Journal Article

Temporal and geographic variability of sardine maturity at length in the northeastern Atlantic and the western Mediterranean

A. Silva, M.B. Santos, B. Caneco, G. Pestana, C. Porteiro, P. Carrera and Y. Stratoudakis

in ICES Journal of Marine Science

Published on behalf of ICES/CIEM

Volume 63, issue 4, pages 663-676
Published in print January 2006 | ISSN: 1054-3139
Published online January 2006 | e-ISSN: 1095-9289 | DOI: http://dx.doi.org/10.1016/j.icesjms.2006.01.005
Temporal and geographic variability of sardine maturity at length in the northeastern Atlantic and the western Mediterranean

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We investigate spatial and temporal variations in sardine maturation patterns and discuss the implications for stock structure, using recent samples collected opportunistically across the species range and data collected regularly for the assessment of the Atlanto-Iberian stock. Maturity ogives were fitted to maturity-at-length data using Generalized Linear Models, and maturation patterns are summarized by length at first maturity (L50). Sardine attain sexual maturity at a total length of 10.9–16.8 cm. The percentage of mature small sardine increases from north to south across the Northeast Atlantic. L50 is low in the Mediterranean and Moroccan waters, but maturation is delayed towards the limits of the species' range. Sardine mature smaller in the Gulf of Cadiz than in other areas of the Atlanto-Iberian stock, although there is no indication of a different maturation pattern north of the stock boundary. These results are not sufficient to review the stock structure of sardine, but question the hypothesis of homogeneous biological properties of sardine populations within the stock area. Sardine maturation length reduced and the spawning period extended in western Iberia during the past two decades. Associated increases in fish condition and fat reserves during the summer feeding season suggest that variations in reproductive traits may have been caused by environmentally driven changes in food availability.

Keywords: condition; Iberian waters; maturity at length; sardine; stock structure

Journal Article.  8222 words.  Illustrated.

Subjects: Environmental Science ; Marine and Estuarine Biology

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