California sea hare

The California sea hare, Aplysia californica, is a species of sea slug in the sea hare family, Aplysiidae. It is found in the Pacific Ocean, off the coast of California in the United States and northwestern Mexico. Aplysia californica is found along the coast of California, United States, and northwestern Mexico (including the Gulf of California). Aplysia species inhabit the photic zone to graze on algae, mainly the intertidal, usually not deeper than 18–20 m (59–66 ft). The maximum length recorded for the California sea hare is 75 cm (30 in) when crawling and thus fully extended, although most adult specimens are half this size or smaller. Adult animals can weigh up to 7 kg (15 lb). A closely related species, Aplysia vaccaria, the black sea hare, can grow to be larger still. Like all sea hares, the California sea hare is hermaphroditic, acting as male and female simultaneously during mating. Aplysia are known to form mating chains with up to 20 animals. The eggs are yellow-green, and change after 8 to 9 days into a brown color before larvae hatch. Mating is most prominent during the summer month following the rise of the water temperature to 17 degrees Celsius. Aplysia has a generation time of 19 weeks: Day 1-37 after hatching from the egg planktonic stage, day 34-37 Metamorphic stage, day 45-80 juvenile stage (35 days in total). Reproductive maturity is reached 85 days after hatching (133 days after deposition of the fertilized eggs). The development of the nervous system lasts for a total of 140 days The life span is assumed to be around a year, yet older animals have been found. Cooler temperature delays spawning and has been shown to extend the lifespan.