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Robot boats fight invasive carp

Billy Mull, a commercial fisherman from Grand Rivers, Ky., unloads Asian carp from his boat during a fishing tournament that was organized to remove the fast-breeding fish from two western Kentucky lakes on March 13, 2013 in Gilbertsville, Ky. Oregon also has problems with the invasive species.

Billy Mull, a commercial fisherman from Grand Rivers, Ky., unloads Asian carp from his boat during a fishing tournament that was organized to remove the fast-breeding fish from two western Kentucky lakes on March 13, 2013 in Gilbertsville, Ky. Oregon also has problems with the invasive species. AP Photo/Dylan Lovan

BURNS (AP) — Robot boats are set to sail this summer on Malheur Lake.

But the high-tech tools won’t be used right away to find the non-native carp infesting the lake, as refuge managers had hoped. The summertime study will be more about field testing the boats than searching for the fish, said Peter Sorensen, a professor at the University of Minnesota.

The experimental, 6-foot-long robotic crafts that resemble toy boats are being tested in smaller lakes around Minnesota. Before they launch the craft on Malheur Lake near Burns, Ore., Sorensen said researchers are perfecting the design in the $2.2 million study funded by the National Science Foundation.

“Malheur is kind of our dream,” he said. “It’s like sending a rocket to the moon.”

At the Malheur National Wildlife Refuge, Linda Beck, a fish biologist, dreams of a solution for the million-plus carp crowding the lake. Last year she hoped the University of Minnesota robot boat project would make carp removal a reality, by providing an efficient and effective method of finding where the fish congregate in the lake.

Either landowners or the government introduced carp to the Silvies River in the 1920s in an effort to control vegetation in the river. The carp didn’t eat the targeted plants and eventually infested Malheur Lake. The Silvies River merges with the lake in high water years, about once every seven years.

Poisoning the lake has not proved a lasting solution for the carp situation, Beck said. Since 1955, refuge managers have poisoned the lake five times with rotenone, only to have the fish return.

“We are probably not going to try that again because it didn’t work,” Beck said.

The non-native fish have thrown off the balance of the Malheur Lake ecosystem. The refuge once bustled with birds, but no longer. The carp muddle along the lake bottom, searching for plants and insects to eat. As they do so, they cloud the water with mud, blocking out light from reaching aquatic plants and decreasing the amount of food once available for birds.

There are likely about 1.2 million carp in the lake, Beck has estimated, about three dozen of which are carrying radio transmitters. While refuge workers are trying to use those to determine where the fish congregate, the fieldwork is time- consuming and tedious.

That’s where the robot boats, as well as wheeled models designed to roll over frozen lakes, may eventually prove useful at the refuge. The robots would be programmed to systematically cover the lake and find the carp carrying radio transmitters. Once refuge workers know where the carp gather, they would be able to catch and remove the fish.

Building a robot boat that can find fish is proving to be a challenge.

The receiver used to track transmitter-bearing fish is designed to be used by people, and computers thus far have been unable to differentiate the tones as well as a human, said Volkan Isler, another professor at the University of Minnesota, in an email. The motors on the boats haven’t helped, causing interference that disrupts the sound quality. Researchers from Johns Hopkins University and Central State University in Ohio are also involved in the project.

The robot boats were originally going to be on Malheur Lake this spring, Beck said, but a graduate student quit the project, adding to the boat-design delay.

Beck is still excited about the possibility of robot boats someday helping clear carp from the lake, but for now she’s developing a management plan for the lake that could include other options. Those include establishing a commercial fishery for carp at the lake and working with private landowners to screen off canals in the Silvies River system to keep carp from swimming into the lake.

“We are looking for innovative ways to rid the carp without harming the other fish,” she said.


Information from: The Bulletin, http://www.bendbulletin.com

Copyright 2013 The Associated Press.

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