Modelling sardine and anchovy ichthyoplankton transport in the Canary Current System
Authored by Christophe Lett, Timothee Brochier, Eric Machu, Pierre Freon, Azeddine Ramzi, Amina Berraho, Santiago Hernandez-Leon
Date Published: 2008
DOI: 10.1093/plankt/fbn066
Sponsors:
European Union
Platforms:
No platforms listed
Model Documentation:
Other Narrative
Model Code URLs:
Model code not found
Abstract
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
(i) along the African coast and (ii) from the African coast to the
Canary archipelago. We explored different scenarios of passive versus
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 Draa (similar
to 28 degrees 45'N) and Cape Juby (similar to 27 degrees 56 N) had
relatively high levels of retention in autumn and winter. The zone
extending from Cape Boujdor (similar to 26 degrees 12'N) up to Cape
Blanc (similar to 21 degrees 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 (similar to 30 degrees
38'N) and Cape Juby, whereas larvae retained in the eddy field
downstream of the islands originated mainly from the area between Cape
Juby to Dakhla (similar to 24 degrees 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.
Tags
Vertical-distribution
Southern
benguela
Upwelling ecosystem
Retention processes
Pilchardus larvae
Engraulis-encrasicolus
Northwest africa
Physical-biological interactions
Coastal transition zone
Northern benguela