Larval and juvenile growth of two Patagonian small pelagic fishes: Engraulis anchoita and Sprattus fuegensis

Abstract

Patagonian anchovy (Engraulis anchoita) and sprat (Sprattus fuegensis) constitute the two most important pelagic resources of the Argentine Patagonian shelf. Age and growth parameters of larvae and juveniles of both species were determined analyzing otoliths daily increments. A total of 404 anchovies (4.1-33 mm SL) and 157 sprats (5-41 mm SL) were analyzed. The Laird-Gompertz growth model was fitted to the length-at-age data of anchovies: L(t) = 4.2 exp (2.28 (1-(-0.034 t))). The parameters of the model were: L¥: 41.06 mm; the inflection point: 15.11 mm and 27 days; and the maximum growth rate: 0.51 mm day^-1. The length-at-age data of sprat larvae and juveniles were represented in two linear models: L(t) = 0.32 t + 7.6; and L(t) = 0.22 t + 6.6. Slopes represented mean growth rates, 0.32 and 0.22 mm day^-1 for larvae and juveniles, respectively. Variations in length-at-age between years were determined through the analysis of individual growth trajectories. Variations were found in sprats, not in anchovies.