Mysids: Mysida

Physical characteristics: Adults measure 0.59 to 0.98 inches (15 to 25 millimeters) long. The telson is wide and split at the tip.

Geographic range: In North America Mysis relicta is found in the Great Lakes of North America; Green Lake, Trout Lake, and Lake Geneva in Wisconsin; the Finger Lakes of New York; and a few Canadian shield lakes. It has been introduced into other lakes in the western United States, Alabama, and Maine. This species is also found in Europe, Scandinavia, and Russia.

Habitat: This species prefers to live in cold, freshwater lakes at temperatures of 39° to 57°F (4° to 14°C).

Diet: Mysis relicta is a filter feeder, a scavenger, and a predator.

Behavior and reproduction: This species moves up into open water at night and remains near the bottom during the day. They usually live in the dark; their eyes are easily damaged by strong light.

Mysis relicta are prey for many species of fish valued as food for humans. (© James H. Robinson/Photo Researchers, Inc. Reproduced by permission.)

Brood size is determined by the size of the female. Females measuring 0.51 to 0.59 inches (13 to 15 millimeters) carry 10 to 20 eggs, while females 0.66 to 0.82 inches (17 to 21 millimeters) carry as many as 25 to 40 eggs. The hatchlings remain in the marsupium for one to three months. They live a total of one or two years. Females reproduce once to twice in their lifetime.

Mysis relicta and people: Mysis relicta are prey for many species of fish valued as food for humans. These include lake trout, brown trout, rainbow trout, kokanee salmon, burbot, smelts, alewives, and others.

Conservation status: Mysis relicta is not considered endangered or threatened. ∎