Do Pacific salmon (Oncorhynchus spp.) steal bait from surface longlines at sea?
By Kazuya Nagasawa, Kazuaki Tadokoro
Fisheries Research, Volume 26, Issues 3-4, May 1996, Pages 381-384, ISSN 0165-7836, DOI: 10.1016/0165-7836(95)00454-8.
Examination of stomach contents of Pacific salmon (Oncorhynchus spp.) caught with surface longlines in the Bering Sea revealed that baitfish, Japanese anchovy Engraulis japonicus, was frequently found in the stomachs. The percentage occurrence of baitfish found in salmon stomachs did not differ significantly between species: chum (Oncorhynchus keta, 19.2%), pink (Oncorhynchus gorbuscha, 17.5%), sockeye (Oncorhynchus nerka, 17.5%), and chinook salmon (Oncorhynchus tshawytscha, 30.0%). When baitfish was/were observed in the salmon stomachs, usually one anchovy was present, but the stomach of one chum salmon contained six anchovies. During longline retrieval, one salmon (species unknown) was observed to remove the anchovy from the hook without becoming hooked. It is thus concluded that salmon are successful in stealing baitfish from longline hooks for a short soaking period (about 1 h).
Keywords: Bait stealing; Surface longline; Pacific salmon Oncorhynchus spp