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African Journal of Marine Science

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A preliminary study of age and growth of the smoothhound shark mustelus mustelus (triakidae)

AJJ Goosen, MJ Smale

Abstract


Age and growth of the smoothhound shark Mustelus mustelus was investigated from banding patterns in sectioned vertebral centra of 136 specimens, using a modified Alizarin red S technique to stain bands on the
centra. Fabensf method (Lt = L‡ . (L‡ . L0)e.Kt) was statistically more robust than the Von Bertalanffy method, and provided growth models of Lt = 2 041.8 . (2 041.8 . 390)e.0.06t for females and Lt = 1 530.1 .(1 530.1 . 390)e.0.1t for males. The Von Bertalanffy growth model was, however, used because of insignificant differences between the two methods. Parameters obtained were: Lt = 2 049.6 (1.e.0.06(t+3.55)) for females and Lt = 1 451 (1e.0.12(t+2.14)) for males. The predicted age at maturity was 6 .9 years for males and 12 .15 years for females. The oldest female in the samplewas estimated to be 24 years and measured 1 640 mm total length (TL); the oldest male was estimated to be 17 years and measured 1 280 mm TL. Results are considered preliminary, because the assumptions with regard to timing of bands formation could not be validated.



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