Obiettivo
Current fish stock assessment is based primarily on fisheries data (catches/landings) and models of population demography (cohort analysis). Collapse of important fish stocks in the past (e.g. cod in Canada) have revealed that fisheries based demographic indices suffer from a number of limitations. Probably the most serious limitation is that the indication of population collapse is only perceived very late with such indices, in comparison with other biological indices.
The purpose of this project is to develop fish stock assessment tools based on survey data only and evaluate how these perform in producing advice within defined management procedures. The project spans several disciplines (i.e. population biology, survey methods, stock assessment, management), with the objectives of (1) producing a comprehensive diagnostic of population status using survey-based population demography and biological indices and (2) evaluate its performance in a management context.
A variety of methods is proposed to obtain direct estimates (and associated errors) of population abundance, mortality, spatial occupation and maturity at age. Direct demographic estimates feed assessment population models to deliver model-based estimates of abundance, survey catchability, natural and fishing mortality. Different categories of population assessment models are developed for to different biological situations. The simplest models track the dynamics in total abundance while others are age or length structured. The assessment procedure is evaluated by simulation testing using a framework containing a population dynamics model, an observation model, an assessment model and an harvest rule model. The ability of the assessment procedure to capture changes in population biology and survey catchability is evaluated. The sensitivity of the assessment procedure to uncertainties in survey estimates is also tested, so that alternative survey designs can be explored...
Campo scientifico
Invito a presentare proposte
FP6-2002-SSP-1
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Meccanismo di finanziamento
STREP - Specific Targeted Research ProjectCoordinatore
ISSY-LES-MOULINEAUX
Francia