Optimal Release Locations of Juvenile Ocellate Puffer Takifugu rubripes Identified by Tag and Release Experiments

Abstract

We identified the optimal location for releasing hatchery-produced juveniles of ocellate puffer (Takifugu rubripes) for stock enhancement by tag and release experiments. The fish were released at four areas, Suruga Bay, Enshu Nada, Ise Bay, and Kumano Nada, along the central coast of Honshu Island in Japan from 2001 to 2005. Approximately 10,000–40,000 cultured puffer fish were released in these areas in 23 groups. Tagged fish were mainly recaptured at age 0 by small-scale trawl net fishing in Ise Bay, and by longline fishing at age one or older in Suruga Bay, Enshu Nada, and Kumano Nada. Overall average recapture rate yielded 13.0% for the Ise Bay release group compared with 2.0%, 2.9%, and 0.7% for the Suruga Bay, Enshu Nada, and Kumano Nada release groups, respectively. Even in the Ise Bay area, significant differences in recapture rates were observed among three release locations. Lower recapture rates were presumably caused by predation, because tagged fish were found in the intestines of Japanese sea bass (Lateolabrax japonicus). It is suggested that release locations should be carefully evaluated and chosen to reduce initial mortality even if cultured ocellate puffer are released in Ise Bay. One of the optimal release locations is specified in shallow areas, such as off Tokoname, which are inhabited by wild juvenile ocellate puffer.

Keywords:

• ocellate puffer
• Takifugu Rubripes
• stock enhancement
• release strategy
• habitat-dependent mortality

ACKNOWLEDGEMENTS

This study was supported by the Fisheries Agency in Japan. We wish to thank two anonymous reviewers for their helpful comments.