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| Stequert, B.; Conand, F.. |
| The age and growth of Bigeye tuna from the western Indian Ocean was investigated using both otolith and first dorsal spine. Microincrements, considered as daily depositions , were observed on transverse section of sagittal otoliths of 154 bigeye tuna (Thunnus obesus); they were counted to determine age and establish growth curve. The von Bertalanffy growth curve is FL = 303.9 (1 – e-0.000397 ( t+167.15)), where FL is fork length in cm and t in days. The fish reaches 58 cm at 1 year, 91 cm at 2 years and 120 cm at 3 years of age. We also studied growth by analysing marks on the first dorsal spine of 140 fish. For fish which are 1 and 2 years old, the results obtained with spine and otoliths are comparable, but they are different for older fish . 'Research... |
| Tipo: Proceedings Paper |
Palavras-chave: Age Growth rate Fishery biology Otolith ISW; Indian Ocean. |
| Ano: 1998 |
URL: http://hdl.handle.net/1834/71 |
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| Stequert, B.; Ramcharrun, B.. |
| From 281 females with fork lengths ranging from 43 to 73 cm and ripe ovaries, the batch fecundity of skipjack tuna (Katsuwonus pelamis) from the western part of the Indian Ocean was studied. Gilson's fluid, used as a preservative and dissociative agent for oocytes, has a strong and fast action (5 days) on the shrinkage of these oocytes. Counts made with a Dollfus box on sub-samples of dissociated oocytes show that, within a single sexual maturity period (February), the fecundity of skipjack tuna is the same whatever the geographic area: Mozambique Channel and South of Seychelles Islands. On the other hand, although sexual activity is noted for skipjack tuna throughout the year, individual fecundity changes with the season within a single area. This... |
| Tipo: Proceedings Paper |
Palavras-chave: Fecundity Sexual maturity Tuna fisheries Fishery biology Euthynnus pelamis ISW; West Indian Ocean. |
| Ano: 1996 |
URL: http://hdl.handle.net/1834/18 |
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| Fonteneau, A.; Marsac, F.; Pianet, R.; Stequert, B.. |
| This document attempts to develop an overview of the future needs for tuna research that should be recommended by the IOTC. Because of the spectacular increase of the tuna catches in the Indian Ocean during the last 15 years, it is necessary to conduct active research on the major stocks, giving a high priority to all research that will allow a reliable assessment of the stock status. A general problem in the tuna research conducted in the Indian Ocean is the lack of large-scale tagging programs. Such programs should be a priority in future Indian Ocean tuna research. Other research should also be conducted simultaneously upon various biological parameters which are fundamental to stock assessment. The fishery associated with artificial floating objects,... |
| Tipo: Proceedings Paper |
Palavras-chave: Catch/effort Purse seining Catching method ISW; Indian Ocean. |
| Ano: 1998 |
URL: http://hdl.handle.net/1834/61 |
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