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Otoliths and vertebrae as potential hard structures for ageing South African yellowfin tuna Thunnus albacares
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: JD Filmalter --- Department of Ichthyology and Fisheries Science, South Africa OLF Weyl --- Department of Ichthyology and Fisheries Science, South Africa W Sauer --- Department of Ichthyology and Fisheries Science, South AfricaSagittal otoliths and vertebrae from 46 yellowfin tuna Thunnus albacares (118-175 cm fork length) collected off the west coast of South Africa were assessed for potential usefulness in age estimation. Growth increments were found on both structures. Comparisons of growth... -
Age and growth of redeye round herring Etrumeus whiteheadi off the South African coast
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: Y Geja --- Branch Fisheries Management, Department of Agriculture, Forestry and Fisheries, South Africa MD Durholtz --- Branch Fisheries Management, Department of Agriculture, Forestry and Fisheries, South Africa CL Moloney --- Zoology Department and Marine Research Institute, South AfricaAges of redeye round herring Etrumeus whiteheadi were estimated with associated errors and used to infer life-history information, such as age composition, age-at-maturity and instantaneous mortality rate. Samples were collected in November 2005 during a research survey aimed at estimating... -
Age and growth of Nile tilapia Oreochromis niloticus (Linnaeus, 1758) from Lake Tana, Ethiopia
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: A Degsera --- , Ethiopia M Minwyelet --- , Ethiopia T Yosef --- , EthiopiaAge and growth of Nile tilapia, Oreochromis niloticus, from Lake Tana were studied from June 2016 to May 2017. In total, 1 597 otoliths were collected from three representative sampling sites for macrozone analysis. Otoliths were ground and examined under... -
Population ecology of Psammobates oculifer in a semi-arid environment
Item type: Journal Article • Journal: African Journal of Herpetology • Authors: Toby Keswick --- , , South Africa Margaretha D. Hofmeyr --- , , South AfricaWe studied the ecology of Psammobates oculifer over 13 months near Kimberley, South Africa, to ascertain if the population's life history traits conform to chelonian patterns in arid environments. Capture rates were highest in spring and lowest in winter when...