To efficiently manage and maintain fish stock abundance and age structure, it is necessary to understand variability in its spatial distribution. The main objective of this study was to describe the demographic structure of the Bay of Biscay anchovy during the main spawning period based on adult samples from 15 daily egg production method surveys. The proportion of age-1 individuals was modelled using generalized additive models with a binomial distribution and a logit link in relation to geographical and environmental covariates. The possibility of obtaining different models depending on the average age-1 proportion (low or high) was also explored. In general, age-1 individuals were found in shallow waters close to the coast, especially associated with the Gironde and Adour river plumes, whereas older individuals were prevalent on the shelf break and in oceanic waters. However, in years with a high age-1 proportion the younger individuals were also dominant in oceanic waters. These results could be used for management purposes, such as defining protected areas for particular age groups.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: Thanks are due to IFREMER, and especially to Jacques Masse, for providing the adult samples from the PELGAS acoustic survey. We also thank Inaki Rico for his work in otolith readings. Two anonymous referees provided valuable comments that helped to improve the manuscript. This study was funded by the Department of Agriculture and Fisheries of the Basque Country Government, the projects ECOANCHOA, REPRODUCE and the EU Project UNCOVER (Contract No. 022717). The work of Urtzi Laconcha was part of his MSc thesis at the University of Cadiz. This paper is contribution number 646 from AZTI-Tecnalia (Marine Research Division).
ASJC Scopus subject areas
- Aquatic Science