Geographic variability of sardine growth across the northeastern Atlantic and the Mediterranean Sea

Type Article
Date 2008-04
Language English
Author(s) Silva A1, Carrera P2, Masse Jacques3, Uriarte A4, Santos M5, Oliveira P1, Soares E1, Porteiro C5, Stratoudakis Y1
Affiliation(s) 1 : Inst Invest Pescas & Mar INIAP IPIMAR, P-1449006 Lisbon, Portugal.
2 : Museo Mar Galicia, Vigo 36280, Spain.
3 : IFREMER, F-44311 Nantes, France.
4 : AZTI, Pasaia 20110, Gipuzkoa, Spain.
5 : Ctr Oceanograf Vigo, IEO, Vigo 36280, Spain.
Source Fisheries Research (0165-7836) (Elsevier), 2008-04 , Vol. 90 , N. 1-3 , P. 56-69
DOI 10.1016/j.fishres.2007.09.011
WOS© Times Cited 25
Keyword(s) Iberian Biscay region, Spatio temporal variation, Growth, Sardina pilchardus
Abstract This study describes broad-scale spatial variations in sardine growth across the northeastern Atlantic and Mediterranean waters using opportunistic samples collected in recent years. More detailed information on spatial, decadal and seasonal growth variations is provided for the Iberian-Biscay region using data collected in acoustic surveys since the mid-1980s. Growth curves are fitted to annual or monthly length-at-age data using a robust Von Bertalanffy model; parameters for recent samples are compared with literature information using an auximetric plot while differences between areas within the Iberian-Biscay region are tested by log-likelihood ratio tests. Sardine growth performance is generally lower in the Mediterranean and declines across the northeastern Atlantic from the English Channel to north Morocco but increases sharply off Mauritania. Lower growth of Mediterranean sardines is possibly associated to the overall oligotrophy of this Sea while differentiation from the Atlantic is likely sustained by reproductive isolation between populations from the two areas. Within the northeastern Atlantic, size- and age related migrations may partly explain differences in maximum length/age and mean length-at-age between neighbouring areas but the broad-scale latitudinal decline in growth is consistent with adaptation to the north-south decline in seasonal temperature gradients and to the annual cycles of plankton production. Within the Atlantic Iberian waters, sardine grows and improves in condition during spring and summer when the allocation of energetic resources for gonad development cease, temperature is close to the annual maxima and plankton production is high. Variation in sardine length-at-age and growth within the Atianto-lberian stock area has implications for stock structure and needs to be taken into account in the calculation of weight and maturity-at-age for assessment purposes. No evidence of broad temporal changes in sardine growth within the Iberian-Biscay region is obtained. (C) 2007 Elsevier B.V. All rights reserved.
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