ICES Journal of Marine Science: Journal du Conseil Advance Access published online on January 19, 2009
ICES Journal of Marine Science: Journal du Conseil, doi:10.1093/icesjms/fsn225
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Geographic variability of sardine dynamics in the Iberian Biscay region
1 Instituto Nacional de Recursos Biologicos (INRB-IPIMAR), Avenida Brasília s/n, 1449 006 Lisboa, Portugal
2 Institute of Marine Research, PO Box 1870 Nordnes, N-5817 Bergen, Norway
3 AZTI-Tecnalia, Herrera Kaia, Portualdea z/g, 20110 Pasaia, Spain
4 IFREMER, Rue de l'Ile d'Yeu, B.P 21105, 44311 Nantes Cedex 3, France
5 Instituto Español de Oceanografía (IEO), Centro Oceanográfico de Vigo, Apdo. 1552, 36280 Vigo, Spain
6 Museo do Mar de Galicia, Avenida Atlántida 160, 36280 Vigo, Spain
Correspondence to A. Silva: tel: +351 213027000; fax: +351 213015948; e-mail: asilva{at}ipimar.pt.
Silva, A., Skagen, D. W., Uriarte, A., Massé, J., Santos, M. B., Marques, V., Carrera, P., Beillois, P., Pestana, G., Porteiro, C., and Stratoudakis, Y. 2009. Geographic variability of sardine dynamics in the Iberian Biscay region. – ICES Journal of Marine Science, 66: 000–000.The spatio-temporal variability in the distribution, demographic structure, recruitment, and mortality of sardine within the Iberian Biscay region is described using area-disaggregated data collected during acoustic surveys and at ports since the mid-1980s. Multiple regression models were used to describe log numbers-at-age obtained annually in ten areas covered by three surveys to test the existence of geographic differences in selectivity-at-age, recruitment strength, and mortality and to infer plausible migration routes. Within Iberian waters, sardine biomass was mainly concentrated off western Portugal and the Gulf of Cadiz. In the Bay of Biscay, biomass levels were comparable with those off western Portugal. Recruitment was localized in a few areas (northern Portugal and the Gulf of Cadiz and Bay of Biscay), intermingling with areas dominated by older fish. Recruitment was generally asynchronous among areas, although some recruitment peaks were noticeable across wider regions. Spatial patterns related to strong and weak year classes and year-class slopes were also noted. Clearly distinct dynamics were not evidenced within the Atlanto–Iberian sardine stock area, but the validity of the northern limit was questioned by the connection between sardine dynamics in the Bay of Biscay and the Cantabrian Sea. The results provided some evidence consistent with the hypothesis of sardine movement from recruiting grounds to areas farther along the coast as they grow.
Keywords: Iberian Peninsula, population dynamics, small pelagic fish, stock structure
Received 22 July 2008; accepted 20 December 2008.