Reproductive biology of Psammobatis extenta

Abstract

Psammobatis extenta collected from the commercial bottom trawl fishery operating in Puerto Quequén, Argentina, between 2000 and 2001, had a sex ratio of 1:1 (535 specimens). Both the largest male and female measured 313 mm total length (LT). The relationship between total body mass and LT was significantly different between sexes; mature females weighed more than mature males for a given LT. The size at which 50% of males were sexually mature was 262 mm LT (83·6% of the maximum size), whereas 50% of females were mature at 249 mm LT (80·0% of the maximum size). The gonadosomatic index in mature males and females was slightly higher during summer, but did not show significant variation over the sampling period. The hepatosomatic index of males and females was higher during the autumn and winter and followed a distinct seasonal pattern. Evidence suggested a continuous reproductive cycle during the year, with a maximum number of females carrying egg‐cases in summer.