A Review of Salmon Spawner-Recruitment Analysis: The Central Role of the Data and Its Impact on Management Strategy

Adkison, Milo D.

doi:10.1080/23308249.2021.1972086

Cited by 3 publications

(3 citation statements)

References 260 publications

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“…The contrasting messages on the feasibility of coming close to maximizing natural productivity based on spawner-recruit relationships for the upper Sacramento River vs. the Sacramento River basin as a whole may reflect challenges and uncertainties in estimating these sorts of relationships (Adkison 2022). Additionally, or alternatively, that contrast could reflect an issue highlighted by PFMC (1984) where achieving sufficient escapement to fully seed the upper Sacramento may often require "over-escapement" to the lower watershed, because of the typical proportion of basin-wide escapement that returns to areas above RBDD.…”

Section: Discussionmentioning

confidence: 99%

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An Approach to Defining a Sacramento River Fall Chinook Escapement Objective Considering Natural Production, Hatcheries, and Risk Tolerance

Satterthwaite

2023

SFEWS

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The escapement objective used to manage fisheries on Sacramento River Fall Chinook (SRFC) was established in 1984. Despite substantial changes to the system and multiple calls to re-evaluate the objective, data and analytical limitations have slowed progress. Synthesizing the available information is further complicated by the different measurement scales employed by relevant studies. Here, I offer a modeling framework for integrating consideration of established hatchery spawning goals, natural-area production or habitat capacities measured at varying spatial scales, and policy decisions about what fraction of potential natural production is desired along with risk tolerance. The model allows evaluating how likely a potential escapement goal (measured at the currently-used scale of fall run adults returning to both hatcheries and natural areas throughout the Sacramento Basin) is to both meet hatchery goals and to produce at least a specified fraction of potential natural production. The framework also incorporates consideration of forecasting and harvest planning error into identifying a pre-season planning target and its probability of resulting in escapement at least as high as the goal. The model indicates that the low end of the current escapement goal range of 122,000-180,000 adults, if achieved, would be more likely than not to achieve hatchery goals while achieving around 50% of potential natural production. Realized escapement equal to the high end is modeled to be highly likely to achieve hatchery goals and likely to achieve around 75% of potential basin-wide natural production or around 60% of Upper Sacramento potential production. The model indicates diminishing returns from total adult SRFC escapements higher than about 300,000 adults. However, past performance of forecast and harvest planning models suggest that a preseason target higher than the ultimate escapement goal is needed to have even a 50% chance of achieving the escapement goal.

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Section: Discussionmentioning

confidence: 99%

“…Even with recruits measured at the desired scale, numerous challenges in fitting a stock-recruit relationship (in this and other systems), can be very demanding of the data (Adkison 2022).…”

Section: Caveatsmentioning

confidence: 99%

An Approach to Defining a Sacramento River Fall Chinook Escapement Objective Considering Natural Production, Hatcheries, and Risk Tolerance

Satterthwaite

2023

SFEWS

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“…Mark–recapture experiments, which are commonly used for fishery management (Adkison, 2022 ), traditionally rely on physically tagging individuals for population abundance estimation (Pradel, 1996 ). While these methods can provide reliable abundance estimates under specific conditions, meeting necessary assumptions is challenging, often resulting in reduced precision of abundance estimates (Roff, 1973 ).…”

Section: Introductionmentioning

confidence: 99%

Reliability of trans‐generational genetic mark–recapture (tGMR) for enumerating Pacific salmon

Rosenbaum,

May,

Shedd

et al. 2024

Evolutionary Applications

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As Pacific salmon (Oncorhynchus spp.) decline across much of their range, it is imperative to further develop minimally invasive tools to quantify population abundance. One such advancement, trans‐generational genetic mark–recapture (tGMR), uses parentage analysis to estimate the size of wild populations. Our study examined the precision and accuracy of tGMR through a comparison to a traditional mark–recapture estimate for Chilkat River Chinook salmon (O. tshawytscha) in Southeast Alaska. We examined how adult sampling location and timing impact tGMR by comparing estimates derived using samples collected in the lower river mainstem to those using samples obtained in upriver spawning tributaries. Results indicated that tGMR estimates using a representative sample of mainstem adults were most concordant with, and 3% more precise than, the traditional mark–recapture estimate for this stock. Importantly, the timing and location of adult sampling were found to impact abundance estimates, depending on what proportion of the population dies or moves to unsampled areas between downriver and upriver sampling events. Additionally, we identified potential sources of bias in tGMR arising from violations of key assumptions using a novel individual‐based modeling framework, parameterized with empirical values from the Chilkat River. Simulations demonstrated that increased reproductive success and sampling selectivity of older, larger individuals, introduced negative bias into tGMR estimates. Our individual‐based model offers a customizable and accessible method to identify and quantify these biases in tGMR applications (https://github.com/swrosenbaum/tGMR_simulations). We underscore the critical role of system‐specific sampling design considerations in ensuring the precision and accuracy of tGMR projects. This study validates tGMR as a potentially useful tool for improved population enumeration in semelparous species.

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Evaluation of management performance of a new state-space model for pink salmon (Oncorhynchus gorbuscha) stock–recruitment analysis

2023

Can. J. Fish. Aquat. Sci.

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A new state-space model (XSR) was developed to treat observation errors in spawner and catch data, and nonstationarity in productivity for pink salmon (Oncorhynchus gorbuscha). Closed-loop simulation was used to evaluate the management performance of XSR and compare its performance with that of a traditional stock-recruitment (SR) model (TSR) and a Kalman Filter SR model (KF). XSR produced higher expected catch than TSR and KF over a wide range of conditions. In some situations, TSR was preferred for reducing conservation concerns. However, large “outcome uncertainty" or implementation error in achieving desired management objectives can substantially reduce the management benefits of all assessment methods. Thus, outcome uncertainty should be considered in all management strategy evaluations, otherwise results will be misleading. Reducing outcome uncertainty may better help achieve objectives.

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A Review of Salmon Spawner-Recruitment Analysis: The Central Role of the Data and Its Impact on Management Strategy

Cited by 3 publications

References 260 publications

An Approach to Defining a Sacramento River Fall Chinook Escapement Objective Considering Natural Production, Hatcheries, and Risk Tolerance

An Approach to Defining a Sacramento River Fall Chinook Escapement Objective Considering Natural Production, Hatcheries, and Risk Tolerance

Reliability of trans‐generational genetic mark–recapture (tGMR) for enumerating Pacific salmon

Evaluation of management performance of a new state-space model for pink salmon (Oncorhynchus gorbuscha) stock–recruitment analysis

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