### Demography of the White Shark Carcharodon carcharias (Linnaeus, 1758) Based on age-at-first-reproduction of 15 years,longevity 60 years, natural mortality =-ln (0.01)/60 = 0.07675 yr-1, and mean litter size of 8.9 every third year.

 Age-at-first-reproduction 15 years assuming TL-at-maturity of ~5 m (Cailliet et al. 1983, Mollet et al. 2000), agrees with results of vertebrae of Morro Bay white shark (TL = 4.3 m) which had ~12 bands and was probably about 2-3 years from being mature. Longevity ~60 years (Cailliet et al. 1983 VBGF with lohgevity estimate based upon 5 ln2/k), Mortality, assume M = -ln(0.01)/60 = 0.07675 yr-1, (S = 0.9261) based on longevity of 60 years. Fecundity, used mean litter size of mean of 8.9 (Francis 1996) every third year (Mollet et al. 2000), i.e. effective annual female fecundity of 8.9/(2x3) = 1.4833. Mollet et al. (2000) presented evidence that the gestation time of the white shark is 18 months but forgot to suggest that the reproductive cycle is accordingly most likely 3 years long. Uchida et al. (1996) reported a litter of 10 with a total estimated mass of 263 kg (17.2% of1528 kg mass of female). ( A model using pregnant and resting stages in combination with actual female fecundity would be better and produce a higher lambda, but here I wanted to present the smallest matrix possible. The difference is substantial for a species with a low age-at-maturity). Solution using life history table or 55x55 Leslie matrix: Lambda = 1.0082, growth rate of stable population (r = ln (lambda) = 0.0816 yr-1); Net reproductvie rate Ro = 6.163, Generation "times": Abar = 20.91 yr (an age), T = ln(Ro)/r = 23.11 yr, mu1 = 26.15 yr (an age) Abar/alpha = 1.394 Elasticities from life history table or 55x55 Leslie matrix (assuming gestation period (GP) of 1.5 yr) E(fertility) = E(m) = E1 = 1/Abar = 0.0478; E(juvenile survival) = E(JS) = E2 =alpha * E1 = 0.7174 (ratio ER2 = alpha = 15.0); E(adult survival) = E(AS) = E3 = 1 - E2 = 0.2826 (ratio ER3 = Abar - alpha = 5.91); (E1 + E2 + E3 = 1.0478; could normalize to 1.0 if needed; ER2 + ER3 = Abar = 20.9); Normalized Elasticities: E1 = 4.56%, E2 = 68.5%, E3 = 27.0%, E3/E2 = 0.394

Created April 2001, revised April 2001. Back to previous page.