An empirical weight-at-age approach reduces estimation bias compared to modeling parametric growth in integrated, statistical stock assessment models when growth is time varying

Kuriyama, Peter T.; Ono, Kotaro; Hurtado-Ferro, Felipe; Hicks, Allan C.; Taylor, Ian; Licandeo, Roberto; Johnson, Kelli F.; Anderson, Sean C.; Monnahan, Cole C.; Rudd, Merrill B.; Stawitz, Christine C.; Valero, Juan L.

doi:10.1016/j.fishres.2015.09.007

Cited by 13 publications

(5 citation statements)

References 88 publications

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“…Time-varying growth is speculated to have a significant effect on the population dynamics and overall biomass of a stock (Shin & Rochet, 1998;Rice, 2011) and it is increasingly suggested that plasticity of growth be recognised and accounted for in stock assessment and fisheries management (Kuriyama et al, 2016;Lorenzen, 2016;Stawitz, Haltuch & Johnson, 2019) as it can have potentially large and farreaching consequences for management decisions. The results of our Bayesian models are similar to those found by Thorson and Minte-Vera (2016) who performed a similar analysis on 25 species of marine fishes and found that a majority of them exhibited variation in year effects for growth.…”

Section: Discussionmentioning

confidence: 99%

“…The concept of growth is central to fisheries manage ment and stock assessment procedures (Sparre & Venema, 1998). Historically, time-varying growth in stock-assessment models has been included as either empirical mass or length at age (Kuriyama et al, 2016;Lorenzen, 2016), but the recent push towards using integrated assessments recommends internally modelling as many processes as possible (Maunder & Punt, 2013). Within integrated assessments where growth is modelled internally the temporal variation in growth is often not taken into account (Stawitz, Haltuch, & Johnson, 2019).…”

Section: Introductionmentioning

confidence: 99%

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Drivers of growth for Atlantic cod (Gadus morhua L.) in Icelandic waters – A Bayesian approach to determine spatiotemporal variation and its causes

Frater

Hrafnkelsson

Elvarsson

et al. 2019

Journal of Fish Biology

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This study assesses spatiotemporal and sex‐specific growth of Atlantic cod Gadus morhua in Icelandic waters. We use a Bayesian approach which lends itself to fitting and comparing nested models such as these. We then compare fitted parameters of these models to potential explanatory variables using a redundancy analysis (RDA) to look for drivers of growth in G. morhua. Results indicate that models that incorporate differences in growth among time, space and sex are the best‐fitting models according to deviance information criterion (DIC). Results from RDA indicate that capelin Mallotus villosus recruitment and biomass is highly correlated with deviations in the von Bertalannfy growth parameter k and that L∞ is correlated with G. morhua landings in the model that uses year to account for time‐varying growth and estimated G. morhua recruitment in the model that uses cohort to account for time‐varying growth.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Drivers of growth for Atlantic cod (Gadus morhua L.) in Icelandic waters – A Bayesian approach to determine spatiotemporal variation and its causes

Frater

Hrafnkelsson

Elvarsson

et al. 2019

Journal of Fish Biology

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“…Bias in selectivity estimates can occur if data are pooled from stocks that have different responses to temperature (e.g. Concerns about changes in growth may be less important for assessment models (such as some cohort analyses) that use annual empirical information about weight-at-age rather than fitted and assumed growth curves (but data quality and quantity are critical, see Kuriyama et al 2015). A 20% underestimate in VB k will lead to ca 20% reduction in the estimation of yield-per-recruit biomass at fishing mortality F 0.1 (year À1 ) (the F value where the curve of production against fishing morality has a gradient of 10%) (Pardo et al 2013).…”

Section: Impact Of Life-history Trends In Single Species Managementmentioning

confidence: 99%

“…A 20% underestimate in VB k will lead to ca 20% reduction in the estimation of yield-per-recruit biomass at fishing mortality F 0.1 (year À1 ) (the F value where the curve of production against fishing morality has a gradient of 10%) (Pardo et al 2013). Concerns about changes in growth may be less important for assessment models (such as some cohort analyses) that use annual empirical information about weight-at-age rather than fitted and assumed growth curves (but data quality and quantity are critical, see Kuriyama et al 2015). However, even for stocks managed using such models and data, projections about future stock dynamics may become biased if possible trends in growth and maturation are not considered.…”

Section: Impact Of Life-history Trends In Single Species Managementmentioning

confidence: 99%

Trends and management implications of human‐influenced life‐history changes in marine ectotherms

et al. 2016

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Evidence is accumulating that many marine ectotherms are undergoing rapid changes in their life‐history characteristics. These changes have been variously attributed to fisheries‐induced evolution, inhibited adult growth rate due to oxygen limitation at higher temperatures, and plastic responses to density dependence or changes in ocean productivity. Here, we review the diverse underlying mechanisms by which plastic and evolutionary responses to climate change and fisheries are likely to produce similar life‐history trends in harvested marine ectotherms, leading to faster life‐histories with earlier maturation and smaller adult size‐at‐age. While mechanistically understanding these growth and maturation changes may be difficult, it is becoming clear that changing life‐histories will lead to modified population dynamics, productivity and natural mortality of the affected species. We discuss how the observed and expected life‐history changes could affect the assumptions and uncertainty within single and multispecies models currently used in marine ecosystem management, highlighting that models which allow for dynamic life‐history traits often report significantly different estimates of stock biomass. Given that both climate‐ and harvest‐induced life‐history changes are likely to intensify and possibly amplify each other, there is an urgent need to adequately assess the implications of faster life‐histories for marine ecosystem management. This is especially true for data‐poor stocks, where growth and maturation are not regularly assessed. Targeted monitoring can be used to inform responsive management, but for improved sustainability outcomes, a precautionary approach to management that is robust to life‐history trends is advised.

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“…Unfortunately, no recent population parameter values are available in the literature, so it is assumed that the values in Table 1 are valid. However, it has been suggested that "empirical weight-at-age approach is best applied to data-rich stocks for which growth is a difficult process to characterize" [15][16][17]. Estimates of growth rate, length-weight relationship, and natural mortality are necessary to transform catch data into number of organisms by age.…”

Section: Stock Dynamics and Assessmentmentioning

confidence: 99%

Assessing the Exploitation Strategies of the Shrimp Fishery in the Gulf of California

RamÃÂrez-Villalobos¹,

ChÃ¡vez²

2020

Fish Aquac J

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Shrimp is the most valuable fisheries resource in Mexico, representing almost 40% of the total production landed, with total revenue of more than US $ 132 million per year. Shrimp fishery provides with more than 30,000 direct and indirect jobs. Three peneid shrimp species, blue, brown, and white shrimp of the southern Gulf of California, are exploited near to their maximum capacity, and they account for >95% of the wild stock of the Pacific coast. In the current fishery, the age of first capture is the overexploiting juveniles; therefore, increasing the age of the first capture from four to five months is recommended. The stocks were evaluated with a simulation model. Two fishing scenarios were tested: the maximum sustainable yield (MSY) and the MSY/fisher. As it is not possible to address particular exploitation policies for each species, the recommended exploitation strategies are based on combined species. It was concluded that, for the MSY scenario, 12,000 fishing days per season would fulfill most of the requirements; in the second case (MSY/fisher), reducing the current number of boats to 530 would achieve the required goal.

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An empirical weight-at-age approach reduces estimation bias compared to modeling parametric growth in integrated, statistical stock assessment models when growth is time varying

Cited by 13 publications

References 88 publications

Drivers of growth for Atlantic cod (Gadus morhua L.) in Icelandic waters – A Bayesian approach to determine spatiotemporal variation and its causes

Drivers of growth for Atlantic cod (Gadus morhua L.) in Icelandic waters – A Bayesian approach to determine spatiotemporal variation and its causes

Trends and management implications of human‐influenced life‐history changes in marine ectotherms

Assessing the Exploitation Strategies of the Shrimp Fishery in the Gulf of California

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