Olympic Peninsula Steelhead Response to Peer Review

We received comments regarding the draft Biological Status of Olympic Peninsula (OP) Steelhead Distinct Population Segment (DPS) from two reviewers: Jonathan Moore PhD and Mike Haggerty. We also solicited a number of additional reviewers; however, due to prior obligations and time limitations we were unable to obtain additional reviewers.

In this document we provide responses to substantive comments by the reviewers, stylistic and grammatical comments, or typographical errors are not included. Reviewers’ comments, in their entirety, are provided in the Appendix.

Comment 1

The Status Review Team’s (SRT’s) identification/designation of distinct summer-run populations was questioned. In the absence of clear, temporal migratory barriers (as is found in Puget Sound and the Lower Columbia River DPSs), an alternative population structure with summer-run and winter-run steelhead being components of single population was suggested by a reviewer.

Response

Although rivers in the OP DPS do not have clear barriers that create temporal migratory windows, ecological differences between headwater and mainstem/lower basin reaches provide the basis for the life history differences that distinguish winter- and summer-run steelhead. While the SRT did not have the genetic data or spawner distribution for summer-run populations, the persistence of these distinct life-histories suggests some mechanism for reproductive isolation. The SRT recognized these life history differences as the primary diversity component in the DPS.

Comment 2

In defining the DPS and evaluating risk, the SRT did not specifically identify multiple small independent tributaries that contain steelhead.

Response

The SRT did not specifically identify smaller steelhead bearing streams. In part, this was related to the paucity of data related to these systems. The SRT did recognize that steelhead distribution is widespread in the accessible waters of the DPS, and certainly did not consider non-censused areas as vacant for the VSP risk analysis, especially spatial structure scoring. In the absence of demographic data, it was not possible to conclude whether these small steelhead aggregations were independent populations or demographically linked to nearby populations. Alternatively, as in the Strait of Juan de Fuca, where abundance data were available, we assessed these as independent units.

Comment 3

The SRT’s interpretation of the genetic results, specifically the detection of introgression by hatchery-origin steelhead, could instead be a sampling issue, that the fish sampled included stray first-generation hatchery-origin steelhead and not hatchery x natural hybrids, and that the small size of some samples and various dates of sampling (some samples were 20 years old) will affect the genetic analysis and add uncertainty to any conclusions. More genetic sampling was recommended.

Response

Hatchery-origin (adipose fin clipped) steelhead have been observed during snorkel surveys in reaches upstream from hatcheries or in tributaries that do not have hatcheries. More directly, genetic analysis (structure plots) indicates that some fish have equal or near equal genetic contributions from natural and hatchery-origin steelhead populations. This would equate to F1, F2, or similar hybrids.

The number of individuals sampled at some locations was very small in some instances and many samples were over ten years old. The SRT attempted to incorporate as much genetic data as were available. In most cases these samples provided a cohesive picture of the genetic structure of the DPS and surrounding areas. Samples that were outliers to the general genetic structure of the DPS were examined to understand potential factors that could influence the results (i.e., hatchery introductions).

The SRT agrees that more genetic sampling is needed to better understand the dynamics of the DPS; however, within the timeframe of this review additional sampling and genetic analysis was not possible. Additionally, available NMFS guidance for status reviews notes that usually new empirical studies would not be conducted during a status review, as the ESA requires the use of the “best scientific and commercial data available”, and also as there is an established time limit for completing status reviews.

Comment 4

Hatchery-origin summer run steelhead spawn timing is more separate from natural-origin summer than is suggested by the SRT report.

Response

The hatchery summer-run steelhead egg-take timing reported by the reviewer is not necessarily representative of full range of spawn timing (spawning to meet egg take quota). Furthermore, temperature conditions in the hatchery are likely not the same as those in headwater reaches and may influence the maturation and spawn timing of hatchery-origin steelhead. The SRT report relied on information documenting the presence of both natural and hatchery (clipped) summer run steelhead in freshwater holding pools, this co-occurrence indicates that introgression is possible. Finally, as discussed in the report, even if hatchery and natural female spawn timing (redd construction) is distinct, males linger on the spawning grounds and generally are available to spawn with later spawning females.

Comment 5

The SRT’s interpretation of smolt survival data from co-manager reports was inaccurate.

Response

Smolt to adult survival is an important life cycle phase in determining the productivity of populations and the DPS overall. Smolt to adult survivals were estimated in a co-manager report for natural and hatchery steelhead populations along the Washington coast. While not a designed study, the SRT concluded that it was informative, and suggested that hatchery smolt to adult survivals have been decreasing over time. Data for natural populations were limited, but did not show such a marked decline. This information was assessed in the context of other data sources in order to gain a more comprehensive picture of the status of populations in the DPS.

In an earlier SRT draft the natural smolt survival had been described as increasing, this was changed to stable.

Comment 6

The pre- and post-Busby comparisons should exclude the “Lowlands” populations category.

Response

In the two time periods the single data series for the Lowlands was represented by different rivers, and does not represent an apples-to-apples comparison for that category. We provided this caveat in the text and did not believe that data for this lightly represented category should be removed.

Comment 7

The SRT’s analysis of intrinsic growth rates and harvest for Strait of Juan de Fuca populations is not valid.

Response

This was a generalized attempt to estimate population growth rates and the effect of harvest. That changes in, and specific harvest conditions, introduce some uncertainty is understandable. The reviewer lists some factors, but there are others such as hooking mortality (non-retention fisheries still introduce mortality). The reviewer also suggests tribal gillnet fisheries were intercepting steelhead in some years and basins (for which we had no record). This limits but does not exclude our using patterns of harvest to examine population trajectories.

Comment 8

The SRT’s description of fisheries management is misrepresented in the Review, the fishery is not “wide-open.” Also, the SRT did not acknowledge the recent decrease in harvest rates.

Response

The SRT did not describe the fishery as wide-open, but there was considerable concern regarding the high harvest rates documented for the four major basins (Quillayute, Hoh, Queets, and Quinault Rivers) up until the last few years. Escapement goals based on freshwater juvenile production were identified by the co-managers; however, the SRT’s analysis also included run size, where possible, and it was the maintenance of high harvest rates in light of declining runs sizes that was seen as an indicator of more risk. This conclusion was also expressed by WDFW in Harbison et al. (2022).

The SRT did acknowledge the decrease in harvest rates over the most recent few years and based on the reviewer’s comments rephrased and restructured a section to better highlight this decrease in harvest; however, the SRT was concerned that the demographic response to these reductions was slight if any at all (although only a few years had passed since the reductions) and that there was no certainty that rates would stay low. The SRT Report also underscored how harvest is now largely eliminated from the populations along the Strait of J9an de Fuca.

Comment 9

The SRT’s description of bycatch was not clear.

Response

This section was rewritten to emphasize that there were no data available for the harvest of juvenile and adult steelhead in non-steelhead fisheries. This would have included summer and fall salmon seasons and recreational trout fish fishing.

Comment 10

The SRT identified recreational summer-run steelhead harvest as a continuing issue when there is no fishery for summer run steelhead.

Response

The SRT provided summer-run harvest data (past and current) for several reasons: 1) to underscore that previously there had been considerable numbers of summer-run steelhead harvested, equal to or greater than current population estimates, 2) even though summer-run steelhead retention has been prohibited, summer-run catches are still occasionally recorded on punch cards, 3) recreational catches are still likely during the summer by fishers targeting other species – even with non-retention, hooking mortalities could be considerable during the summer months.

Comment 11

The SRT’s description of a shift in natural-origin winter steelhead run was inaccurate. One reviewer did not consider the compression in run timing as a loss of diversity. Further the reviewer expressed that the SRT’s interpretation of the contribution of harvest to described changes in run timing is also unfounded.

Response

Response: The SRT considered that a decrease in run timing variability is a diversity issue, especially if that change is directional. There is substantial evidence that run timing is a heritable trait, and harvest (whether it is directed on hatchery fish or not) can be a selective factor. It is not necessary, as the reviewer states, that one needs to know the CPUE to evaluate this selective factor if one knows the proportion of the population that is being selected.

Comment 12

One reviewer stated that stable escapement and reduced recruitment “can be entirely explained by reduce productivity for maiden recruits and increased mortality rates for repeat spawners.”

Response

The SRT provided those factors as two of the several potential factors limiting productivity.

Comment 13

One reviewer stated that the SRT’s evaluation of hatchery programs was decidedly negative and presented no positive benefits. Further, the SRT’s proportion hatchery spawners data (pHOS) was quite dated and, in some cases, based solely on professional opinion.

Response

One task of the SRT is to provide a risk of extinction evaluation through the viable salmonid population (VSP) process. Given the fact that all of the steelhead hatchery stocks used in the Olympic Peninsula DPS are either founded by out-of-DPS stocks or have been widely influenced by transfers of out-of-DPS stocks, there is no basis from an extinction risk standpoint to consider hatchery programs as a benefit. Clearly, there are cultural, societal, and economic benefits to these programs, but those are not considered by the SRT in the status review process.

The pHOS data presented in the Review was provided to the SRT with a number of caveats. As in many other situations, because of the limited nature of some information, the SRT relied on multiple data sources and types to provide an understanding of population and DPS status.

Older pHOS data is still relevant to the discussion of hatchery effects and diversity. The legacy of genetic introgression continues for generations unless selected out of the population. The SRT relies on the data that is available, that there are no recent pHOS estimates for many populations was also considered a regulatory deficiency.

Comment 14

One of the reviewers asserted that the SRT statement that the reduction in hatchery smolt survival underscores risk of introgression is not necessarily supported by the data. The reviewer points to the differences in survival from 1.8% (1988) to 10% (2007) to illustrate a change in fitness.

Response

The report cited that indicates hatchery smolt survival is declining, while natural smolt survival is stable, suggests that there may be long-term consequences from hatchery domestication (although the data set is limited). If so, integrating hatchery genes, through hybridization, into the natural population would reduce the fitness. Clearly, spcific year-to-year comparisons reflect a variety of environmental conditions (freshwater, ocean, hatchery), but the SRT considered longer term trends in survival which smooths out many effects.

Comment 15

One of the reviewers asserted that steelhead harvest-based risk was overemphasized and habitat ignored.

Response

The SRT discussed both legacy and ongoing land-use practices at length, especially as they related to timber activities. Although the watershed function appears to be generally good throughout the DPS and there has been improved regulatory oversight on timber harvest, activities in the industrial forest lands continue to negatively affect the habitat quality in many areas. Forestry roads also have continuing effects, and culverts at stream crossings have an effect on spatial structure and habitat quality. Habitat restoration efforts were also discussed in some detail, noting areas where culverts had been replaced and riparian habitat restored. It was also underscored that habitat recovery generally occurs over decades.

Similarly, present and future habitat quality was addressed in the context of ongoing climate change effects.

Appendix

Comments from Jonathan Moore PhD (PDF, 5 pages)

Comments from Mike Haggerty (PDF, 24 pages)