Tag recovery locations of bigeye tuna tagged in the western Pacific (red circles), central Pacific (green circles) and easternPacific (blue circles). The small black circles represent the release locations within these areas.
A considerable amount of bigeye tuna tagging has been undertaken by the Pacific Community and the Inter-American Tropical Tuna Commission in recent years. This work has provided new insights into the extent of mixing of bigeye tuna across the tropical Pacific, both in the E-W and N-S directions (Figure 6). The key observation from these data is that bigeye tuna, at least during their juvenile stage, appear to be tightly constrained within the region from 10°N to 10°S. In previous bigeye tuna assessments, the boundary between the tropical and subtropical regions of the WCPO had been set at 20°N in the North Pacific and at 10°S in the South Pacific. This new information suggested that a boundary of 10°N in the North Pacific would be more appropriate. This boundary would also better demarcate the distribution of the purse seine fishery and better represent oceanographic provinces in the Pacific Ocean.
Click on the image to view an article which outlines the changes made in the 2017 bigeye tuna (Thunnus obesus) stock assessment conducted by the Oceanic Fisheries Programme (OFP) of the Pacific Community.