Tiny Quagga Mussels Have Big Impact on Lake Michigan . . . And Perhaps Climate Change

July 17, 2017

By Marie Zhuikov

As prior researchers have demonstrated, Wisconsin Sea Grant researchers further confirm that the tiny quagga mussel has an outsize impact on Lake Michigan. What’s novel about the study team’s work is the exploration of the age-old biological truth: what goes in must come out. They found the invasive mussels’ sheer numbers and feeding efficiency are changing the lake’s ecosystem dynamics. Perhaps the climate, as well.

Laodong Guo and his graduate student Stephen DeVilbiss, researchers at the University of Wisconsin-Milwaukee, looked at the impacts of quagga mussels from an aquatic chemist’s point of view in a paper published this year in the Journal of Great Lakes Research. They took measurements in Lake Michigan and collected mussels from the lake. They brought the mussels into the lab to assess filtration and excretion rates, and the type of things excreted to better understand their role in the lake’s carbon cycle.

The researchers found that the mussels are highly efficient; each one can filter up to 578 gallons of water every year, with younger, smaller mussels pumping more efficiently. In addition to feces, the mussels excrete dissolved nitrogen and phosphorus, and they “breathe” out carbon dioxide into the water -- so much carbon dioxide, in fact, that it could impact the climate.

“There are so many mussels that the carbon dioxide they release into the water, which gets into the air, may add to the problem of global warming,” Guo said. “Normally, in places like the ocean environment, the water absorbs carbon dioxide. However, Lake Michigan is somewhat oversaturated with carbon dioxide because of the quagga mussels. We need to look at whether this is causing acidification in the lake.”

Estimates of the number of quagga mussels in Lake Michigan by NOAA researchers range from 750 to 950 trillion. More information about how quagga mussels are impacting carbon dioxide dynamics in Lake Michigan and other Great Lakes can be found in a paper Guo and his postdoc, Peng Lin, published last year in Nature’s Scientific Reports.

Another impact the researchers found from their field studies is that quagga mussels are changing the way phosphorous is cycled in the lake. Normally, the amount of phosphorous, a vital nutrient needed for diatoms and other species important in the food web, rises during the winter when it is released from particulate matter resuspended from coastal sediment during storm events and turbulence. The sediment then gets transported from shallow areas to deeper regions in the lake.

“Because quagga mussels carpet the bottom of the lake, the resuspension of phosphorus during winter and during storms is less than it used to be,” Guo said. “When we compare data from

before and after the invasion of the quagga mussels, we find there’s only about one third to less than half of the amount of total phosphorus present in the winter water column.”

Guo thinks these findings will be useful for fishery and environmental managers and Great Lakes researchers. He plans further investigations into how the mussels are impacting the lake’s nutrient and carbon cycling. “It’s kind of unbelievable how the vast numbers of tiny quagga mussels are changing Lake Michigan,” Guo said.

Stalking a Fish Virus

Wisconsin Sea Grant research team tracks the location of the deadly viral hemorrhagic septicemia virus.

July 14, 2017

By Aaron R. Conklin

First, they developed the test. Now they’re using it to track a stealthy, fish-killing virus.

In 2013, Tony Goldberg, a UW-Madison professor of epidemiology, and Kathy Toohey-Kurth, a virologist at the Wisconsin Veterinary Diagnostic Laboratory, used funding from Wisconsin Sea Grant to lead a team that created a quick and accurate test for viral hemorrhagic septicemia virus (VHSV), a deadly disease that attacks the internal organs of fish, leading to bloody and large-scale fish kills. Over the past year—again with support from Wisconsin Sea Grant--Goldberg and his research team have ventured into the rivers and streams of Wisconsin, from the Apostle Islands to Janesville and the Wisconsin-Illinois border, working with the Wisconsin Department of Natural Resources to collecting fish samples to test and track the virus’s current locations and movement among fish populations.

The goal? Developing an effective management strategy to contain VHSV.

“If we catch wildlife diseases early, there’s a lot we can do about them,” said Goldberg. “There’s a window where you can intervene and be adaptive and smart and prevent or even get rid of some diseases with really careful management. VHSV will not be the last fish disease to plague Wisconsin. If we do this exercise and are effective with it, we have a test case, an action plan for the future.”

Taking steps toward that plan has involved a substantial amount of fish sampling and laboratory work. Last fall, Goldberg’s team collected samples from several thousand fish across most of Wisconsin’s major geologic zones.  Whitney Thiel, a graduate student in UW-Madison’s freshwater and marine sciences program, has spent the intervening months performing enzyme-linked immunosorbent assay (ELISA) tests on the scores of fish samples, generating data on the fishes’ antibody levels, which rise in response to an exposure to diseases like VHSV.

The data will help the team solve the project’s biggest mystery—finding the specific cutoff point between negative (never exposed to VHSV) and positive (exposed to VHSV) fish.

“This test has never been applied to many of these fish species before,” explained Goldberg.  “Once we’re able to say what proportion of fish in a lake are serologically positive or negative, that will tell us where in Wisconsin fish have an immunity to the virus.”

That’s critically important information to have, particularly for fisheries managers. VHSV is particularly insidious. Past research (including Goldberg’s) indicates that it can lie dormant in fish population for years, a lurking threat in the absence of visible fish kills. Goldberg studied freshwater drum in Lake Winnebago, using the test his team developed to discover that the fish were maintaining the virus at low levels.

“We know from experience that if you have a naïve population and expose them to the virus for the first time, it’s bad--you get fish kills,” explained Goldberg.  “If we have areas where there are a lot of positive fish, we would want to make sure we didn’t move fish out of there into other areas. If we know our fish hatcheries are free of the virus, we might want to stock fish preferentially into lakes that don’t have the virus so they don’t all die and we don’t waste our money.”

Researchers still don’t know how VHSV manages to persist within lakes. Several possible explanations exist, including the fish shedding the virus during spawning. One of Goldberg’s colleagues at Michigan State University, Mohamed Faisal, recently conducted a study that suggested the virus may be associated with Diporeia, the microscopic Great Lakes zooplankton that historically served as a primary food source for multiple fish species.

“We have a virus that wasn’t here before, and it’s pretty clear it kills fish,” Goldberg said. “So what do you do about it? You have to know where it is. If we just close our eyes and choose not to know where the virus is, it’s just going to spread. We need to set management zones, we need to know which fish to move, we need to educate the public.”

Thiel still has several more months of sample testing to complete before a clearer picture of VHSV in Wisconsin can emerge. In the coming weeks, the research will be taking samples from infected fish to  better understand how their immune systems respond to it.

“Honestly, at this early stage, I would not be surprised by any result,” said Goldberg of the ongoing study. “The only thing I’m pretty confident in is that we’re going to find positive fish where we have found them before.”

Bipartisan Group of Senators Introduce the Modern Fish Act

Recreational Fishermen Laud Wicker, Nelson and Colleagues July 10, 2017 (Washington, DC) - Today, the recreational fishing and boating community praised the Senate introduction of the Modern Fish Act by Senators Roger Wicker (R-Miss.), Bill Nelson (D-Fla.), Roy Blunt (R-Mo.), Brian Schatz (D-Hawaii), John Kennedy (R-La.) and Joe Manchin (D-W.Va.). The "Modernizing Recreational Fisheries Management Act of 2017" (Modern Fish Act) would improve public access to America's federal waters, promote conservation of our natural marine resources and spur economic growth. A companion bill, H.R. 2023, was introduced in the U.S. House of Representatives on April 6, by Congressmen Garret Graves (R-La.), Gene Green (D-Texas), Daniel Webster (R-Fla.) and Rob Wittman (R-Va.). "On behalf of America's 11 million saltwater anglers, we thank Senators Wicker, Nelson, Blunt, Schatz, Kennedy and Manchin for their leadership and commitment to modernizing federal recreational fishing management," said Jeff Angers, president of the Center for Sportfishing Policy. "Recreational fishing is a tradition worth safeguarding through proper management policies and a critical component of the U.S. economy, with an annual economic contribution of $63+ billion. With a bipartisan bill introduced in both chambers, we are hopeful the Congress will ensure all Americans have fair and reasonable access to our nation's marine resources by passing the Modern Fish Act." For years, the recreational fishing community has been hindered by antiquated policies that restrict access to public waters, hurt the U.S. economy and detract from conservation goals. The Modern Fish Act addresses many of the challenges faced by recreational anglers, including allowing alternative management tools for recreational fishing, reexamining fisheries allocations, smartly rebuilding fish stocks and improving recreational data collection. The bill aims to benefit fishing access and conservation by incorporating modern management approaches, science and technology to guide decision-making. "We applaud Senators Wicker, Nelson, Blunt, Schatz, Kennedy and Manchin for working across the aisle to introduce the Modern Fish Act in the Senate. When passed, this landmark legislation will modernize the federal regulations governing access to the public's natural resources by boaters and anglers," said National Marine Manufacturers Association President Thom Dammrich. "We appreciate the commitment of Senators Wicker, Nelson, Blunt, Schatz, Kennedy and Manchin to finding solutions that allow for better management of our recreational fisheries and bring federal management into the 21st century." "The Modern Fish Act will achieve many goals, the most important of which is getting more Americans outdoors and enjoying our wonderful natural treasures," said Mike Nussman, president of the American Sportfishing Association. "This bipartisan legislation includes key provisions that will adapt federal fisheries management to manage recreational fishing in a way that better achieves conservation and public access goals. Recreational fishing provides many economic, social and conservation benefits to the nation, and with this legislation, the federal fisheries management system will better realize those benefits." "The Magnuson Stevens Act is designed to be reviewed regularly because the management needs of our nation's fisheries are constantly evolving. Since the last reauthorization, it has become abundantly clear that the law needs to be revised to provide quality angling opportunities for all stakeholders," said Patrick Murray, president of Coastal Conservation Association. "This legislation signifies that our elected officials on both sides of the aisle recognize the unique needs of the recreational angling sector and the changing nature of fisheries management. We commend Senators Wicker, Nelson, Blunt, Schatz, Kennedy and Manchin for providing a pathway that provides for proper conservation and better management of our marine resources in the future." "The Modern Fish Act offers reasonable solutions to a management system designed primarily for commercial fisheries but which has failed to address the needs of millions of saltwater anglers," said Congressional Sportsmen's Foundation President Jeff Crane. "The simple adjustments in this bipartisan bill would continue to ensure conservation of our nation's saltwater fisheries, while finally establishing greatly needed parity for the recreational fishing community." "The Modern Fish Act would fix key issues in the law governing marine fisheries that keep recreational anglers from enjoying access to healthy fisheries," said Jim Donofrio, executive director of the Recreational Fishing Alliance. The coalition of groups supporting the Modern Fish Act includes American Sportfishing Association, Center for Sportfishing Policy, Coastal Conservation Association, Congressional Sportsmen's Foundation, Guy Harvey Ocean Foundation, International Game Fish Association, National Marine Manufacturers Association, Recreational Fishing Alliance, The Billfish Foundation and Theodore Roosevelt Conservation Partnership.

HELP NEEDED!

Help Needed July 29th/rain date July 30th

The Hunger Task Force is requesting our help again this year at the Brew City Fish Tournament hosted by Great Lakes Sport Fishing Club at McKinley Marina on Lake Michigan at: 1750 N Lincoln Memorial Drive, Milwaukee, WI 53202.

Through the generosity of tournament attendees that may choose to donate their catch to the HTF, we are able to process the fish and distribute cleaned filets to the community.

This is a great community outreach program servicing those less fortunate that would not have the funds to purchase salmon & trout in the marketplace. 

As a possible added bonus, we might even end up encouraging recipients to become anglers and fish on their own!

How can you help? Volunteers are needed at the fish cleaning area from about 12 pm – 4 pm.

Please note that not all volunteers need to know how to clean fish. We also need volunteers to bring the fish to cleaners and also volunteers to put the cleaned filets into zip lock bags and into the refrigerated truck. 

For more information or to volunteer to help, contact us at: wildcatcreekfarm@gmail.com