Reference
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Leber, K. M.; Blankenship, H. L.; Arce, S. M.; Brennan, N. P. 1997. Influence of release season on size-dependent
survival of cultured striped mullet, Mugil cephalus, in a Hawaiian estuary. Fishery Bulletin
95(2):267-279 |
Abstract
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The concept that depleted populations of marine fishes can be revitalized by releasing cultured fish is being
tested in Hawaii. In this study we evaluated effects of interaction between release season and size-at-release on
recapture rates of cultured striped mullet, Mugil cephalus, released into Kaneohe Bay, Hawaii. Over
90,000 cultured M. cephalus fingerlings, ranging in size from 45 to 130 mm total length, were tagged with
binary coded-wire tags. Half were released in spring, the remainder in summer. In both seasons, releases were made
in three replicate lots. In each replicate, five size intervals of fish were released at two nursery habitats in
Kaneohe Bay. Monthly cast-net collections were made in 6 nursery habitats over a 45-week period to monitor recapture
rates, growth, and dispersal of cultured fish. Recapture rate was directly affected by the seasonal timing of
releases. Greatest recovery of the smallest fish released (individuals <60 mm) occurred following spring releases
and coincided with peak recruitment of similar-size wild M. cephalus juveniles. In contrast, recovery of fish
that were <60 mm at release was very poor after summer releases. Overall survival was similar at both release sites.
We hypothesize that survival of released cultured fish will be greater when releases are timed so that fish
size-at-release coincides with modes in the size structure of wild stocks. To optimize effectiveness of stock
enhancement as a fishery-management tool, pilot release-recapture experiments should be conducted to evaluate
effects of release season on size-dependent recovery of released animals. |