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CARLSBAD FWO: Partners Work to Remove Nonnative Fish to Aid Recovery of Santa Ana Sucker in the Santa Ana River
California-Nevada Offices , April 3, 2014
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Biologists from several local agencies use nets to capture nonnative fish in the Santa Ana River in California.
Biologists from several local agencies use nets to capture nonnative fish in the Santa Ana River in California. - Photo Credit: Photo Credit: USFWS
A largemouth bass proves it has been eating smaller native fish in the Santa Ana River. In this case, the victim was a native arroyo chub.
A largemouth bass proves it has been eating smaller native fish in the Santa Ana River. In this case, the victim was a native arroyo chub. - Photo Credit: USFWS
Santa Ana sucker and arroyo chub inhabit portions of the Santa Ana River in southern California.
Santa Ana sucker and arroyo chub inhabit portions of the Santa Ana River in southern California. - Photo Credit: USFWS

By Jane Hendron

A dedicated group of biologists from numerous agencies descended upon the upper Santa Ana River in February. Their mission? Remove nonnative, warm water fish that compete and prey upon native fish species, including the federally threatened Santa Ana sucker.

Using a method called electrofishing, biologists probed the water and zapped the fish with a mild electrical current. This temporarily stunned the fish making them easier to catch.

Biologists from the U.S. Fish and Wildlife Service, U.S. Forest Service, California Department of Fish and Wildlife, Riverside-Corona Resource Conservation District, San Bernardino Valley Municipal Water District, the San Bernardino Municipal Water Department, and personnel from the City’s Rapid Infiltration/Extraction facility, spent a muddy, sweaty day carefully searching for and removing the nonnative fish.

The Santa Ana sucker is listed under the Endangered Species Act as threatened, meaning the species is likely to become endangered in the foreseeable future throughout all or a significant portion of its range. This native California fish has been affected by significant changes in the hydrology of rivers and streams, construction and operation of dams, and introduced species of fish such as largemouth bass, and catfish which eat the smaller native fish species like the sucker and arroyo chub.

By removing predatory nonnative fish, native fishes have a better chance of successfully reproducing and surviving to adulthood. At day’s end, a total of 2 largemouth bass, 14 black bullhead catfish, and a green sunfish were removed from sucker habitat.

Kai Palenscar, a biologist with the U.S. Fish and Wildlife Service, said they found evidence indicating that nonnative fish are preying on native species as “one of the captured bass expelled a partially digested arroyo chub.”

Removing nonnative predators is one of several actions being undertaken to help conserve and recover the Santa Ana sucker. Other recovery actions being implemented include: conducting research to better understand fish health, distribution, movement, and reproduction; restoration of spawning habitat in tributaries of the Santa Ana River; and removal of giant reed, a highly invasive, nonnative plant found along the Santa Ana River that can significantly alter stream flows and displace native vegetation.

Santa Ana sucker are found in three southern Californian watersheds: the Los Angeles River; the San Gabriel River; and the Santa Ana River.

Another nonnative removal project is being contemplated for fall 2014, after the sucker’s spawning season is over.

Jane Hendron is the public affairs officer at the Carlsbad Fish and Wildlife Office in Carlsbad, California.


video of Santa Ana sucker and arroyo chub
https://www.flickr.com/photos/usfws_pacificsw/13586881494/in/set-72157643320175703
Contact Info: jane hendron, , jane_hendron@fws.gov



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