Data/hora: 11/06/2024 12:23:44

Provedor de dados: | Institutional Archive of Ifreme (ArchiMer)
País: | France
Título: | Déclin de la taille-aux-âges des sardines (Sardina pilchardus) : diminution de la croissance et/ou disparition sélective des individus à croissance rapide
Autores: | Gentil, Claire.
Data: | 2018
Ano: | 2018
Palavras-chave: | Sardina pilchardus; Golfe de Gascogne; Otolithes; Croissance; Mortalité; Sélection; Sardina pilchardus; Bay of Biscay; Otoliths; Growth; Mortality; Selection.
Resumo: | In many exploited species, we see a decrease of size-at-ages. Two main hypotheses have been proposed to explain this decline: a decline in growth and the selective mortality of the individuals with fast growth both being due to environmental changes or/and to fishing. The sardine Sardina pilchardus of the Bay of Biscay is a good model for the study of this phenomenon because of its high sensitivity to the environmental variations and it sustains two large French and Spanish fisheries. The aim of this study is to measure the changes in the growth of sardines, by the reading of otoliths, and to understand mechanisms involved in this process. The main stages of this study are described in this report: extraction of otoliths during PELGAS, otoliths measurements on a subset of individuals, data analyses in R, and comparing with environmental data (estimated biomass by acoustic, biomass captured, and temperature). We have noted that the decline of growth was only in certain periods and that the strength and direction of the selective mortality is dependent on cohorts. It is therefore likely that the decline in size-at-ages in this species is mainly due to changes in growth at age 1 but we found no significant relationship between growth (and mortality) with the studied environmental parameters. As this study was conducted with a relatively small data set and large scale environmental data, further analyses are required to fully address this issue.
Tipo: | Text
Idioma: | Francês

Identificador:

http://archimer.ifremer.fr/doc/00459/57038/58942.pdf

http://archimer.ifremer.fr/doc/00459/57038/

Formato: | application/pdf

Fonte:

2018 Ifremer, CNAM Intechmer

info:eu-repo/semantics/openAccess

restricted use