Proxies for estimation of relative fishing mortality when biomass is unknown

Froese, Rainer and Sampang, A. (2012) Proxies for estimation of relative fishing mortality when biomass is unknown [Paper] In: ICES Annual Science Conference 2012, 17.-21.09.2012, Bergen, Norway.

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The Marine Strategy Framework Directive proposes two indicators for assessing the level of pressure of fishing activities on the target species. The primary indicator is the fishing mortality (F) relative to the one (Fmsy) that will eventually lead to the maximum sustainable yield. The secondary indicator is the catch/biomass ratio relative to a catch/biomass proxy for Fmsy. Both indicators and their reference points need biomass of the target stock to be known. Biomass is, however, unknown for the majority of fish stocks in European waters. Fish grow throughout their lives, and the mean size they reach is a function of their average rate of total mortality over the past years, roughly equal to generation time. This presentation proposes mean length in the commercial catch and the von Bertalanffy growth parameter K or the rate of natural mortality as reasonable proxies for F and Fmsy, respectively. These proxies will be evaluated against respective estimates derived from full stock assessments.

Document Type: Conference or Workshop Item (Paper)
Keywords: Marine Strategy Framework Directive, proxies for fishing pressure
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EV Evolutionary Ecology of Marine Fishes
Date Deposited: 26 Nov 2012 11:54
Last Modified: 06 Jan 2017 10:45

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