The U.S. Fish and Wildlife Service last week listed critical habitat for Riverside fairy shrimp, a small endangered crustacean that lives in seasonal ponds in Southern California.
The service identified 1,724 acres of essential habitat for the shrimp in parts of Ventura, Orange and San Diego counties. About half of that land is in the Otay Mesa area.
The rule published in the Federal Register represents the service’s third stab at laying out critical habitat for the shrimp.
Two earlier efforts in 2000 and 2005 were challenged, the first time by developers and then by environmentalists.
The half-inch to inch-long shrimp live in “vernal pools,” which fill with water during rainy seasons and disappear in dry weather.
“They only fill with water during certain times of the years, but they harbor an incredible number of species,” said Jane Hendron, public affairs chief for the service’s Carlsbad office.
The shrimp serve as a food source for waterfowl and other larger animals. Their eggs lie dormant in the soil during dry spells but hatch when the pools refill.
During the last century, the vast majority of vernal pools disappeared for good, displaced by urban growth.
“These nice flat areas with rolling topography where the water could pond during rains were also the most favored areas for development,” Hendron said. “Over time, much of what would have been vernal pool areas were developed.”
The shrimp were listed as endangered in 1993.
The final version of the habitat listed in the Federal Register, Hendron said, is “not nearly as much as we designated in 2000 but more than in 2005.”