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| Nishida, T.; Komatsu, T.. |
| Strengthening tuna management is one of the primary tasks for the new Indian Ocean Tuna Commission (IOTC). Stock assessment and the prediction of the dynamics of the tuna resources will become increasingly important research topics because they provide the basic information for the management decision process. Under these circumstances, this paper attempts to develop the stock analyses and prediction techniques using neural networks. As a first step and as a test study, analyses and predictions of catch rates of the Japanese yellowfin tuna longline fisheries are attempted. |
| Tipo: Proceedings Paper |
Palavras-chave: Fishery management; Stock assessment; Catch/effort; Tuna fisheries. |
| Ano: 1998 |
URL: http://hdl.handle.net/1834/60 |
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| Nishida, T.. |
| An examination is made of the possible impact of purse seine fisheries on the longline fisheries for the Western Indian Ocean yellowfin tuna (Thunnus albacares) stock. Past research works on fisheries interactions are reviewed and then descriptive (spatial and temporal) analyses are attempted for basic fisheries statistics (catch, CPUE and size). It was discovered that the general trends of longline CPUE are more or less constant in the whole purse seine fishing ground before and after purse seining started, while those in the heavy purse seine fishing grounds show a moderate decrease. This moderate decrease is discussed for 2 cases: the long-term situation and the immediate situation. |
| Tipo: Proceedings Paper |
Palavras-chave: Tuna fisheries Thunnus albacares Purse seining Longlining Catch/effort ISW; West Indian Ocean. |
| Ano: 1996 |
URL: http://hdl.handle.net/1834/17 |
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| Nishida, T.. |
| Yellowfin tuna (Thunnus albacares, YFT) in the Indian Ocean has been exploited for more than 200 years (Anderson and Hafiz, 1985), while official statistics are available for some 40 years. In this region, the YFT resource has been commercially important as a protein source for both developing and developed countries. Hence, it is essential to manage and conserve YFT resources properly for future generations. To this end, an assessment of the YFT stock is presented in this paper, in order to provide fundamental information for its management. More than 80% of the YFT catch from the Indian Ocean comes from the western part (Figure 1), so this assessment is focused on that part. In this study, the stock structure of the Indian Ocean YFT is assumed to be two... |
| Tipo: Report |
Palavras-chave: Tuna fisheries; Fishery statistics. |
| Ano: 1994 |
URL: http://hdl.handle.net/1834/520 |
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