Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study shows hope for ridding lakes of clawed invader

02.08.2006
The rusty crayfish - a voracious, bullying exotic that has visited ecological havoc on numerous Wisconsin lakes - may have finally met its match.

Since its introduction to Wisconsin waters sometime in the 1950s, the crayfish has spread to thousands of lakes and streams, clear cutting the underwater forests that are critical fish habitat, evicting the native crayfish from one body of water after another and scooping up fish eggs like so much caviar.

But the clawed invader, the early results of a long-term University of Wisconsin-Madison study suggest, may be vulnerable to a "double whammy" of intensive trapping and predator fish manipulation to the point where it may actually be possible to rid lakes of an animal that has vexed scientists, anglers and conservation agencies alike for decades.

"They pretty much wipe out all of the rooted aquatic plants, they eat fish eggs, they either eat or compete with native invertebrates and, in general, raise havoc with the near-shore community of a lake," says Stephen Carpenter, a UW-Madison professor of limnology and zoology involved in the study on Sparkling Lake in Vilas County, Wis.

Supported by the National Science Foundation (NSF), the long-term study of the feasibility of evicting the rusty from the 110-acre lake is now in its sixth year. It holds the promise of a rare victory in the war against introduced invasive species.

Since 2001, the UW-Madison researchers, aided by a small army of undergraduate students and the Wisconsin Department of Natural Resources (DNR), has succeeded in significantly reducing the population of rusty crayfish in Sparkling Lake through a program of intensive trapping and manipulating fishing regulations to favor the smallmouth and rock bass that dine on juvenile crayfish. The two-pronged attack, says Carpenter, has yielded very promising results.

"It seems to be working. The aquatic plants are back. That's good because that's fish habitat, and the fish populations are returning to what they were before the rusty got into the lake sometime in the 1980s," says Carpenter.

The two-pronged approach to ridding Sparkling Lake of its rusty crayfish is the key, notes Jake Vander Zanden, a UW-Madison professor of limnology who is helping oversee the experiment. "One important message is that trapping alone will not do it. There's a synergistic effect with the fish playing an important role."

Smallmouth bass and rock bass, says Vander Zanden, are the primary predators of juvenile crayfish, and to some degree sunfish - bluegills and pumpkinseeds - pitch in by eating the smallest crayfish. The Wisconsin DNR, by manipulating the bag and size limits for anglers fishing Sparkling Lake, has helped establish an optimal population of the fish that routinely dine on the crayfish.

The trapping on Sparkling Lake, however, has been intensive during six years with 280 traps seeded around the lake. Baited with beef liver, the traps snare both native and rusty crayfish, but the natives, Carpenter explains, are returned to the lake. The trapping targets the largest crayfish, those that may be too big for the lake's predators.

The big hope, says Carpenter, is that the experiment will expose a "tipping point," where the combination of trapping and pressure from predator fish pushes the rusty crayfish population to crash, with the lake ecosystem returning to its pre-rusty crayfish state.

"What we are wondering is whether we will reach a tipping point where the fish alone can keep up the pressure," says Carpenter, an authority on such ecological change. "We haven't seen it yet, but we're not prepared to admit there isn't a tipping point."

Vander Zanden says the rusty crayfish infestation in Sparkling Lake, like most lakes where it is found, was probably sparked by a small pioneer group that somehow got into the lake. At one time, rusty crayfish were used as bait. Misguided attempts years ago to establish the rusty in Wisconsin for commercial purposes also contributed to the spread of the exotic species to 50 percent of Wisconsin lakes and streams.

The practical upshot of the experiment and the real hope, say Vander Zanden and Carpenter, is that the experimental techniques used on Sparkling Lake can be transferred to other lakes with the help of the many lake associations in Wisconsin. The Wisconsin scientists have addressed lake associations and found a receptive audience.

"We have talked to lake associations," says Carpenter. "If everyone was willing to run half a dozen traps off their dock, it could be very effective."

And one of the best parts of the study, according to the Wisconsin scientists, is that the rusty crayfish is edible. "The students up at our Trout Lake Research Station have been eating a lot of crayfish," says Carpenter.

Stephen Carpenter | EurekAlert!
Further information:
http://www.wisc.edu

More articles from Ecology, The Environment and Conservation:

nachricht Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University

nachricht Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Antarctic landscape insights keep ice loss forecasts on the radar

20.11.2017 | Earth Sciences

Filling the gap: High-latitude volcanic eruptions also have global impact

20.11.2017 | Earth Sciences

Water world

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>