Vertical Distribution of Fish Larvae and Its Relation to Water Column Structure in the Southwestern Gulf of California¹

Abstract

The seasonal evolution of vertical distribution of fish larvae and its relationship with seasonal stratification, as measured by a quantitative stability parameter, were analyzed for a region off Bahía de La Paz in the southwestern Gulf of California. Samples were obtained with an opening-closing net (505 mm) in 50-m depth strata from surface to 200-m depth in May, July, and October 2001 and February 2002. Significant differences in total larval abundance and in dominant species (mesopelagic and epipelagic) were found among strata from May to October. More larvae were found in maximum-stability strata (from 16 G 5 to 48 G 17 m depth) than below the pycnocline (from 100-to 150-m depth). In February, the 100-m-deep surface mixed layer had a weak pycnocline at its base, and no significant difference was found. Results show that vertical distribution of fish larvae in this area depends mainly on the seasonal evolution of the water column structure, with most fish larvae in the pycnocline, at the most stable stratum of the water column.

Larval fish habitats in a mesoscale dipole eddy in the gulf of California

“…This stratified technique has been used successfully in previous studies (e.g. Espinosa-Fuentes and Flores-Coto, 2004;Sánchez-Velasco et al, 2007).…”

Role of circulation scales and water mass distributions on larval fish habitats in the Eastern Tropical Pacific off Mexico

“…To obtain a representative mean of the physical variables in the water column in each sampling station, we chose the depth of the 24.5 kg m −3 isopycnal, as a good indicator of the thermocline depth. In studies of the vertical distribution of fish larvae it is observed that most of the larvae were found in and above the thermocline [ Loeb and Nichols , ; Sánchez‐Velasco et al ., ; Danell‐Jiménez et al ., ]. On the other hand, Kessler [] in his review of the circulation of the Eastern Tropical Pacific argues that this isopycnal of 24.5 kg m −3 is one that best represents the seasonal movements of the pycnocline.…”

Life-history characteristics of eleotrid fishes of the western hemisphere, and perils of life in a vanishing environment

“…It has also been taken in ichthyoplankton collections from the Gulf of California in water of depths of 200-2,000 m (Sánchez-Velasco et al 2007). While individuals of this species were found to be relatively abundant in Río Claro, Corcovado National Park, Costa Rica.…”