|Published in||Pan-American Journal of Aquatic Sciencesv. 9(3):154|
Torquato, F.O. and Muelbert, J.H.
This study aimed to understand the role of physical and biological features on the vertical distribution of Engraulis anchoita larvae. Samples were obtained during winter 2005 and summer 2007 off Albardão (33°S) during day and night with a Multinet equipped with two 200 &mum and three 330 &mum mesh-nets. Vertical profiles of salinity, temperature and larval abundance were made to evaluate spatial distribution patterns. Temperature-Salinity-Icthyoplankton (TSI) diagrams were used to infer anchovy
larvae distribution with respect to water mass composition. Diel variation in the vertical distribution was analyzed by estimating the depth of the center of mass (ZMC). Results showed seasonal differences in the number of anchovy larvae with much more larvae recorded during winter than in summer. In winter, anchovy larvae were located mainly in cold, low salinity and non-stratified waters from Río de la Plata Plume Water. Diel vertical movements indicated reverse and small scale migration through the water
column. During summer, all larvae were recorded above twenty-three meters depth and in stations which presented warm water. There was also evidence that larvae performed small and reverse vertical movements. Our data suggest that the seasonal abundance and distribution of larvae of E. anchoita seem to be synergistically influenced by adult reproductive behavior and environmental factors.