日本沿岸水域における魚類と海鳥類によるサケ幼稚魚の捕食 <総説>

Predation by Fishes and Seabirds on Juvenile Chum Salmon (Oncorhynchus keta) in Coastal Waters of Japan : a Review

Nagasawa Kazuya

Kaeriyama Masahide

北海道さけ・ますふ化場研究報告

This review examines available literature on the fauna and diets of fishes and seabirds in coastal waters of northern Japan from spring to summer and discusses the impact of fish and seabird predation on chum salmon (Oncorhynchus keta) populations in Japan. Over 90 fish species have been reported to occur with chum salmon juveniles. Among these species, fishes recorded as predators are only 4 species: Japanese dace (Tribolodon hakonensis) at estuaries, and Arabesque greenling (Pleurogrammus azonus), Japanese flounder (Paralichthys olivaceus), and pink salmon (O. gorbuscha) at sea. Fish predation may cause substantial loss of juveniles at sites where these fishes, particularly Arabesque greenling and Japanese dace, are abundant. However, there is no evidence that fish predation has much impact on the number of returning adult salmon in Japan. The release of hatchery-reared, large-sized juveniles possibly reduces the mortality by fish predation. Rhinoceros auklets (Cerorhinca monocerata) and black-tailed gulls (Larus crassirostris) have been recorded as predators of juvenile chum salmon. These seabirds breed abundantly in northern Japan, and the impact of their predation on Japanese chum salmon populations may be significant. More field and experimental work is needed to evaluate the mortality of Japanese chum salmon juveniles caused by predation by fishes and seabirds.

90種以上の魚類が日本沿岸水域でサケ幼稚魚と一緒に分布するが, サケ幼稚魚の捕食者と認められたのは汽水域でウグイ, 海洋でホッケ, ヒラメおよびカラフトマスの4種のみであり, 日本沿岸域におけるサケ幼稚魚の魚類による捕食減耗は著しく少ないと推定される. 一方, 海鳥類のウトウとウミネコはサケ幼稚魚の有力な捕食種と考えられ, 繁殖期のウトウは幼稚魚を雛の餌とするし, ウミネコの分布域と幼稚魚の分布はよく重なる.

サケ

稚魚

幼魚

捕食

魚類

ウグイ

ホッケ

ヒラメ

カラフトマス

海鳥類

ウトウ

ウミネコ

日本沿岸

総説

Zoology [ 480 ]

jpn

水産庁北海道さけ･ます･ふ化場

Copyright (c) 1995 独立行政法人水産総合研究センター さけますセンター

[ISSN] 0441-0769

[NCID] AN00229676

[URI] http://salmon.fra.affrc.go.jp/kankobutu/srhsh/data/srhsh366.htm isVersionOf