FOUNDATION > Great White Shark > Reproduction

Reproduction

White sharks are long lived and are low in abundance. Females do not become sexually mature until they reach a size of 4.5-5m whilst males mature at about 3.6m or over. Females have between 2 and 14 pups in each litter with the average being between 5 and 7 although mortality rates of neonates can be relatively high in the first year.

There are three modes of reproduction in elasmobranchs. In oviparity, the egg capsule develops in the uterus, which is specialised for the synthesis and secretion of materials, including the provision of oxygen and the elimination of water and waste products. In aplacental viviparity, the uterus functions as a respiratory membrane and an ionic regulator but does not provide nutrients to the developing embryo. This mode includes those species that exhibit oophagy and intra-uterine cannibalism. Finally, placental viviparity involves the uterus supplying nutrients to the embryo after yolk stores have been depleted.

The reproductive mode in white sharks is aplacental, or lecithotrophic, viviparity with the embryos being nourished by oophagy. There is no evidence of placental attachment in the embryos studied, but late-stage embryos are seen to have small well-healed scars on the throat which could represent the site of absorption of the yolk sac (Francis, 1996). The reproduction of white sharks was weakly understood in previous years but, since 1991, several pregnant females have been captured and examined giving us a greater insight into the reproductive strategy of this species (Francis, 1996).

It is estimated from recent studies that male white sharks mature when they reach approximately 360cm in length (Pratt, 1996).  However, this is a minimum estimation with some sharks still being classified as immature at much greater lengths, depending on the length and stage of calcification of the claspers. Females mature at between 450-500cm total length (Francis, 1996) but again can be immature at larger sizes up to 472cm (Springer, 1939). Based on the growth curve for north-east Pacific white sharks, ages at maturity are tentatively estimated to be 89 years for males and 1215 years for females (Cailliet et al., 1985).

Although commonly between 2 and 7, litter sizes in white sharks can be as large as 14. The largest embryo examined to date was 151cm long whilst the smallest free-swimming white shark recorded was 122cm (Casey and Pratt 1985, Klimley 1985). From these findings, the length at birth of a white shark is estimated to be in the 120-150cm range and 12-32kg, although this range is extended at both ends (Uchida et al, 1996).