Grunion The Gulf grunion, with its smaller eggs, is unique in that it spawn during both night- and daytime. Although some other fish species leave their eggs in locations that dry out (a few, such as plainfin midshipman, may even remain on land with the eggs during low tide) or on plants above the water (splash tetras), jumping onto land "en masse" to spawn is unique to the grunion, capelin and grass puffer. Grunion feeding habits are not well known. They have no teeth and feed on very small organisms such as plankton. In a laboratory setting, grunion eat live brine
Grunion research points to a restricted resource that is adequately maintained at current harvest rates under existing regulations. In the 1920s, recreational fishing of grunion caused definite signs of depletion resulting in a regulation passed in 1927 that established a closed season of three months from April until June. Grunion stocks improved and in 1947 the closed season was shortened to the months of April and May. This closure is still in effect to protect grunion during their peak spawning period. The periodic appearance of the grunion on Southern California beaches, and the act of catching them, is locally known as