Acclimatization of hatchery-reared small tiger puffer Takifugu rubripes juveniles released in the estuary area
2017
Yoshida, A. | Suzuki, S. | Imanaka, S. | Yamauchi, S.
In order to clarify the post-release acclimatization of hatchery-reared small tiger puffer Takifugu rubripes juveniles, we released 20,000-61,000 tails / year (average total length 36.5-44.4 mm) of hatchery-reared fish during 2011-2015, in early June every year, in the Ota River estuary (Iwata City, Shizuoka Prefecture). Subsequently, we examined acclimatization using the beach seine. The number of captured fish was 28-155 tails / year, totaling 541 tails. Feeding on natural food was observed in majority of the captured fish three days after release. Estimated daily growth amount was equivalent to that of natural fish, and the condition factor also showed no decreasing trend. These findings suggested that the released fish grew steadily with the initiation of feeding just after release, and that their nutritional status was stable. In addition, their burrowing behavior just after release, and the recovery of a missing caudal fin confirmed that they had acquired the escape / burrowing ability. Consequently, it was inferred that even hatchery-reared small tiger puffer juveniles acclimatize smoothly due to release at suitable sites.
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