A two-stage biomass model to assess the English Channel cuttlefish (Sepia officinalis L.) stock

The English Channel cuttlefish (Sepia officinalis) is the most abundant cephalopod resource in the Northeast Atlantic and one of the three most valuable resources for English Channel fishers. Depletion methods and age-structured models have been used to assess the stock, though they have shown limit...

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Bibliographic Details
Published in:ICES Journal of Marine Science
Main Authors: Gras, Michael, Roel, Beatriz A., Coppin, Franck, Foucher, Eric, Robin, Jean-paul
Format: Article in Journal/Newspaper
Language:English
Published: Oxford university press 2014
Subjects:
SST
Online Access:https://archimer.ifremer.fr/doc/00248/35923/34448.pdf
https://doi.org/10.1093/icesjms/fsu081
https://archimer.ifremer.fr/doc/00248/35923/
Description
Summary:The English Channel cuttlefish (Sepia officinalis) is the most abundant cephalopod resource in the Northeast Atlantic and one of the three most valuable resources for English Channel fishers. Depletion methods and age-structured models have been used to assess the stock, though they have shown limitations related to the model assumptions and data demand. A two-stage biomass model is, therefore, proposed here using, as input data, four abundance indices derived from survey and commercial trawl data collected by Ifremer and Cefas. The model suggests great interannual variability in abundance during the 17 years of the period considered and a decreasing trend in recent years. Model results suggest that recruitment strength is independent of spawning-stock biomass, but appears to be influenced by environmental conditions such as sea surface temperature at the start of the life cycle. Trends in exploitation rate do not reveal evidence of overexploitation. Reference points are proposed and suggestions for management of the sustainable utilization of cuttlefish in the English Channel are advanced.