JPR Advance Access published online on June 17, 2008
Journal of Plankton Research, doi:10.1093/plankt/fbn066
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Modelling sardine and anchovy ichthyoplankton transport in the Canary Current System
1 Institut de Recherche pour le Développement, UR097 ECO-UP, CRHMT Centre de Recherche Halieutique Méditerranéenne et Tropicale. Avenue Jean Monnet, BP 171 34203 Sète Cedex, France 2 Institut National de Recherche Halieutique, 2 rue Tiznit Casablanca, Morocco 3 Institut de Recherche pour le Développement, UR079 Geodes, Institut des Systèmes Complexes, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon Cedex 07, France 4 Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Canary Islands, 35017 Las Palmas de Gran Canaria, Spain
CORRESPONDING AUTHOR: Timothée Brochier timbrochier{at}gmail.com
Received on March 20, 2008; revised on June 11, 2008; accepted on June 13, 2008
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Abstract |
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The Canary Current System, centred along the north-western coast of Africa, is one of the four major eastern boundary currents of the world ocean. It sustains a large amount of small pelagic fish, mainly sardine (Sardina pilchardus; Sardinella spp) and anchovy (Engraulis encrasicolus). One of the particularities of this system is the presence of the Canary archipelago, which is close enough to the continental coast to allow exchange of biological material between the two areas. We used intermediate-resolution (7 km) hydrodynamic simulations as inputs for an individual-based model to assess the transport of ichthyoplankton (1) along the African coast and (2) from the African coast to the Canary archipelago. We explored different scenarios of passive vs. active vertically swimming larvae to assess the possible impact of vertical migration on transport and retention. Transport along the coast was essentially southward. The zone located between Cape Drâa (
28°45’N) and Cape Juby (27°56 N) had relatively high levels of retention in autumn and winter. The zone extending from Cape Boujdor (26°12’N) up to Cape Blanc (21°N) had high retention levels during the entire year. Larvae transported from the coast to the archipelago came mainly from the area located between Cape Ghir (30°38’N) and Cape Juby, while larvae retained in the eddy field downstream of the islands originated mainly from the area between Cape Juby to Dakhla (24°N). The results are discussed in relation to available field data of anchovy and sardine egg distributions over the continental shelf, and compared with oceanic surveys of larval presence near the Canary archipelago.
Key Words: Upwelling • pelagic fish • ichthyoplankton • individual-based model • Lagrangian model • biophysical model • mesoscale
Communicating Editor: Professor Mark Gibbons