Grunion shrimp. An isopod, two species of flies, sandworms, and a beetle have been found preying on the eggs. Some shorebirds such as egrets and herons prey on grunion when the fish are on shore during spawning. Seagulls, sea lions, and larger fish such as 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 believed to be the most critical problem facing the grunion species. Despite local concentrations, the grunion is not an abundant species. While the population size is not known, all
USS Grunion the exact location indicated by the commander of the "Kano Maru". The sunken object had many characteristics typical of a submarine. In 2007, using a ROV, DSSI/Oceaneering returned to the site and took video recordings of the imploded remains of a submarine, which had markings in English, and propeller guards and limber holes identical to those of the "Grunion". The following year, the US Navy confirmed that the find was the "Grunion". Although it is not absolutely certain, the evidence strongly suggests that the "Grunion" was lost as a result of multiple torpedo failures during her encounter with the "Kano