Reproductive biology of the whiskery shark, Furgaleus macki, off south-western Australia

Abstract

The whiskery shark, Furgaleus macki, is important in the commercial shark fishery off southern Western Australia. The reproductive biology was studied with the aid of 88 specimens collected by commercial gill-net vessels off south-western Australia between March 1994 and August 1996. The size selectivity of the gill-nets resulted in only mature and large juvenile specimens being caught. Size at birth was estimated to be 22–27 cm total length. Size (fork length) at maturity was 107 cm for males and 112 cm for females. There is a seasonal reproductive cycle. Mating is most likely to occur from August to September, with females storing spermatozoa until ovulation in late January to early April. Gestation lasts 7–9 months, with parturition from August to October. Litter sizes vary from 4 to 28 (mean 19). There was a significant linear relationship between litter size and maternal length. Mature males mate each year, but females produce litters every second year. Mature non-pregnant females develop large yolky ova from March to October, with development of the ova completed several months before ovulation. The results are compared with previous records and with data for other species of the family Triakidae that occur off southern Australia.