Wakasagi (Hypomesus nipponensis) — identification, habitat & look-alikes

Wakasagi is a small, slender, silvery fish native to East Asia that lives in lakes and river mouths. Wakasagi has a small mouth and a tiny fin between its dorsal fin and tail.

Appearance

Appearance: It has a slim silver body, a small mouth, and a tiny fin between its dorsal fin and tail.

Look-alikes

Delta smeltHypomesus transpacificus

In a clear close-up of the underside of the head, wakasagi usually show a row of dark specks between the lower jaws; delta smelt have few or none there. The marks can be hard to see, so an ordinary photo may not settle the identification.

Why they get mixed upThe two are close relatives with very similar bodies.

Where it lives

Typical habitats: California reservoirs
Sacramento River watershed
Range: Introduced populations are established in California reservoirs and the Sacramento–San Joaquin watershed. The species is native to East Asia.
Preferred conditions: It can live in lakes and in fresh to water near river mouths.

Behavior

Diet: In California's Delta, it eats small drifting animals, including .

Life cycle

Breeding season: In the California Delta, wakasagi generally spawn a little earlier than delta smelt, though timing changes from year to year.
Reproduction: Wakasagi spawn in freshwater streams, attaching their eggs to rocks and gravel.

Name and classification

About the name: Wakasagi is also called Japanese pond smelt.

Conservation

IUCN Red List: LCLeast ConcernLow risk of extinction
Status: In California, wakasagi have hybridized with native delta smelt, although the impact on delta smelt is hard to measure.

Culture and stories

Culture and stories: California stocked wakasagi in reservoirs as food for sport fish.

11 sources