Early anchovy stages abundance variability and larval condition at the fixed coastal station EPEA between 2000-2017

LEONARDUZZI, EZEQUIEL; DO SOUTO, MARINA; DIAZ MARINA VERA

Marine and Fishery Sciences

INIDEP

Lugar: Mar del Plata; Año: 2021 vol. 34 p. 123 - 142

2683-7595

Densities of Engraulis anchoita eggs and larvae and larval nutritional condition were analyzed at the fixed sampling station (EPEA) within the period 2000-2017. These variables were analyzed seasonally, and the trends over time were determined. Ichthyoplankton samples were collected by oblique trawls using Bongo nets with 300 μm of pore mesh and fixed with formaldehyde 5% in seawater. Eggs and larvae densities were determined, and six morphometric variables were measured to estimate larval nutritional condition. The developmental stage of each specimen was also determined. The highest mean value of egg density was detected in the October-December period, with a secondary mode in August, followed by one in March. Larval density presented a mode in October. Autumn and spring were the most favorable seasons for larval condition while winter proved to be the least favorable one. An increase in food availability during autumn and spring due to primary and secondary production peaks could explain the high nutritional condition and growth values observed in these seasons at the EPEA. No changes were detected in the trends over time of the studied variables. The integrated study of density and nutritional condition of E. anchoita larvae allows the determination of favorable breeding periods for the species while the continuation of the long term study will allow evaluating the possible climate change effects on the first life stages of this species.