Creature Feature: California Grunion

The California grunion is usually found south of Morro Bay, but they have been taken on occasion as far north as San Francisco Bay. Most often they school a short distance from shore in 15 to 40 ft. of water.

Distinguishing Characteristics

  • Bluish-green above, silvery below
  • Bright silvery-blue band, bordered with violet on the upper margin, runs the length of the body
  • Body elongate; mouth small
  • Scales small, smooth, and firm
  • Two dorsal fins, the first with spines; no adipose fin

Life History & Other Notes
The spawning behavior of the California grunion is one of the most unusual of all marine fishes. They are the only California fish known to strand themselves on the beach to deposit their reproductive products in the moist sand. Females, accompanied by up to eight males, swim with waves washing onto the beach, dig into the sand up to the pectoral fins, and lay eggs. The male wrap themselves around the female and fertilize the eggs. With the next wave, the fish return to the sea. Spawning takes place from early March through September, and then only for three or four nights following the full or new moon immediately after high tide. Most females spawn from four to eight times per year, and may produce up to 3,000 eggs every two weeks.

CDFW publishes a schedule of predicted grunion runs on its website. Observing a grunion run is fascinating, and the fish are also good eating.

 California Grunion Quick Facts:

Scientific Name: Leuresthes tenuis

Other Common Names: little smelt, lease smelt

Range & Habitat: Morro Bay south in surf environments

Length & Weight: To 7+ in. and less than 2 oz.

Life Span: To 4 years

Diet/Fishing Information: Feeds on small crustaceans and fish eggs. Generally caught during spawning runs – by law, may only be taken by hand

Excerpt from the California Finfish and Shellfish Identification Book.

Single copies of the book are available to California residents free of charge by emailing a request to