Relation of size at release of hatchery-reared black rockfish Sebastes inermis to survival in a Zostera belt around Ikuno Island, Hiroshima Prefecture, Japan

Abstract

To enhance the stock of black rockˆsh, Sebastes inermis, 2 cm-, 3 cm-and 5 cm-size groups of hatchery-reared sh were released in a Zostera belt around Ikuno Island after marking with ALC andˆn cut. The larger the size, the farther from the release point they were recaptured and the better the survival rate. Especially, most of the 2 cm-sizeˆsh had disappeared about one month later. A predation test in a terrestrial tank conˆrmed that the redˆn velvetˆsh Hypodytes rubripinnis was a dominant species as a predator at the release point, and signiˆcantly preyed on the 2 cm-size group more than the 3 cm-size group. According to changes of triglycerides in the muscle of 2 cmand 5 cm-size groups after release, it took about one month for releasedˆsh to acclimate to the natural conditions.

Effects of a tropical cyclone on the distribution of hatchery‐reared black‐spot tuskfish Choerodon schoenleinii determined by acoustic telemetry

“…To investigate differences in fish distribution changes between cyclone‐experienced (2007) and inexperienced groups (2006), both release years (2006 or 2007) and the L T of the fish were initially evaluated as time‐independent explanatory variables for estimating time to disappearance of the fish. The L T was included because size at release has been reported to significantly affect survival and dispersal (Tsukamoto et al , 1989; Murakami et al , 2005), and relatively large fish were released in 2007 compared to 2006. Akaike's information criterion with a second‐order correction for small sample sizes (AICc) was used to select the explanatory variables affecting the time to disappearance.…”

Structural complexity in relation to the habitat preferences, territoriality, and hatchery rearing of juvenile China rockfish (Sebastes nebulosus)

“…Declining populations have prompted programs aimed at protecting and bolstering wild stock (Parker et al 2000). Whether those efforts involve the preservation (Soh et al 1998) or creation (West et al 1994) of critical habitat, or intentional release of hatchery fish (e.g., Murakami et al 2005), knowledge of basic behavior is crucial (Curio 1996;Kramer and Chapman 1999).…”