鳥取県沿岸浅海域に放流したヒラメ人工種苗の被食 Predation by Fishes on Hatchery-reared Japanese Flounder Paralichthys olivaceus Juveniles Released in the Coastal Area of Tottori Prefecture
Stomach contents of piscivorous fishes were examined to investigate their predation pressure on hatchery-reared Japanese flounder released in the coastal areas of Tottori Prefecture (1989-1991). Released flounder were taken frequently by 1-age group Japanese flounder, bartail flathead and sea bass primarily during the early days after release. We observed few incidences of predation on wild flounder juveniles by piscivorous fishes in the same study area. This suggests that reared juveniles are more vulnerable to predation than wild flounder due to behavioral differences. Abundance of 1-age group Japanese flounder and flathead in the area was estimated from May to July by counting by divers. Cumulative predation estimated from stomach content analysis and abundance of predatory fishes accounted for a substantial part of the estimated mortality. Other potential sources of mortality, particularly predation by nocturnal predators, are discussed.
日本水産学会誌 64(1), 1-7, 1998-01-15