Effects of release size on survival and growth of Japanese flounder Paralichthys olivaceus in coastal waters off Iwate Prefecture, northeastern Japan

Abstract

A total of 35900 in 1990 and 73400 in 1991 otolith-marked, hatchery-raised Japanese flounder Paralichthys olivaceus fry ranging from 4 to 15 cm total length (TL) were released into shallow water at depths of 4 to 8 m at Ohno Bay, northeastern Japan. The otoliths of the fish were marked 1 to 3 d prior to release with an alizarin complexone fluorescent marker The size at release of flounder recaptured by a beam trawl, set net and commercial catch was estimated using the fluorescent mark diameter to TL relationship, and survival and growth rates were examined. As time progressed after release, back-calculated release size distributions gradually shlfted to larger values. The flounder fry > 9 cm at release were successful in recruiting to commercial fisheries. The major cause of mortality was thought to be predation by large flounder and greenling Hexagrammos otaku whlch were abundant in the flounder nursery ground. Growth rate of released flounder was high in the warm and low in the cold season. Individual growth rates were estimated by otolith mark diameter and TL at catch. The relationship of release size and growth rate analyzed in the flounder recaptured 1 1 mo after release indicated that survival of released flounder is strongly associated with size itself and growth rate in the field.

Pilot evaluation of summer flounder stock enhancement potential using experimental ecology

“…emigration at or near the size-at-release may be tantamount to mortality). Seventh, HR individuals of the closely related Japanese flounder Paralichthys olivaceus suffer rapid (on a scale of days) and extensive post-release mortality, most likely due to predation (Yamashita et al 1994, Furuta 1996, Furuta et al 1997. These 7 pieces of evidence suggest that the rapid disappearance of HR fish from release sites was due to within-site mortality of released fish, and not to emigration.…”

Primera liberación de juveniles de mero <i>Epinephelus marginatus</i> (Lowe, 1834) (Serranidae: Teleostei) cultivados en criadero en arrecifes artificiales en el mar Mediterráneo: resultados de un estudio experimental

“…In several stocking experiments with reared fishes, both survival after release and recapture rate increased with increasing size at release (Tsukamoto et al, 1989;Kristiansen et al, 2000). The positive effect of fish size was frequently associated with a critical size as a consequence of selective predation on small fish (Tsukamoto et al, 1989;Yamashita et al, 1994). On the other hand, smaller individuals seemed more able to adapt to the natural feeding resources (Tsukamoto et al, 1995).…”

“…The influence of size at release on survival of fish in the wild is still one of the most controversial topics of stock enhancement (Tsukamoto et al, 1989;Yamashita et al, 1994;Otterå et al, 1999;Kristiansen et al, 2000;Svåsand et al, 2000). In several stocking experiments with reared fishes, both survival after release and recapture rate increased with increasing size at release (Tsukamoto et al, 1989;Kristiansen et al, 2000).…”

The Extent and Spatial Scale of Connectivity Among Reef Fish Populations: Implications for Marine Protected Areas Designated for Fisheries Enhancement

“…To date, this technique has primarily been used to quantify survival of hatchery-reared fish, as well as to validate daily increment deposition on otoliths, which then can be used to age fish (Geffen 1992, Yamashita et al 1994, Secor et al 1995. However, in the only larval fish tagging study attempted in a marine system, Jones et al (1999) used this technique (i.e., oxytetracycline marking of embryos in nests) to demonstrate that retention (self-recruitment) of a damselfish, Pomacentrus amboinensis, to reefs at Lizard Island (Great Barrier Reef) might be equally, if not more, important than larval immigration to the reefs.…”