In 2002, Kinki University succeeded to culture bluefin tuna for the first time in the world. Last October it released 1,862 juvenile bluefin raised by aquaculture into the sea off Japan’s Wakayama Prefecture. The juveniles are third generation tuna raised from the eggs in a pen. So, they have no relationship whatsoever with wild fish.
Each fish was marked with a tag. Among them, a special tag for recording the water temperature, depth, migration route etc. was attached to 11 fish. Reportedly, 8 among the total 1,862 fish tagged were captured 30-45 days after their release. However, no special tag was recovered. Still, the results at least prove that bluefin tuna raised by artificial means can survive at sea.
From the viewpoint of a scientist, it seems that a new stage of bluefin tuna aquaculture has started. Namely, in the near future aquaculture may become a useful means to recover a stock which is overfished. There are still many problems to be solved including the impact on biodiversity, genes, etc. caused by the release of cultured fish into the sea, but I hope the study makes good progress to realize aquaculture’s usefulness soon.