After decades of fewer native fish in Grand Traverse Bay, important species like lake trout, whitefish, and lake herring may have a fighting chance to increase their numbers, thanks to a U.S. Environmental Protection Agency Great Lakes Restoration Initiative grant recently awarded to a partnership led by The Nature Conservancy, the Michigan Department of Natural Resources, Central Michigan University, U.S. Geological Survey and Grand Traverse Band of Ottawa and Chippewa Indians.
Scientists from the partnership received a significant grant recently to develop and test techniques to control two kinds of aquatic invasive species in the bay – rusty crayfish and round goby. The two species can be found in large densities on reefs where native fish spawn. The invasives are known to prey on the eggs of native fish, which are critical to the $4 billion Great Lakes fishing industry.
For the past four years, the Michigan Department of Natural Resources and Central Michigan University have collected data on the natural reproduction and survival of native fish that lay their eggs on spawning reefs in Grand Traverse Bay. This preliminary work identified the invasive egg predators as one of the leading factors that limits the spawning success of important native fish species.
“We are trying to give the native species a helping hand,” said Lindsay Chadderton, The Nature Conservancy’s aquatic invasive species director for the Great Lakes. “If this works, it would provide an example of how we can strategically control aquatic invasive fish in key habitats or during periods when native fish are especially vulnerable, like during spawning. That way, we can provide more effective large-scale benefits for native fish species.”
The new grant funding will allow the partnership to implement traditional and innovative tactics to reduce the impacts of the invasive fish species. Traditional trapping methods will be used to catch rusty crayfish and some round gobies. However, since round gobies are more mobile, a new innovative method using pulse pressure technology, or a seismic gun, will be employed.
The USGS is currently evaluating the use of seismic water guns as a control method for Asian carp in the Chicago area waterway system and other invasive fish in south central Alaska. The testing in Grand Traverse Bay against round gobies will begin in the summer of 2012.
“The use of seismic technology for this purpose has never been attempted. We have had success using these technologies as a sound or acoustic barrier, clearing fish from other areas, so the potential to move goby off spawning grounds is an idea worth testing,” said Jackson Gross, a USGS research scientist involved in pioneering these methods. “The low frequency energy from the seismic technology is designed to penetrate the substrate, which is where the round goby are hiding. This is an important area to protect for our fish communities and what we learn here may be applied elsewhere. Hopefully, we will be annoying enough and make those gobies pack up and leave the neighborhood.”
Round goby and rusty crayfish are a pervasive threat across the Great Lakes and scientists say it is highly unlikely that they can ever be eliminated completely from the system. However, tools like these might allow short-term control at selected sites, which could provide wider benefits for native species.
“Since this restoration project emerged from a strong science foundation, we are confident we are addressing one of the most critical threats to these native fish species,” said Tracy Galarowicz, an associate professor at Central Michigan University who has spent the last four years studying native and invasive fish in Grand Traverse Bay. “What we are trying to do here is experimental and innovative, but we believe we can control these invasive species and increase egg survival of these native fish.”
“If we see the response we anticipate, we can apply this at broader scales to more effectively restore native fish populations across the Great Lakes,” said Matt Herbert, an aquatic ecologist for The Nature Conservancy.
Herbert said that aquatic invasive species are not the only factor limiting recovery of these native fish. Many reefs have been impacted by development, including a critical reef off of Elk Rapids that has been severely degraded by past dock construction.
Restoring that reef will require new limestone cobble rocks to be added to the reef to improve protection and cover for native fish eggs. About $300,000 is needed for that part of this integrated restoration project, and the partnership will work together to raise that funding.
“We’re extremely concerned about the status of our native Great Lakes fish like lake trout and whitefish and the ongoing impacts of invasive species and habitat degradation,” said Randy Claramunt, a fishery research biologist for the Michigan Department of Natural Resources. “We’re hopeful this work will help develop new approaches to tackle these problems and rehabilitate a healthy native fish population.”
The partnership will work together over the next three years to implement, monitor and assess progress on the pilot project. They expect this initial phase of the project to be completed by 2015.
“The health of the whitefish population is hugely important to the Native American community which has fished these waters for centuries,” said Erik Olsen, fisheries biologist, of the Grand Traverse Band of Ottawa and Chippewa Indians. “Lake Michigan whitefish are more than just fish; they are part of the Native American heritage and way of life.”
The Michigan Department of Natural Resources is committed to the conservation, protection, management, use and enjoyment of the state's natural and cultural resources for current and future generations. For more information, go to www.michigan.gov/dnr.
USGS provides science for a changing world. For more information, visit www.usgs.gov.
The Nature Conservancy is a leading conservation organization working around the world to protect ecologically important lands and waters for nature and people. The Conservancy and its more than 1 million members have protected nearly 120 million acres worldwide. Visit The Nature Conservancy on the Web at www.nature.org.