Local university and homeowners association work to eradicate the nonnative predator to save frogs and newts.
By P.G. O’Malley/Special to The Malibu Times
Malibu West homeowners have joined forces with Pepperdine University and the National Park Service to help restore Trancas Creek, which flows toward the ocean on the eastern boundary of the subdivision.
“It’s our stream, ” Malibu West Manager Sherry Lee said. “We help them whenever they need help.”
Project director Dr. Lee Kats said the problem is not pollution, but a bad case of an introduced predator that is gobbling up eggs and young of two California species of concern that make their home in the creek, the diminutive California frog and the California newt, a red-colored salamander.
“It’s a clean water issue in that the frog and California newt are important to the balance in streams, which is important to water quality,” said Jo Kitz of the Mountains Restoration Trust, which helped facilitate the grant for the three-year project. “And just as it’s important to preserve plants and animals that are native to an area, it’s also important to preserve the aquatic life of streams, which are part of an ecosystem’s food chain.”
The culprit in this case is crayfish, which are native to Mississippi but are used locally as freshwater bait and typically infect a stream when fishermen dump what they don’t use wherever they’re fishing. In addition to Trancas Creek, both Malibu and Topanga creeks are infected. In the case of Trancas Creek, Kats also thinks there’s a renewable source of crayfish coming from the irrigation ponds at Malibu Country Club, a golf course located further up in the Santa Monica Mountains, which he says were once stocked with bass. He’d like to see the golf course drain the ponds and remove the crayfish.
NPS Natural Resource Specialist Gary Busteed says it’s logical to assume the golf course is a source since crayfish are found all the way up the stream and “crayfish don’t usually disperse uphill.”
A spokesperson for Malibu Country Club said as far as he knows the three irrigation ponds the golf course maintains hold a few catfish and some bluegill. He said so far no one from Pepperdine or the NPS has approached them about crayfish.
Because it’s next to impossible to keep the lobster-like crayfish out of the creek (99 percent were washed out to sea in the 1997 El Niño winter, but the remaining one percent have multiplied to make the breeding season miserable for the newts and the frogs), Kats and the volunteers from Malibu West have concentrated on trapping the interlopers and constructing barriers to create crayfish-free zones during the time when the frogs and newts lay eggs. So far Kats reports that in parts of the stream where the crayfish have been trapped, frog production has jumped by a factor of four.
“We conservation biologists are always saying this is a problem, that is a problem. But this project gives us something to be positive about,” Kats said.
His goal for his efforts is to maintain healthy frog and newt populations for at least 20 years. So far, 1,400 crayfish have been removed from Trancas Creek and fed to foundlings in the wildlife rehabilitation center in Monte Nido.
“There isn’t an established protocol for crayfish removal,” Busteed said. “We need some kind of strategy. What’s going on in Trancas Creek will provide a foundation for how to go about eradication.”
Meanwhile, Lee said the project has been great education for Malibu West children. “This kind of thing teaches them about the environment, and hopefully they’ll pass it on.”