The city of Lockport, a community of 21,000 residents in upstate New York, relies on the Niagara River for its drinking water. The river connects Lake Erie to Lake Ontario and provides Lockport with more than enough clean water to satisfy demand. But in recent years, millions of invasive mollusks, each the size of a human fingernail, have complicated the task of pumping that water to residents.
The invaders are zebra mussels, named for their characteristic striped shells. This invasive species affixes to nearly any submerged hard surface, from rocks to piers to boats. In the Niagara River, the mussels have encrusted the grate covering the opening to the intake pipe that supplies Lockport with drinking water, reducing the capacity of the pipe. Lockport is currently working to replace the damaged grate at a cost of $800,000.
Zebra mussels are native to freshwater ecosystems in Russia and Ukraine and are thought to have travelled to the United States in the ballast water of ships. Zebra mussels were first discovered in North America in Lake St. Claire near Detroit in the 1980s. Since then, they have spread rapidly throughout waterways in the Great Lakes basin, Mississippi River, and other U.S. watersheds and have been spotted in more than 30 states and Canada.
Thousands of communities like Lockport are now burdened with the costs of the zebra mussels’ presence. These can include damages to boating equipment, dampened tourism, and clogged pipes at power and wastewater treatment plants. In the Great Lakes region, wastewater treatment facilities spend an average of $350,000 annually to monitor and mitigate zebra mussel outbreaks. Individual power plants and industrial facilities in the region spend upwards of $2 million annually to control them.
In addition to causing economic damage, zebra mussels pose a significant environmental threat. They have no natural predators in North America and each female produces roughly five million eggs over the course of her lifespan. This allows zebra mussels to rapidly colonize ecosystems at the expense of native mollusk species. Zebra mussels filter large quantities of plankton from the water column, depriving fish and other aquatic life of a valuable food source. Ecological damage from zebra mussels in the Great Lakes region has negatively impacted the $3.4 billion commercial and recreational fishing sector, which employs more than 10,000 people in the region.
The Great Lakes have a long history of invasive species outbreaks, starting with the introduction of the sea lamprey in Lake Ontario in the 1830s. Since then, at least 180 invasive species, including the round goby, spiny water flea, and a close relative of the zebra mussel, the quagga mussel, have colonized the Great Lakes. The economic and environmental costs incurred by these invasions amount to more than $200 million each year in the Great Lakes region alone. Across the country, the total economic cost of invasive species is $120 billion a year.
The more an invasive species becomes established in an ecosystem, the more money must be spent on regulations, monitoring programs, and eradication measures to prevent severe economic and environmental impacts. Thus, the most cost-effective strategy for curtailing invasive species is prevention. Since 2006, ballast water regulations that require oceangoing vessels to dump their ballast water at sea before entering the St. Lawrence Seaway have helped reduce the risk posed by zebra mussels and other invasive species.
Invasive species can also enter the waters of the Great Lakes in other ways. Asian carp, a large adaptable fish that was accidentally introduced into the Mississippi River watershed in the 1970s, is on the verge of entering the Great Lakes. The U.S. Army Corps of Engineers currently maintains several electric barriers in the Chicago Area Waterway System designed to prevent the spread of Asian carp from the Mississippi River into the Great Lakes. Unfortunately, the carp have circumvented the fence on several occasions. Additional barriers and monitoring efforts will be necessary to limit the spread of Asian carp and other invasive species and ensure the economic and ecological health of the Great Lakes region.
Published in March, 2017, by the Joint Ocean Commission Initiative.