||Tunas are the ocean highly migratory species, Taiwan is the top countries of the|
tropical tunas fishery in the Indian Ocean, and the tropical tunas are the main target
species of our country in Indian Ocean. There were no systematic arrangement of
large-scale tuna longline fishery in the past. While assessing the resource assessment,
there are only few information included and discussed .The Purpose of this research
based on the large-scale fishing vessels’ logbooks, and analyzed the catch, CPUE and
fishing effort of tropical tuna longline vessels with geographical information system.
Discuss the dynamic patterns of tropical tuna vessels, and try to research the factors
influencing the vessels activities.
The research focus on the whole Indian Ocean, and utilizes the geographical
information system to analyze and research CPUE from 1970 to 2007(38 years) with
annual tropical tuna catch. Then, select the steady times of the fishery activities from
1999 to 2003 and carry on the analysis of catch data. Second, choose the first 20
fishing vessels of annual Yellow-fin tunas and Big-eye tunas with largest catch in this
period, regard these as the representative researching vessels. According to the
navigation route of each vessel, the results of the analysis are derived: 4 patterns of
Yellow-fin tuna, 3 patterns of Big-eye tuna. On the whole, there are 5 routes of
Taiwan fishing boat of tuna longline fishing vessels in the Indian Ocean: 1. The
fishing vessels go back to the equator across Arabian Sea from the equator. 2. The
fishing vessels go back to the equator across southern Indian Ocean from Arabian Sea.
3. The fishing vessels go back to the equator across the Bay of Bengal from the
equator. 4. The fishing vessels go back to the equator across the southern Indian
Ocean from the equator and stay near the equator during the whole year. Finally,
conclude that tuna longline fishery of Taiwan target tropical tunas in the Indian Ocean
are dominated by factors such as international fish price, climate, walrus and the
relationship with fishery cooperative countries, etc.. These factors lead to the 5 kinds
of vessel dynamic ways in the Indian Ocean.