Tiny snail causes big problems for Malibu Creek watershed

Medea basin

TINY TERROR-The New Zealand mud snail, shown here next to a quarter, is less than one-eighth inch in size. Yet the small mollusk can wreak havoc on the native watershed population. The mud snail has been positively identified in Malibu Creek, much to the dismay of local environmentalists. is already under siege

The destructive New Zealand mud snail has been positively identified as living in the Malibu Creek waterCreek watershed, Kim Kratz of Aquatic Bioassay and Consulting Laboratories in Ventura said.

The California Department of Fish and Game verified the finding May 30.

The Ventura lab discovered the snails in samples for the Malibu Creek watershed monitoring program.

The snails are already dominating native invertebrates at Medea Creek in Agoura Hills. Individuals also have been identified in samples from Lower Malibu Creek, just north of the lagoon.

The invasive snails consume algae resulting in declining populations of native bottomdwelling invertebrates such as dragonfly larva. The resulting loss in forage leads to a drop in fish and amphibian populations.

The development is especially troublesome for the Malibu Creek watershed because it is home to two already endangered fish species, the steelhead trout and the tidewater Goby, experts say.

New Zealand mud snails were introduced to North America's Snake and Madison rivers in the 1980s and very quickly colonized Yellowstone National Park. Since then, populations have spread to California, probably by attaching themselves to waders, fishing gear and boats.

Averaging an eighth of an inch in length, the snail ranges in color from gray to brown to black and can survive in most types of water simply by clinging to moist gear.

Densities of more than 750,000 per square meter have been found in Yellowstone National Park waters.

The recommended procedure for preventing the spread of the snails is to freeze equipment exposed to infected waters for six to eight hours.

Mark Abramson of Heal the Bay referred to the finding as "an ecological disaster in the making."

An emergency summit is being proposed to address the situation, but the outlook for the fight against the snail isn't good.

"The way it's been moving around the country you need to have a strong expectation that you are going to have to live with it," said Camm Swift, a renowned fisheries biologist.

Randall Orton, Las Virgenes Municipal Water District resource conservation manager, warned that the snail population could easily spread over Fourth of July weekend.

"If in doubt, stay out," Orton warned those thinking about venturing into Malibu Creek over the holiday weekend.

Orton said that if families do plan on hiking around the creek, they should wash their sneakers with bleach afterwards to prevent the snail from infestating other areas. He also recommended that families don't travel from park to park.

For further information on the New Zealand Mud Snail, visit www.protectyourwaters.net.