Exploring predators of Pacific salmon throughout their life history: the case of Japanese chum, pink, and masu salmon

• Published in: Reviews in fish biology and fisheries Vol. 34; no. 3; pp. 895 - 917
• Main Authors: Okado, Jumpei, Hasegawa, Koh
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-09-2024; Springer Nature B.V
• Subjects: Adults; Aquatic mammals; Baleens; Bears; Biomedical and Life Sciences; Brackishwater environment; Carnivorous animals; Cerorhinca monocerata; Coastal zone; Environmental factors; Estuaries; Fish; Fish stocks; Freshwater & Marine Ecology; Freshwater fishes; Fry; Interspecific relationships; Juveniles; Lamna ditropis; Life history; Life Sciences; Marine fishes; Marine mammals; Oncorhynchus gorbuscha; Oncorhynchus keta; Oncorhynchus masou; Phalacrocorax carbo; Predation; Predators; Reviews; Rivers; Salmon; Species; Ursus arctos; Whales; Zoology; Japan; White-spotted charr; Salmonid; Citizen science; Mortality; Predator-prey relationship; Salmon shark; Survival; Rhinoceros auklet
• ISSN: 0960-3166; 1573-5184
• DOI: 10.1007/s11160-024-09858-y

When, where, and what predators prey upon salmon is fundamental to understanding their mortality in a given region. We reviewed the available information about predators of three Japanese Pacific salmon species throughout their life history: chum salmon
Oncorhynchus keta
, pink salmon
O. gorbuscha
, and masu salmon
O. masou
. Thirteen fish species, including seven salmonid species, and three avian species, such as great cormorant
Phalacrocorax carbo
, have been described as predators of fry/juvenile salmon in rivers. Predators of fry/juveniles in estuarine–coastal areas have been relatively well investigated and include 15 fish species, including young masu salmon, and five avian species, such as rhinoceros auklet
Cerorhinca monocerata
. Four large fish species, such as salmon shark
Lamna ditropis
, one baleen whale species, and pinnipeds are reported predators of subadults in the open sea. In the sea around Japan, including the Pacific, the Sea of Okhotsk, and the Japan Sea, we found evidence of predation on subadults, adults, unknown life-stage salmon by four pinniped species and three species of baleen and toothed whales. Adults returning to rivers were preyed upon by two mammal species including brown bear
Ursus arctos
and two raptor species. We also identified information gaps for specific predators by region and life stage. Collaborating with non-researchers to obtain observation records of predation on salmon is one method that could efficiently expand our knowledge of local predators. We further suggest using the information from our review to incorporate predation effects as well as environmental factors in models examining salmon stock fluctuation mechanisms.