Who knew? I certainly did not until I read this mornings Los Angeles Times. But crayfish are killing native species throughout the Malibu Creek Watershed.
Apparently crayfish were introduced by anglers who used them as bait and now the nonnative 3-inch-long crayfish that have colonized and multiplied in the 109-square-mile Malibu Creek watershed over the last century. But a 29-year-old biologist, Kyle Troy with the nonprofit Mountains Restoration Trust has come up with a plan, funded by a grant of $600,000.00 from the California Department of Fish and Wildlife, using volunteer students from local schools to get rid of the crayfish from the Santa Monica Mountains’ streams and rivers within three years.
Troy's plan to rid the watershed of crayfish is part of a bigger plane in southern California to transform the watershed’s ecological system into a more natural state, in hopes that the endangered steelhead trout can make their way back to historic spawning grounds. The estimated 500 Southern California steelhead left on our planet are scattered across coastal waters between San Luis Obispo in central California and the U.S./Mexico border.
“Crayfish are incredibly aggressive, and omnivorous,” Troy said. “They devour fish and insects, along with the eggs and tadpoles of frogs and toads. So they’ve got to go.”
Over the past year, Troy and her gaggle of volunteers have trapped and removed roughly 44,000 crayfish from streams in the Malibu Creek Watershed - and that is a lot of crayfish. And Troy had all the crayfish they caught sent to the California Wildlife Center in Malibu, where they were used to feed possums and raccoons.
So, how do they catch so may crayfish?
The process involves checking the contents of 400 wire traps set a few yards apart in various locations of the creek bottom. They pull up the traps, count the number of crayfish in each one and empty the catch into plastic buckets. Then they rebait the traps with chicken-flavored dog food and returned them to the river bottom. Troy estimates that on a good day, volunteers can catch up to 600 crayfish in one day.
Tray is getting a lot of support from others in her field as Troy does her part to allow native species to return to the Malibu Watershed.
“I’m proud of what Kyle and her crew are up to out there,” said Lee Katz, a biologist at Pepperdine University who has studied local crayfish populations for two decades. “By removing crayfish, they are allowing precious native species from aquatic insects to newts and steelhead to rebound.”
Katherine Pease, a watershed scientist at the nonprofit Heal the Bay, was more blunt. “These crayfish, which are the same type folks like to eat at Cajun-style crayfish boils, are a huge threat to Southern California’s native aquatic species.”
“As a scientist, I find them somewhat charismatic,” she added with a laugh. “Personally, I do hate them.”
Here is the link to the L. A. Times article:
http://www.latimes.com/...
Here is a link to a video on you tube narrated by Wendy Malick that really gives you a great overview on the Malibu Creek Watershed. It's about 25 minutes long and well worth the time spent watching it:
https://www.youtube.com/...
Here is a link to information on the Malibu Creek Watershed:
http://www.healthebay.org/...
And here is a great link with information about the steelhead trout:
http://www.biologicaldiversity.org/...