Employment of morphometric variables to assess nutritional condition of Argentine anchovy larvae Engraulis anchoita Hubbs & Marini, 1935

Abstract

Most important causes of larval mortality are predation and starvation. The latter can be assessed by the measurement of the nutritional condition. The objective of the present study was to evaluate the nutritional condition of E. anchoita larvae employing morphometric techniques in three different hydrographic areas of the Argentine sea in order to establish regional and interpopulation variability: El Rincon coastal area, Outer-shelf and Pen nsula Valdes tidal front. Sampled larvae from El Rincon coastal area showed a higher growth rate (growth curve slope = 3.575) but had lower weight, and thus low Fulton (15.71 +/- 3.58, n = 41) and Le Cren (0.63 +/- 0.13, n = 41) condition indices, in comparison to specimens from the other two areas (P < 0.001). The Principal Component Analysis, employing morphometrical variables and weight, separated larvae from El Rincon from larvae captured in the other areas. These results could be explained as a consequence of an increase in density dependent mortality or food competition in El Rincon due to a year with an exceptional high larvae production. Our results showed that the use of morphometrical variables and weight allow to find differences in growth rate and nutritional condition among anchovy larvae collected in areas characterized by dissimilar oceanographic scenarios.