INVASIVE SPECIES EDITION—Where we take a moment to explore the species that potentially threaten the Great Lakes region.
Zebra and quagga mussels have already made homes in the Great Lakes region, but there’s another invasive clam on the horizon we should keep our sights on. While still limited to countries in South America, researchers predict that the golden mussel could colonize areas in North America where zebra and quagga mussels could not, devastating what native clam populations remain.
Originally from China, the golden mussel was introduced to Argentina around 1990 by way of ballast water. The microscopic size of its larvae combined with its ability to attach to aquatic plants, ships, and fishing equipment has made its spread difficult to contain. By 2006, the golden mussel had made its way to Brazil, Bolivia, Uruguay, and Paraguay, where they now cost communities an estimated $200,000 a day in industrial and ecological losses.
Like zebra and quagga mussels, golden mussels clog pipes and alter food webs wherever they spread — only the golden mussel takes things a step further. Considered an “ecosystem engineer,” large populations of golden mussels often completely change the biological makeup of a lake’s sediment.
Because they are filter feeders, golden mussels greatly deplete the amount of suspended material in a water column, which in turn depletes the water’s oxygen levels. The end result is an ecosystem that favors detritivores and invertebrates like leeches, caddisflies, and other species that can live in the nooks and crannies golden mussels create, and are able to feed on golden mussel fecal matter. And native clam species stand little chance of survival as golden mussels have been known to surround and grow on top of them, starving them to death by sealing them shut.
As with most invasive species, the success of the golden mussel is rooted in its versatility. A freshwater clam, it can survive in higher temperatures, lower pH levels, and higher salinity than either zebra or quagga mussels. Although no effective method of control has been established, research is being conducted on the potential for sterilization via genetic modification.
Even before zebra and quagga mussels arrived in the Great Lakes in the 1980s, the future looked a little bleak for native mussels. The invaders came close to wiping them out entirely. But small populations in Lake Erie appear to not only be surviving the invasion, but thriving.
Average density of native mussels before the arrival of zebra mussels was two per square meter in Lake St. Clair. By 1990, zebra mussel density was at 1,600 per square meter.
“By 1992, native mussel populations are almost gone from the southeastern portion of the lake and declining rapidly in the northwestern portion of the lake,” said [Dave] Zanatta, [a biologist at Central Michigan University].
By 1994, there were almost no native mussels left in the lake, with zebra now at 3,000+ per square meter.
“But there was reason for hope,” said Zanatta. “Remnant populations of native mussels were beginning to be found in coastal wetlands in western Lake Erie in the late 1990s.”
More recent research funded through the Great Lakes Restoration Initiative also reveals that native mussels have maintained genetic diversity, a key to any species’ long-term survival.
Again from The Voice:
Zanatta’s research adds further evidence that progress continues to be made on one of the impairments of the St. Clair River – the degradation of fish and wildlife habitat – that led to its classification as an environmental Area of Concern in 1985.
His work also sheds light on the complex ecological impacts of invasive species generally.
With some environmental observers predicting a doomsday scenario for native game fish if Asian carp are able to establish themselves in the Great Lakes, for example, Zanatta’s mussel research suggests that the outlook for native fish might be significantly more positive than forecasts suggest.
To read the full article, click on the link above.
**Photo of zebra mussels courtesy of Michigan Sea Grant.
Quagga and Zebra mussels have been a problem for waterways including the Great Lakes for decades, but there may finally be a targeted solution that can significantly reduce their numbers without disrupting other organisms.
“Now the mussels may have met their match: Daniel P. Molloy, an emeritus biologist at the New York State Museum in Albany and a self-described ‘Bronx boy who became fascinated by things living in water.’
Inspired by Rachel Carson’s ‘Silent Spring’ in high school, Dr. Molloy, now 66, has long been a pioneer in the development of environmentally safe control agents to replace broad-spectrum chemical pesticides.
As a result, New York State has awarded a license to Marrone Bio Innovations, a company in Davis, Calif., to develop a commercial formulation of the bacterium. The product, Zequanox, has been undergoing tests for several years, with promising results. (Dr. Molloy has no financial ties to the company.)
Zequanox killed more than 90 percent of the mussels in a test using tanks of water from Lake Carlos in Minnesota, said James A. Luoma, a research biologist with the United States Geological Survey in La Crosse, Wis. A control group of freshwater mussels, unionids from the Black River in Wisconsin, were unharmed.”
Read the rest of the article at the link above.
Quagga and Zebra Mussels are well-known names in the Great Lakes region, as these invasive species have already had an effect on marine wildlife. But both species are prevalent in waterways throughout the United States, and fighting their spread could require a boost from the Federal government.
From USA Today:
“The mussels, natives of Eastern Europe and Western Asia, were transported to the U.S. in the ballast water of trans-Atlantic cargo ships. They first appeared in the Great Lakes in the mid-1980s, and between 2000 and 2010, they cost that region’s water users some $5 billion. The invaders have since crossed the Rocky Mountains, likely hitching a ride on a vacationer’s boat (they can survive for weeks out of water).
Their rapid spread threatens water supplies and energy systems in the West, a region heavily dependent upon hydropower and often gripped by drought. In response, state officials have stepped up boat inspections and cleaning efforts in addition to calling for federal help.”
Read the complete article at the link above for more information about the spread of these invasives and how additional funding could help step up the fight against their spread.
The folks at Wildlife Forever have teamed up with several partners including the North American Fishing Club to produce a series of television programs about aquatic invasive species that are threatening our waters.
Episode three of “Silent Invaders” offers an up-close and informative look at Asian carp, just one of several species that has either taken hold in our waterways or is threatening to spread and cause significant changes to important ecosystems.
You can watch the entire episode online here, as well as episodes providing information about Zebra and Quagga mussels and round Gobies.
The term “food web” is used to describe the intricate relationships between the many different plants, animals, and organisms that can exist in small or large areas. Understanding food webs in specific environmental locations, such as in one or more of the Great Lakes, can help researchers and communities better respond to changes in those delicate systems. Invasive species are just one example of a potential influence that can drastically alter a food web and have substantial impacts on native environments.
On April 3 and 4, 2012, Illinois-Indiana Sea Grant (IISG) and
GLRRIN Lake Michigan partners from Wisconsin Sea Grant(WISG), Michigan Sea Grant, the NOAA Great Lakes Environmental Research Laboratory, the US EPA Great Lakes National Program Office, and the USGS Great Lakes Science Center hosted a research meeting in Ann Arbor, MI. Approximately 60 researchers from federal, state, university, tribal, and non-profit organizations gathered to discuss their current understanding of food webs in Lake Michigan. Food web structure and function can be affected by many variables, including changes in water temperature, water quality, and/or habitat loss. Recent aquatic invaders, including zebra and quagga mussels, have drastically altered the Lake Michigan ecosystem, leaving researchers with new questions about what variables most affect commercial and recreational fishing, bird populations, non-toxic algal blooms, and overall quality of life for humans and animals.
GLRRIN Lake Michigan hosted a similar meeting in 2008, which helped launch the 2010 Lake Michigan Intensive Monitoring Field Year. Findings presented during the 2012 meeting highlight the inherent variability of Lake Michigan, especially in areas that are less than 20 m deep. Researchers also stressed the need to further understand how the lowest levels of the food chain, such as microbes and nutrient cycling, operate. Understanding these basic levels will help create better tools for decision makers like fishery managers or watershed planning committees. A full report on the meeting presentations and discussions will be made available through the GLRRIN Lake Michigan and IISG websites.