Editor’s note: This is the third in a series of stories on how new technology is giving researchers a glimpse of the critical nearshore area of the Great Lakes.
With researchers hunched over remote controls, operating the Stealth II looks more like playing a video game than doing science.
The Environmental Protection Agency purchased the underwater vehicle in May 2009. Using a hand control, agency scientists can operate the Stealth II as it hovers at various depths of the Great Lakes’ nearshore. The Stealth II’s camera allows scientists to map the bottom of nearshore areas and better understand habitat types.
After some more practice with the equipment, researchers will add the vehicle to their arsenal for studying the Great Lakes, said Glenn Warren, team leader for the agency’s environmental monitoring and indicators group in the Great Lakes National Program Office.
Nearshore Navigators
“They want, and we need, habitat mapping in nearshore — both to look at fish populations and how habitat affects fish populations, and also documenting habitat so we know what areas at the bottom are sensitive,” he said.
The Stealth II will operate in tandem with the Triaxus, a piece of equipment the agency’s research vessel tows behind it. The Triaxus uses sonar and biological and chemical sensors to characterize water conditions. But sonar alone limits what scientists can see and the Triaxus’ coarse resolution is further complicated by an echo that provides false color of what the Triaxus is viewing.
That’s when the Stealth II comes in. Its high resolution black and white video and low resolution color video will be used to document what the habitat looks like, Warren said.
“Once we’ve found structures, rock or whatever’s on the bottom of interest to the habitat folks, we’ll use the Stealth II’s video capabilities to document what’s down there.”
Researchers use the Stealth II’s underwater camera to study aquatic habitat. Photo courtesy of Shark Marine Technologies Inc.
In addition to its camera, the Stealth II has sonar to navigate murky waters and a manipulator arm which can pick up fallen tools from the lake bottom or attach additional hooks and gear to other equipment.
The research could help scientists like Edward Rutherford, a research fishery biologist for the National Oceanic and Atmospheric Association Great Lakes Environmental Research Laboratory.
“Especially in the nearshore zone, fish are oriented to structure and (many) fish spawn on rocky substrates,” Rutherford said.
Once eggs hatch, many young fish swim toward rocky areas on the bottom for protection. Knowing more about the composition of the bottom of Great Lakes in nearshore areas could help with fish population studies, he said.
“That will give us a basis for folks understanding where fish might be using these habitats as well as protecting those habitats from development on land near those areas,” Rutherford said.
Mapping the bottom can also aid scientists’ understanding of how natural events affect fish populations.
“I think this new technology can help us learn a lot more about fishes’ environment because we traditionally have only been able to go out on a particular day or week time frame to sample where fish are,” Rutherford said. “We don’t have a complete understanding of what affects fish in their habitat. So these new technologies will hopefully be able to tell us how much habitat is there as well as sample events like storms or winter periods that really do affect fish that we don’t really know much about.”
Research about the lake bottom could also help with rehabilitation of coastal areas in the Great Lakes, said Jim McKenna, a research ecologist with the U.S. Geological Survey Great Lakes Science Center and Tunison Laboratory of Aquatic Sciences.
“One of the things that sediment is important for is the type of and extent of submerged aquatic vegetation growth,” he said.
Once vegetation growth is mapped based on sediment type, McKenna said they could predict where it might be found. In addition, understanding changes to nearshore areas would help determine which areas could be repaired or restored. Sediment studies would also help researchers understand fish populations present in these areas by matching them to prey types commonly found in the sediment type.
Warren believes work will start this summer. Lake Michigan might be the first to see the Stealth II, though Warren expects the research will eventually include all of the Great Lakes.
Yesterday: Triaxus reveals Great Lakes sunken ships and data treasures
Tomorrow: Lure of good data drives scientists into a buoy arms race
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