Study on the nutritional condition of Argentine anchovy (Engraulis anchoita) Northern stock larvae in relation to the hydrographic features of the nursery area

Abstract

The study of larvae nutritional condition allows to assess the physiologic state that reflects the environmental situation they were exposed to. It represents a useful instrument to determine favourable nursery areas, provides tools for the management of a population subject to fishing and furnishes information to establish appropriate closed areas and periods. The material analyzed derived from three cruises carried out to assess Argentine anchovy Northern stock during the 2003, 2004 and 2006 reproductive peak. The objective of this work was to study the nutritional status of Argentine anchovy first feeding larvae caught in the coastal and mid-shelf of the Río de la Plata River maritime front in relation to the hydrographic features of the nursery area. The condition of Argentine anchovy larvae caught in areas with different oceanographic characteristics (estuarine zone, mix or frontal and shelf waters) was compared. To determine the nutritional status the Principal Component Analysis employing five morphometric variables and weight, the Fulton Condition Factor and length-weight relation of specimens was performed. The results obtained in the three reproductive seasons analyzed show that the nutritional condition was better in areas with mix characteristics as compared to areas influenced by estuarine and shelf waters. The use of morphometric variables and weight allows to find differences in the growth rate and nutritional condition of Argentine anchovy larvae obtained in areas characterized by different oceanographic scenarios.