Why are zebra mussels harmful invasive animals in the Great Lakes?

Zebra mussels (Dreissena) are considered harmful invasive species in the Great Lakes due to their rapid proliferation and destructive impact on local ecosystems and infrastructure.12

Their presence causes significant harm in several ways:

• Disruption of Food Webs: These mussels are voracious filter feeders that consume large quantities of phytoplankton. By depleting this primary food source, they disrupt the food chain that supports native fish species.12
• Threat to Native Species: Their invasion has driven many native mussel species toward extinction, as they compete for resources and habitat.12
• Commercial and Structural Damage: Zebra mussels adhere in massive clusters to virtually any surface. This behavior causes severe damage to human-made structures, including water-intake valves, pipes, and bridge abutments, leading to significant economic costs.12

Introduced to North America around 1986, likely via ship ballast water, these bivalve mollusks continue to spread to inland waterways, posing an ongoing threat to aquatic biodiversity and infrastructure.12