| Popis: |
Aspects of the life history and biology of two sympatric coastal shark species (Mustelus mustelus and M. palumbes) off southern Africa are described and compared. Free-swimming male M. mustelus measured 390–1 450 mm total length (TL), whereas females were recorded up to 1 650 mm TL. Most specimens of both sexes were found at depths shallower than 100 m. Males mature at 950–1 300 mm TL and females at 1 250–1 400 mm TL. Reproduction is seasonal, and each cycle may take one year or longer, if there is a resting period between pregnancies. Litter size was correlated with female size and varied between 2 and 23. The largest embryo measured 425 mm TL. The hepatosomatic indices were negatively correlated to embryo length in both species. Prey was dominated by crustaceans, although cephalopods became important in larger M. mustelus. There was a good relationship between prey size and fish size. Free swimming male M. palumbes measured 275–1 008 mm TL, whereas females were recorded up to 1 126 mm TL. M. palumbes ma... |
