Grunion classified in the family Atherinopsidae along with other New World silversides including the jacksmelt and topsmelt. The California grunion, "L. tenuis", is found along the Pacific Coast from Point Conception, California, to Punta Abreojos, Baja California Sur. They are rarely found between San Francisco in the north and San Juanico Bay, Baja California Sur, in the south. The Gulf grunion, "L. sardina", is found along the coast of Baja California in the Gulf of California. Inhabiting the nearshore waters from the surf to a depth of , marking experiments indicate they are not migratory. They are small, slender fish with
USS Grunion the Pacific on 24 May. A week later, as she transited the Caribbean Sea for Panama, she rescued 16 survivors of the USAT "Jack", which had been torpedoed by the , and conducted a fruitless search for 13 other survivors presumed to be in the vicinity. Arriving at Coco Solo on 3 June, the "Grunion" landed the survivors and continued on to Pearl Harbor, arriving on 20 June. Departing Hawaii on 30 June after ten days of intensive training, the "Grunion" touched Midway Island before heading toward the Aleutian Islands for her first war patrol. Her first report, made as