Shrimp hunt threatens housing

A massive housing development in Paso Robles could be waylaid for another two years so biologists can search for tiny endangered shrimp.

Vernal pool fairy shrimp, usually about an inch in size, could be living on 500 acres of land near Meadowlark and Creston roads where developers want to build. But first developers must determine whether certain federal permits and rules to protect the crustaceans apply. The developers will fund and award the biologist contract independently, estimated for up to $35,000. City staff will advise.

In December, the long-stalled Olsen Ranch and Beechwood developments calling for 1,300 new homes finally regained traction after a three-year standstill because of delays in a citywide traffic plan. If fairy shrimp are found, planners say the projects could go forward if approved, but building around the habitats could impact design.

The crustaceans in question live in seasonal freshwater puddles and pools that usually form after rainfall. After the water dries up, the shrimp eggs can survive in little cysts in the soil until they hatch when the pool forms again the next season.

One study has shown that a fairy shrimp egg sack can remain viable for up to 20 years in dry soil, said David Wolff, the San Luis Obispo-based Sage Institute’s principal ecologist.

“It’s a pretty cool evolutionary thing,” he added. “They’ve really hedged their bets over time.”

The shrimp has been found locally before, including off Highway 46 East in Paso Robles and in San Luis Obispo. In fact, their discovery off Tank Farm Road in 2004 posed a threat to construction of the San Luis Obispo Costco store about a mile away. But studies later showed none were found at the site.

Because vernal pools exist seasonally, it can take time for biologists to confirm what lives in them. The U.S. Fish and Wildlife Service requires they follow a certain protocol and repeat it during the wet and dry seasons. Because of this, it could take one to two years to determine whether the shrimp exist on the Olsen Beechwood property.

After a rain, the biologist would search for shrimp by wading through the pool with a net and cataloging the finds. In the hot months, numerous soil samples are required to search for eggs.

The eggs can survive in the dry dirt because female fairy shrimp form a chemical reaction around their egg sacks that create a cyst casing to protect them, Wolff said.

“They’re bigger than a grain of sand and look like orange golf balls,” he added.

Once back in the water, the shrimp typically have a lifespan of up to 90 days to hatch and grow.

“It’s a unique ecosystem full of life,” Wolff said.

Vernal pool fairy shrimp were placed on the federal endangered species list as threatened in 1994 as a result of a dramatic loss of vernal pool habitats from agriculture and urban development, Wolff said.

They are vital, he added, providing food for shorebirds and balancing habitats for freshwater aquatic life. Locating them can often be a surprise. Because the egg cysts can pass through the digestive systems of birds and be OK, he said, they could travel to different areas.