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.