| 英文摘要 |
Catch and effort data of Taiwanese longline fishery to fish bigeye and yellowfin tunas in the Atlantic and bluefin tuna in the Pacific are the essential ones for standardizing abundance index and assessing stock status. However, several analyzed models result in that the data above mentioned for Atlantic tropical tunas were not informative, or high overestimation of standing stock status with these data applied. However, in order to comply with the schedules of bigeye and yellowfin tunas stock assessment, recommendation of data assessment and building of assessment models by International Commission for the Conservation of Atlantic tunas, programming, verifying and developing Taiwanese longline indices for both species to incorporate with other indices provided by other fishing nations in pursuing stock status assessments of tropical tunas are the most important tasks. Meanwhile, the same tasks are applied to verify and integrate the fishery data of bluefin tuna from different sources. The research includes double-check and debug of logbooks by the principles investigated in 2009 works for separating the attributes of catch frequency distribution, and by investigating the attributes of each record of logbooks in relation to vessels and fishing grounds. Then, the step regression analysis and deviance analysis are applied to investigate factors and weights of influencing abundance index. Accordingly, the differences of individual fishery attributes and influence of weighted index affected by factors could be applied to standardize abundance index of individual fishery by the investigation of factor weights. Finally, Taiwanese longline tropical indices in the Atlantic Ocean are verified and could be used in the assessment sessions, and provide to the assessment by conservation and management organizations and to participate 2010 workshops to collect the assessing results. Also in order to collect the Pacific bluefin stock status information, the data collected will be submitted to and participate the International Scientific Commission for the stock assessment of tunas and tuna-like species in the North Pacific Ocean. Those results are the fundamental basis of tropical tunas management and tuna fishery development |
