Density dependence in the spatial behaviour of anchovy and sardine across Mediterranean systems

Type Poster
Date 2012
Language English
Author(s) Giannoulaki Marianna1, Petitgas Pierre2, Barra Marco3, Tugores Pilar4, Vasapollo C.5, Iglesias M.4, Leonori Iole5, de Felice Andrea5, Bonanno A.3, Basilone G.3, Mazzola Salvatore3, Bigot Jean-Louis6, Machias Athanassios1, Pyrounaki Maria M.1
Affiliation(s) 1 : Hellenic Centre for Marine Research, Institute of Marine Biological Resources and Inland Waters, PO Box 2214, GR 71003, Iraklion, Greece
2 : Institut Français de Recherche pour l'Exploitation de la Mer, BP 21105, F- 44311 cedex 03, Nantes, France
3 : Istituto per l'Ambiente Marino Costiero, Consiglio Nazionale delle Ricerche, Capo Granitola, 91021, Campobello di Mazara (TP), Italy
4 : Instituto Español de Oceanografia, Centro Oceanográfico de Baleares, Muelle de Poniente s/n, 07015 Palma de Mallorca, Baleares, España
5 : Istituto di Scienze Marine, CNR, Largo Fiera della Pesca, 60125 Ancona, Italy
6 : IFREMER, Boulevard Jean Monnet, B.P. 171 34203, Sète Cedex, France
Meeting ICES Annual Science Conference
Note ICES CM 2012/B:19
Keyword(s) anchovy, Mediterranean Sea, sardine, spreading area index
Abstract A spatial indicator—the spreading area index—is used to describe anchovy and sardine spatial distribution in relation to biomass variation and to look for ecosystem differences within the Mediterranean basin. Specifically, the variation in the spreading area index in relation to biomass was examined for different areas of the Mediterranean Sea (i.e. Aegean Sea, western Adriatic Sea, Strait of Sicily, Gulf of Lion, and Spanish Mediterranean waters). In order to
capture the spatial variability of the population at different levels of fish density, acoustic survey data for the years of highest, lowest, and intermediate abundance were used. In a subsequent step standardized values of spreading area and biomass were estimated to allow comparisons.
Results showed pronounced area differences. A significant relationship was revealed in the case of anchovy for areas with extended continental shelf (i.e. Aegean Sea, Adriatic Sea, and Gulf of Lion), indicating an increase in biomass with an increase in the spreading area. No relationship was found for areas dominated by narrow continental shelf and strong currents (i.e. Spanish Mediterranean waters and the Strait of Sicily). With regard to sardine, an increase in biomass was followed by an increase in the spreading area when estimates from the Aegean Sea, the Adriatic Sea, and the Strait of Sicily were considered together. The relationship was even more Abstracts–Theme Session B 9 pronounced when analysis was limited to the Aegean Sea and the Strait of Sicily. No relationship was found for the Spanish Mediterranean waters and the Gulf of Lion. This clearly implies that spatial indicators should be integrated into ecosystem management, taking into account that they can be area‐ or ecosystem‐dependent.
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Giannoulaki Marianna, Petitgas Pierre, Barra Marco, Tugores Pilar, Vasapollo C., Iglesias M., Leonori Iole, de Felice Andrea, Bonanno A., Basilone G., Mazzola Salvatore, Bigot Jean-Louis, Machias Athanassios, Pyrounaki Maria M. (2012). Density dependence in the spatial behaviour of anchovy and sardine across Mediterranean systems. ICES Annual Science Conference.