Detecting the effects of inter-annual and seasonal changes in environmental factors on the striped red mullet population in the Bay of Biscay

Claire Kermorvant*, Nathalie Caill-Milly, Damien Sous, Iosu Paradinas, Muriel Lissardy, Benoit Liquet

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Climate fluctuations affect a wide range of environmental factors that may impact fish populations with various response mechanisms. For a major part of world fisheries stocks, only abundance time-series are available. Relations between abundance of these species and ocean variables, including long term trends and patterns of seasonal change, remain sparsely documented. The main aim of our work is to determine to what extent effects of inter-annual and seasonal changes in environmental factors can be identified and quantified on a selected time-series of abundance data-set: the striped red mullet population within the Bay of Biscay. 8 Landings per unit of effort (LPUE) for striped red mullet data are compared with environmental covariates extracted from the Copernicus web database. Our strategy is to decompose the patterns of change in fish populations into long-term and seasonal components and to analyse the possible dependency of both components on environmental factors. The overall tendencies are a decrease of the long-term component and a modification of the seasonality, with additional spatial variability. The observed tendencies and seasonal changes are discussed against the spatio-temporal patterns of change in environmental factors. High spatial heterogeneity within the Bay of Biscay was found, both for striped red mullet long-term trends and seasonal changes. Most inter-annual and seasonal changes in striped red mullet abundance can be related to environmental factors. In addition to the well-known annual fluctuation, most coastal sites revealed a bi-annual seasonality possibly related to the recruitment process.

Original languageEnglish
Article number102008
Pages (from-to)1-11
Number of pages11
JournalJournal of Sea Research
Volume169
DOIs
Publication statusPublished - Mar 2021

Keywords

  • Bay of Biscay
  • Climate change
  • Environmental modelling
  • Fisheries indicators
  • Mullus surmuletus
  • Time-series decomposition

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