Challenges for Diadromous Fishes in a Dynamic Global Environment

Feeding and Prey of Pacific Lamprey in Coastal Waters of the Western North Pacific

Alexei M. Orlov, Richard J. Beamish, Andrei V. Vinnikov, and Dmitry Pelenev

doi: https://doi.org/10.47886/9781934874080.ch66

Pacific lamprey Lampetra tridentata is an endemic parasitic species widely distributed in the North Pacific Ocean. The known range of this species is from northern Hokkaido (Japan) and southern California (USA) to the northern Bering Sea. There is evidence that Pacific lamprey extended its range southward during recent years to central Honshu (Tochigi prefecture, Japan) and Mexico (Santo Domingo River).

Pacific lamprey plays an important and manysided role in the marine and freshwater ecosystems of the North Pacific. On the one hand, it is consumed by a variety of aquatic animals, from river crayfishes to piscivorous birds, and marine mammals. On the other hand, Pacific lamprey is a parasite of many fishes, and even of whales, affecting commercial fish stocks, including those of Pacific herring Clupea pallasii, Pacific hake Merluccius productus, Pacific cod Gadus macrocephalus, walleye pollock Theragra chalcogramma, salmons Oncorhynchus spp., rockfishes Sebastes spp., Pacific halibut Hippoglossus stenolepis, Greenland halibut Reinhardtius hippoglossoides, Kamchatka flounder Atheresthes evermanni, and arrowtooth flounder A. stomias. Pacific lamprey became more abundant recently in the North Pacific, based on the number of marks on host species, and its effect on commercial fish stocks will notably increase if the population continues to increase. Although this species is of some interest for fisheries, it is currently fished in limited amounts in Oregon (USA) waters only.

The freshwater life of Pacific lamprey is well known, but data on the sea period of life, when Pacific lamprey is parasitic, is scarce (Novikov 1963; Abakumov 1964; Scott and Crossman 1973; and Beamish 1980). There is a large number of host fish species known for Pacific lamprey. However, its selectivity in respect to species, size, sex of prey, and the character of wounds (sizes and location on the body) are studied insufficiently.