Jellyfish in Pacific salmon food

Abstract

Ctenophores, hydroid jellyfish, appendicularians, salpas, and the pteropoda mollusk Clione limacina , conditionally combined into the group of “jellyfish”, are found in the food of all Pacific salmon — chum salmon, pink salmon, sockeye salmon, coho salmon and chinook salmon, but only in chum salmon their share is most significant, which is shown both absolute criteria (CHIN-private index of gastric filling of certain species and groups of jelly beans) and relative (share of jelly in the total INJ-general index of stomach filling). In food, chum salmon were present in 45.0 % of samples, pink salmon — 11.0 %, sockeye salmon — 7.0 %, coho salmon — 3.3 %, chinook salmon — 1.1 %. Chum salmon is well adapted to nutrition with jelly, because. has a stomach many times larger than that of other salmon, and in the diet of gelatinous it takes first place among them. Thus, in the event of a shortage of the main food (crustaceans, fish, squid), the chum salmon, due to the ability to consume and assimilate low-calorie food in large volumes, receives additional benefits in competitive relations with salmon and other pelagic fish.