DISTRIBUCIÓN ESPACIO-TEMPORAL DE LAS ASOCIACIONES DE LARVAS DE PECES EN EL NORTE DEL GOLFO DE CALIFORNIA

Abstract

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.