Thesis
DISTRIBUCIÓN ESPACIO-TEMPORAL DE LAS ASOCIACIONES DE LARVAS DE PECES EN EL NORTE DEL GOLFO DE CALIFORNIA
Autor
BIOL. PEIRO ALCANTAR, MARÍA TERESA
Institución
Resumen
ABSTRACT
Environmental requirements that promote the fish reproductive success are a
combination of factors, both physical and biological processes that influence different
spatial and temporal scales. For this reason, four exploratory fishing cruises were
carried out along the northern Gulf of California between 2005 and 2007; vertical
plankton tows were made with Bongo net and hydrocast with CTD, at maximum of
200 m depth. The abundance and distribution information of fish larvae was analyzed
in order to identify the spatio-temporal variation in relation to environmental
characteristics. A total of 93 species was identified, belonging to 41 families and 61
genera. Engraulis mordax, had the highest relative abundance (> 80%) in March,
2005 and April, 2007 and Benthosema panamense in July, 2005 and November,
2006 (40 and 52%). Canonical Correspondence Analysis (CCA) allowed the
differentiation of two periods: the cold period (March-April) and the warm period (July-
November). In the cold period, there were two water masses: Gulf of California Water
(GCW) that was predominant in the sample of April 2007 and Subtropical Subsurface
Water (SsStW). In April, the species diversity was low (0.9 bits/ind.), but increased
twice in March (2.1 bits/ind.). During the cold period, E. mordax was the dominant
species, associated with temperate and subtropical affinity species (Merluccius
productus and Citharichthys fragilis). During the warm period, the GCW was
predominant in July, 2005 and three water masses were present in November, 2006
(AGCW SsStW and Equatorial Surface Water). In the warm period, diversity was
higher in July (2.5 bits/ind.), but decreased slightly in November (1.9 bits/ind.). The
assemblages during the warm period presented characteristics of tropical and
subtropical affinity species, such as mesopelagic B. panamense and Vinciguerria
lucetia. Dominant species were found in each of the of larval fish assemblages, these
species and hydrographic characteristics show a clear seasonality in the area.