What Limits Clupeoid Production

Lasker, Reuben

doi:10.1139/f85-260

Cited by 75 publications

(38 citation statements)

References 5 publications

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“…En la literatura se pueden encontrar numerosos ejemplos hipotéticos de la influencia ambiental sobre la abundancia, a través del reclutamiento y/o crecimiento poblacional (Blaxter y Hunter, 1982;Lasker, 1985), tales como: influencia de la intensidad de la surgencia, relaciones entre la producción del stock y la descarga de los ríos, influencia de la temperatura durante un estadio crítico, entre otros (Tabla 1). Esquemáticamente se han identificado cuatro períodos o estadios críticos: -Antes del desove, influenciando la fecundidad del stock parental y/o el proceso de fecundación.…”

Section: Modelos Finalesunclassified

Influencia del medio ambiente en evaluación de stock: una aproximación con modelos globales de producción

Fréon¹,

Yáñez²

1995

Investig. mar.

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RESUMEN.Los modelos de producción convencionales no son adecuados para ciertos stocks, porque las variaciones del esfuerzo de pesca explican sólo una parte de la variabilidad total de las capturas anuales. A menudo la variación residual es originada por fenómenos ambientales, que afectan la abundancia y/o la capturabilidad del stock de un año a otro. En consecuencia, se ha incluido en los modelos convencionales una variable ambiental para mejorar la exactitud. Esta variable aparece en las fórmulas a nivel de la abundancia, de la capturabilidad, o de ambas. Estos modelos son desarrollados a partir del modelo de producción lineal de Schaefer, del exponencial de Fox o del generalizado de Pella y Tomlinson.CLlMPROD es un sistema-experto experimental que proporciona una descripción estadística y gráfica de los datos y permite la selección del modelo correspondiente según los criterios objetivos del usuario. El software ajusta los modelos usando rutinas de regresión no-lineal, evalúa el ajuste a través de tests paramétricos y no-paramétricos, y proporciona una representación gráfica de los resultados.Se consideran las limitaciones de este tipo de modelos. No obstante, éstos pueden proporcionar una interpretación bastante acertada de la historia de la pesquería, particularmente en el caso de stocks que colapsan inesperadamente sin ningún aumento apreciable del esfuerzo de pesca. Estos modelos también pueden ser útil en el manejo eficiente de este tipo de pesquerías, cuando los fenómenos climáticos pueden ser pronosticados o cuando su influencia esté restringida a la explotación del año(s) anterior. Finalmente se presenta el análisis de dos pesquerías colapsadas por una combinación de sobrepesca y cambios ambientales: la pesquería de sardina de Senegal y la de anchoveta del Pacífico suroriental.Palabras claves: evaluación de stock, modelos de producción, manejo, software, ambiente, sardina, anchoveta. The influence of environment on stock assessment:an approach with surplus production models ABSTRACT. Conventional global production models are not suitable for certain stocks, because fishing effort variations explain only a part of the total variability of annual catches. Often the residual variability originates from the influence of environmental phenomena, which affect either the abundance or the catchability of a stock from one year to the next. Therefore, an additional environmental variable has been inserted into conventional models in order to improve their aeeuracy. This variable appear in simple formulae concerning either stock abundance, or the catchability coefficient, or both. The models were developed from Schaefer's linear production model, Fox's exponential model or Pella and Tomlinson generalised model. CLlMPROD is an experimental expert-system, using artificial intelligence, which provides a statistical and graphical description of the data set and helps the user to select the model corresponding to his case according to objective eriteria. The software fits the model to the data set using a non-linear r...

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Section: Modelos Finalesunclassified

Influencia del medio ambiente en evaluación de stock: una aproximación con modelos globales de producción

Fréon¹,

Yáñez²

1995

Investig. mar.

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“…Trippel, 1998) and application of the egg production method to determine spawning stock sizes (e.g. Lasker, 1985).…”

Section: Biological Processes Affecting Survival During Different Lifmentioning

confidence: 99%

“…that produce multiple batches of eggs in one spawning season with successive recruitment of vitellogenic oocytes (Alheit, 1989). Although the daily egg production method (Lasker, 1985) Marshall et al, 2000).…”

Section: Realised Fecunditymentioning

confidence: 99%

“…walleye pollock , or highly fluctuating, e.g. the northern anchovy population off California (Lasker, 1985). In the latter case, the varying mortality rates were attributed to predation, e.g.…”

Section: Egg Survivalmentioning

confidence: 99%

“…cannibalism, as well as oceanographic processes, e.g. offshore transport (Lasker, 1985). In fact, there is considerable evidence that predation by invertebrates and fish can be a major source of mortality of pelagic and demersal fish eggs (for review see Heath, 1992;Leggett and DeBlois, 1994: newest evidence .…”

Section: Egg Survivalmentioning

confidence: 99%

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Scientific knowledge of biological processes potentially useful in fish stock predictions

2003

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SUMMARY: Based on an extensive review of available knowledge, several sources of information have been identified as potentially useful in fish stock predictions. They refer to a variety of biological processes of importance for stock dynamics, e.g. growth, maturation and egg production as well as early and juvenile life stage survival and subsequent recruitment, for which examples are given. Environmental variables impacting these processes were derived, ranging from simple statistical exploratory analyses to complex process studies for various stocks in different sea areas. Causal relationships are understood to varying degrees and in several cases the identified variables may only be taken as proxies for processes not investigated in detail yet. Besides the explanatory power of relevant variables, their predictability and related predictive time frames are of major importance for a potential application in stock predictions. These criteria in particular may hamper implementation in the foreseeable future in several cases. However, the information may still be highly relevant for a) hindcasting stock developments that are so far not fully understood, b) defining stock projection scenarios for simulation of different fishery management strategies under varying environmental conditions and considering species interactions and c) elucidating areas of future research to further enhance our predictive capabilities.

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Current Paradigms and Forms of Advice

Cochrane

2016

Fish Reproductive Biology

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What Limits Clupeoid Production

Cited by 75 publications

References 5 publications

Influencia del medio ambiente en evaluación de stock: una aproximación con modelos globales de producción

Influencia del medio ambiente en evaluación de stock: una aproximación con modelos globales de producción

Scientific knowledge of biological processes potentially useful in fish stock predictions

Current Paradigms and Forms of Advice

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