Age and growth of the soldier, Sebastes capensis (Pisces: Scorpaenidae) at Tristan da Cunha and Gough Island, South Atlantic Ocean |
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Authors: | T G Andrew T Hecht |
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Institution: | Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown 6140, South Africa |
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Abstract: | Age and growth in the scorpaenid Sebastes capensis was studied at Tristan da Cunha and Gough Island using otoliths. The growth rate of specimens collected at Gough Island was almost twice that of specimens collected at Tristan da Cunha. The largest specimen from Tristan was aged at 18 years while similar-sized fish from Gough were only 11 years old. Because the populations at the two localities were not considered to be genetically isolated from one another, it was hypothesized that the difference in the growth rate and longevity was related to site-specific environmental conditions. Inshore sea temperatures were, on average. 3°C higher at Tristan than at Gough throughout the year. It is concluded that this temperature difference may affect growth rate indirectly through regulating diet and metabolic activity in S. capensis. Changes in reproductive strategy related to the level of environmental predictability at the two localities may also affect growth rate in this species. |
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