Euphausia pacifica
FAMILY
Euphausiidae
TAXONOMY
Euphausia pacifica Hansen, 1911.
OTHER COMMON NAMES
Japanese: Isada.
PHYSICAL CHARACTERISTICS
About 0.75 in (1.9 cm) long, weighing about 0.003 oz (0.1 g).
DISTRIBUTION
North Pacific Ocean, from North America to Japan.
HABITAT
Open water, beyond the continental shelves or at their edges. Observed from the surface to about 984 ft (300 m) in depth.
BEHAVIOR
Migrates vertically to the food-rich sea surface in the early part of the night, feeds, and then sinks again upon satiation. Tends not to feed during the day even if food is relatively abundant below the surface.
FEEDING ECOLOGY AND DIET
Diet consists of phytoplankton and zooplankton. Predators include salmon, cod, herring, halibut, rockfish, whales, and seabirds.
REPRODUCTIVE BIOLOGY
Lifespan is about two years, somewhat longer for females. In general, females take part in two spawning seasons, while males take part in only one.
CONSERVATION STATUS
Not listed by the IUCN. One of the most common krill species along the west coast of North America.
SIGNIFICANCE TO HUMANS
Studies have been done to determine the feasibility of establishing fisheries off the California coast; this species makes up about 70% of the harvest of a controlled active krill fishery in British Columbia, products of which are mainly used in fish feed for aquaculture and aquaria. Also fished commercially off the coast of Japan.
