Handle with Care: Establishing Catch Limits for Fish Stocks Experiencing Episodic Natural Mortality Events

Harford, William J.; Grüss, Arnaud; Schirripa, Michael J.; Sagarese, Skyler R.; Bryan, Meaghan D.; Karnauskas, Mandy

doi:10.1002/fsh.10131

Cited by 14 publications

(8 citation statements)

References 26 publications

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“…These studies focus on freely estimating varying natural mortality (i.e., without ancillary data). Other studies have more explicitly attributed variation in mortality to predation (Trijoulet et al 2020), mass die-offs due to environmental phenomena (e.g., red tides; Harford et al 2018), or biological theory (e.g., as it relates to size and growth, or the "U-shape" assumption across ages; Chu et al 2008;Gislason et al 2010;Lorenzen 1996). Impacts of infectious diseases have been largely ignored in this body of literature.…”

Section: Discussionmentioning

confidence: 99%

A novel approach for directly incorporating disease into fish stock assessment: a case study with seroprevalence data

Trochta

Groner

Hershberger

et al. 2022

Can. J. Fish. Aquat. Sci.

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When estimating mortality from disease with fish population models, common disease surveillance data such as infection prevalence are not always informative, especially for fast-acting diseases that may go unobserved in infrequently sampled populations. In these cases, seroprevalence — the proportion of fish with measurable antibody levels in their blood — may be more informative. In cases of life-long immunity, seroprevalence data require less frequent sampling intervals than infection prevalence data and can reflect the cumulative exposure history of fish. We simulation tested the usefulness of seroprevalence data in an age-structured fish stock assessment model using viral hemorrhagic septicemia virus (VHSV) in Pacific herring (Clupea pallasii) as a case study. We developed a novel epidemiological model to simulate population dynamics and seroprevalence data and fitted to these data in an integrated catch-at-age model with equations that estimate age- and time-varying mortality from disease. We found that simulated seroprevalence data can provide accurate estimates of infection history and disease-associated mortality. Importantly, even models that misspecified nonstationary processes in background or disease-associated mortality, but included seroprevalence data, accurately estimated annual infection and population abundance.

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Section: Discussionmentioning

confidence: 99%

A novel approach for directly incorporating disease into fish stock assessment: a case study with seroprevalence data

Trochta

Groner

Hershberger

et al. 2022

Can. J. Fish. Aquat. Sci.

View full text Add to dashboard Cite

show abstract

“…This scenario, the stock is at a higher biomass level at the start of the management period (250%

B_{MSY}^{S}

). Episodic M—evaluated the MPs when the operating model diverges from the assumptions of the assessment model and projections during the management period. Environmental conditions can reduce population abundance through episodic events, for example, die‐offs (Anderson, Branch, Cooper, & Dulvy, 2017; Harford et al, 2018). Here, we model die‐offs through episodic increases in natural mortality.…”

Section: Methodsmentioning

confidence: 99%

The interim management procedure approach for assessed stocks: Responsive management advice and lower assessment frequency

et al. 2020

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Stock assessments are often used to provide management advice, such as a total allowable catch (TAC), to fishery managers. Many stocks are not assessed annually, and the TAC from the previous assessment is often maintained in years between assessments. We developed two interim management procedures (MPs) that update the estimate of current vulnerable biomass from a surveyed index of abundance to adjust the TAC from a previous assessment. These MPs differ in how they handle uncertainty in observed indices. Using closed-loop simulation, we evaluated the two interim MPs (with 10-and 5-year assessment intervals) against several "status quo" approaches: (1) an annual assessment, and (2) a stock assessment every 5 or 10 years with (a) fixed TACs or (b) projections between assessments. We evaluated performance across three life-history types and six operating model scenarios. The interim MPs performed similarly to annual assessments in terms of trends in biomass and yield, regardless of the assessment interval of the interim MPs. The interim MPs often produced more yield than the Fixed TAC MP with 10-year assessment intervals, for example, in depleted scenarios. The Fixed TAC MP performed more similarly to interim MPs when the assessment interval for the Fixed TAC MP was decreased to five years. The interim MPs can also perform well when circumstances arise that are not accounted for in the Projection MP. Our results show that interim MPs should be considered for infrequently assessed stocks or rebuilding stocks, and highlight potential cost savings of interim MPs over annual assessments. K E Y W O R D Sfisheries management, management strategy evaluation, simulation, stock assessment, total allowable catch

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“…We should not expect 'generic' HCR performance (e.g., Conceptual MP scenario) within the U.S. sandbar shark fishery. Further considerations in other systems may include significant ecosystem dynamics (e.g., red tide or climate change; Harford et al 2018;Holsman et al 2020), delays in data availability and fishery management implementation (e.g., Shertzer and Prager 2007), spatial or stock structure (e.g., Atlantic bluefin tuna, Carruthers and…”

Section: Conceptual Versus Expected Implementation Scenario Performancementioning

confidence: 99%

Effects of unregulated international fishing on recovery potential of the sandbar shark within the southeastern United States

Peterson

Wilberg

Cortés

et al. 2022

Can. J. Fish. Aquat. Sci.

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Coastal sharks are challenging to manage in the United States due to their slow life history, limited data availability, history of overexploitation, and competing stakeholder interests. Furthermore, species like the sandbar shark are subjected to international exploitation unmanaged by the U.S. We conducted a management strategy evaluation using Stock Synthesis on the sandbar shark to test the performance of various configurations of a threshold harvest control rule. In addition to uncertainties addressed in the operating model, we built multiple implementation models to address uncertainties related to future levels of a partially unmanaged source of removals, the combined Mexican and U.S. recreational (MexRec) fleet. We found that the presence of unregulated removals had the potential to significantly influence the success of the various management procedures tested. Notably, if MexRec catches continue to increase with total stock abundance following historical trends, the rate of MexRec removals will be too large to allow the sandbar shark to recover across operating models. We present trade-offs between performance metrics across a range of 24 management procedures and three implementation models.

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Handle with Care: Establishing Catch Limits for Fish Stocks Experiencing Episodic Natural Mortality Events

Cited by 14 publications

References 26 publications

A novel approach for directly incorporating disease into fish stock assessment: a case study with seroprevalence data

A novel approach for directly incorporating disease into fish stock assessment: a case study with seroprevalence data

The interim management procedure approach for assessed stocks: Responsive management advice and lower assessment frequency

Effects of unregulated international fishing on recovery potential of the sandbar shark within the southeastern United States

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