A re-examination of the age and growth of sand tiger sharks, Carcharias taurus, in the western North Atlantic: the importance of ageing protocols and use of multiple back-calculation techniques |
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Authors: | Kenneth J Goldman Steven Branstetter John A Musick |
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Institution: | (1) Alaska Department of Fish and Game, 3298 Douglas Pl., Homer, AK 99603, USA;(2) National Marine Fisheries Service, 9721 Executive Center Drive North, Koger Building, Suite 201, St Petersburg, FL 33712, USA;(3) College of William and Mary, Virginia Institute of Marine Science, School of Marine Science, Route 1208, Greate Road, Gloucester Point, VA 23062, USA |
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Abstract: | Age and growth estimates for sand tiger sharks, Carcharias taurus, in the western North Atlantic were derived from 96 vertebral centra collected from sharks ranging from 94 to 277 cm total length (TL), and compared to previously published age and growth data. The oldest female and male sand tiger sharks aged in this study were 17 and 15 years of age, respectively. von Bertalanffy growth parameters derived from vertebral length-at-age data are L
∞ = 295.8 cm TL, k = 0.11 year−1, and t
0 = −4.2 years for females, and L
∞ = 249.5 cm TL, k = 0.16 year−1, and t
0 = −3.4 years for males. Sexual maturity is estimated to be 9–10 years for females and 6–7 years for males. Weight-to-length relationships determined for female and male sand tiger sharks in the western North Atlantic are; W = 1.3 × 10−4 × L
2.4 (r
2
= 0.84, n = 55) and W = 9.0 × 10−5 × L
2.5 (r
2
= 0.84, n = 47), respectively, and 7.9 × 10−5 × L
2.5 (r
2
= 0.84) for the sexes combined. Our results show sand tigers possess a slower rate of growth than previously thought. This information is crucial for accurately assessing this population’s ability to recover, and further justifies the need for this species to be fully protected. |
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Keywords: | Elasmobranch Life history Growth rate Back-calculation Reproduction |
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