Muestreo bioestadístico de pescado en el puerto de Mar del Plata. Corvina rubia (Micropogonias furnieri). Período 1986-1988.

Abstract

The present work analyzes the samples of white croaker (Micropogonias furnieri) from commercial landings, carried out in the sea port of Mar del Plata (Buenos Aires province, Argentina) during the 1986-1988 period. A total of 120 samples were taken, recording individual total length in cm (TL), to obtain the length distribution of catches. Nineteen of these samples were subsampled. During the three years analyzed the length range of commercial landings ranged between 21-78 cm TL, while the more frequent length interval was 30-50 cm TL, with modes between 36-40 cm TL. The length/weight relationship by year is given by the following equations: 1) 1986 W=0.017x L super(2.88); 2) 1987 W=0.020x L super(2.84); 3) 1988 W=0.020x L super(2.85). Most individuals were in gonadal rest during almost the whole year, with low presence of 3 and 6/3 stages, which appear in spring-summer. The first maturity length was calculated through the use of a logistic model. The length in which 50 percent of the individuals are mature corresponds to 33.66 cm Tl and to an age of 3-4 years. The most abundant ages in the commercial catches were between 2-27 years, even through ages until 39 years were determined. The growth parameters were fitted to von Bertalanffy growth function through the program LFSA (Length Based Fish Stock Assessment) implemented by FAO. The growth equation corresponding to 1986 showed the best fit, which is: L infinity (cm)=45.76x (1-e super(-0.19x (t-(-3.41))). The absence of the ages 0-1 and the low presence of the classes 2-4 into the commercial catches, reduces precision in the estimate of growth parameters, especially during 1987 and 1988. For this reason these calculations will be fitted to data of research survey, where the discard does not exist.