grunion

Grunion are two species of the genus Leuresthes: the California grunion, L.

Grunion are known for their very unusual mating ritual. For the next ten days the grunion eggs remain hidden in the sand, but at the next set of high tides the eggs hatch and the young grunion are washed out to sea.

Natural history

Grunion were originally classified in Atherinidae, the family of silversides, but are now classified in the family Atherinopsidae, along with the other New World silversides, including the jacksmelt and topsmelt. The California grunion, Leuresthes tenuis, is found along the Pacific Coast from Point Conception, California, to Point Abreojos, Baja California. The Gulf grunion, L.

Young grunion grow very rapidly and are about five inches long by the time they are one year old and ready to spawn. Grunion adults normally range in size from 5 to 6 inches (13 - 15 cm) with a maximum size recorded at 8.5 inches (La Jolla Ca.,05-11-05(19 cm).

California grunion spawn at night on the beach, from two to six nights after the full and new moon, beginning a little after high tide and continuing for several hours. As a wave breaks on the beach, the grunion swim as far up the slope as possible. (The Gulf grunion spawns during the daytime, and has smaller eggs.)

Spawning may continue from March through August, with possibly an occasional extension into February and September. Grunion eggs can extend incubation and delay hatching if tides do not reach them, for an additional four weeks after this initial hatching time.

The hatching of grunion eggs can be watched by collecting a cluster of eggs after a grunion run and keeping them in a loosely covered container of damp sand in a cool spot for 10 - 15 days.

Grunion food habits are not well-known. Humans, larger fish, and other animals prey upon grunion. Some shorebirds such as egrets and herons prey on grunion when the fish are on shore during spawning. Seagulls, sea lions and sand sharks have also been observed feeding on grunion during a grunion run. The reduction of spawning habitat, due to beach erosion, harbor construction, and pollution is probably the most critical problem facing the grunion resource.

Tides, the phases of the moon, and grunion runs

Status of the population

Despite local concentrations, the grunion is not an abundant species.

Grunion fishing

In the 1920s, the recreational fishery was showing definite signs of depletion, and a regulation was passed in 1927 establishing a closed season of three months, April through June. The fishery improved, and in 1947, the closure was shortened to April through May. This closure is still in effect to protect grunion during the peak spawning period.

A fishing license is required for persons 16 years and older to capture grunion. Grunion may be taken by sport fishermen using their hands only. No appliances of any kind may be used to catch grunion, and no holes may be dug in the beach to entrap them. Grunion may be taken June 1 through March 31.

Suggestions for a good grunion run

The ends of long, unlit sandy beaches are often the best locations, and it helps to try to find a spot with fewer people. When there are too many grunion hunters, it is easy for the fish to be spooked and not come ashore. Have patience, since many people will give up after waiting for just an hour, even though there are several hours during which the grunion may run.

Cooking grunion

Grunion are moderately fatty and taste similar to smelt. You should remove the grunion's head, scales, and innards first before cooking. One suggestion is to roll the grunion in a mixture of flour and yellow corn meal with a little salt added.

History

The coastal Indians in California harvested grunion during spawning runs. Archeologists have found fossil grunion otoliths (tiny, bonelike particles or stony platelike structures in the internal ear of lower vertebrates) at various Indian campsites.

Grunion were mentioned by Spanish explorer Juan Cabrillo in his ship's log (circa 1542).

Scientists first identified grunion in San Francisco Bay in 1860 (Ayres, Proc.

Trivia