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.
 

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.” 

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. 

“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. 

 

Leading a team at the museum’s Cambridge Field Research Laboratory in upstate New York, he discovered a bacterium, Pseudomonas fluorescens strain CL145A, that kills the mussels but appears to have little or no effect on other organisms. 

 

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.”

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.”

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.