Offshore tuna longline fishery, which mainly targets bluefin tuna,
y e l l o w f i n t u n a , b i g e y e t u n a a n d a l b a d c o r e , i s o n e o f t h e
important offshore fisheries in Taiwan. Analyzable results from the
catches of tuna fishery and biological data are the important basis for
assessment and management of tuna resource, including fluctuations of the
catch and length-weight of tuna catching by the offshore longline fishery
and the recruitment of larva fish. The temporal-spatial variations of
these four tunas and the biology of tuna are researched in this study for
being the basis of management of tuna longline fishery .