelhead in Abernathy Creek, Washington Annual Report January 2008 – December 2008. (BPA Project No. 2003-063-00, Contract Number No. 016522).

 

U.S. Fish & Wildlife Service, Abernathy Fish Technology Center, 1440 Abernathy Creek Road Longview, WA 98632.  2009.  Natural Reproductive Success and Demographic Effects of Hatchery-Origin Steelhead in Abernathy Creek, Washington Annual Report January 2009 – December 2009. (BPA Project No. 2003-063-00, Contract Number No. 016522).

 

Weir, B. S. and Cockerham, C. C.  1984.  Estimating F-statistics for the analysis of population structure.  Evolution 38: 1358-1370.