HR: 1400h
AN: OS53A-03    [Abstracts]
TI: Larval Fish Assemblages, Environment and Circulation in a Semienclosed Sea (Gulf Of California).
AU: * Peguero, M
EM: tigermartha@yahoo.com
AF: ICMyL UNAM, Ciudad Universitaria, México, DF 04510, Mexico
AU: Sánchez-Velasco, L
EM: lsvelasc@ipn.mx
AF: CICIMAR, Ave. Instituto Politecnico Nacional, La Paz, BCS 23000, Mexico
AU: Lavín, M
EM: mlavin@cicese.mx
AF: CICESE, km 107 Carretera Tijuan-Ensenada, Ensenada, BC 22860, Mexico
AU: Marinone, G
EM: marinone@cicese.mx
AF: CICESE, km 107 Carretera Tijuan-Ensenada, Ensenada, BC 22860, Mexico
AB: Fish larvae and hydrographic data collected in the Gulf of California in December 2002 are used to describe the larval fish assemblages and to explore their relationships with environmental variables. The Bray-Curtis dissimilarity index defined three larval fish assemblages, whose goeographical distribution coincided with three areas defined by Principal Component Analysis of the environmental variables. The affinity of most of the species with the environmental characteristics of their areas of distribution could be interpreted as an indication that spawning occurred inside those areas. However, it is not known when the spawning took place, and the fast currents in the Gulf could rapidly disperse eggs and larvae. Since transport and retention is best studied from a Lagrangian point of view, the currents from a 3D numerical model were used to track large numbers of particles released in the different larval fish assemblage areas. Particle-tracking and connectivity matrices can help in assessing larval fish retention in seas that, like the Gulf of California, have well defined circulation patterns. On time scales around 30 days, retention occurred for the North assemblage in the Upper Gulf, for the Channel- Central assemblage in the anticyclone over the Norhern Gulf and in Ballenas Channel, and for the South assemblage in the eddy over San Pedro Mártir basin and in the shallow zone off the peninsula. Therefore, the Lagrangian analysis revealed that the observed larval fish assemblages have a permanency long enough to allow the larve to remain in a favorable environment until they develop motility.
DE: 4512 Currents
DE: 4890 Zooplankton
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly