Reproductive biology of shortnose spiny dogfish, Squalus megalops, from the Agulhas Bank, South Africa

Abstract

Aspects of the reproductive biology of Squalus megalops were investigated in material collected from commercial and research trawl samples from the Agulhas Bank. The largest male measured 572 mm TL and the largest female 782 mm. The size at which 50% of the males in the population were sexually mature was ~400 mm; 50% of the females were mature at ~500 mm, and 50% were pregnant at ~510 mm. Litter size varied from 2 to 4 but only the largest females had the maximum litter size. Reproduction in S. megalops is aplacental-viviparous, and the pups are 232–277 mm at birth. The sex ratio of embryos was not significantly different from unity. Trawled dogfish had a sex ratio significantly different from unity, probably because of sampling bias; aggregations were apparently not adequately sampled over their entire distribution.