Endangered Riverside fairy shrimp discovered at Costa Mesa park

A biologist in the city of Costa Mesa has discovered another winner of this year’s abundant rains: a tiny crustacean known as the Riverside fairy shrimp. Tony Bomkamp found the endangered species in a vernal pool in Costa Mesa’s Fairview Park. 

The pool joins just a handful of spots in Southern California where the species is known to exist.

Riverside fairy shrimp, which max out at about one-and-a-half inches long, are uniquely adapted to California’s boom or bust precipitation cycle. The eggs of fairy shrimp hang out on the dry bottom of seasonal pools for years. When the pools fill up with rain water, they pop out, grow, mate and then die when the water evaporates.

Then the eggs wait around for another rainy year.

Bomkamp has been monitoring the vernal pools at Fairview Park for more than 20 years. He knew they were home to another endangered species, the San Diego fairy shrimp, but this is the first year he’s seen their relatives, which hatch later in the season.

"It’s exciting from a conservation standpoint because the pools at the park are already protected because they already have a listed [endangered] species [the San Diego fairy shrimp]." Now there are two, known endangered species in the pools.   

Ileene Anderson, a biologist with the Center for Biological Diversity, said fairy shrimp are an important food source for migratory birds. But their habitat has shrunk over decades of intense development in Southern California.

“[Vernal] pools are really unique features now on the landscape, there’s just not that many of them left around,” she said. 

The Riverside fairy shrimp was listed as an endangered species in 1993. The U.S. Fish and Wildlife Service designated some 1,700 acres as critical habitat for the species in 2012, in Orange, San Diego and Ventura counties. 

Bomkamp said the vernal pools at Fairview Park only fill up about twice a decade. Visitors can see the pools and, with luck, the fairy shrimp but the pools are fenced off to protect the habitat.