Grunion The normal lifespan of the grunion is three to four years, although individuals up to five years old have been found. Their growth rate slows after the first spawning and stops completely during the spawning season. Consequently, adult fish grow only during the fall and winter. This growth rate variation causes annuli to form on the scales, which have been used for determining ages. California grunion spawn on beaches from two to six nights after the full and new moon beginning soon after high tide and continuing for several hours. As a wave breaks on the beach, the grunion swim
USS Grunion she patrolled north of Kiska Island, stated she had been attacked by a Japanese destroyer and had fired torpedoes at her with inconclusive results. She operated off Kiska throughout July and sank two enemy patrol boats as she waited for enemy shipping. On 30 July, the submarine reported intensive antisubmarine activity and was ordered back to Dutch Harbor. The "Grunion" was never heard from again. Air searches off Kiska were fruitless, and on 5 October the "Grunion" was reported overdue from patrol and assumed lost with all hands. Her name was stricken from the Naval Vessel Register on 2 November