The Great Lakes’ most unwanted: Characterizing the impacts of the top ten Great Lakes aquatic invasive species

Abstract

Publication: Science Direct

The Laurentian Great Lakes host one of the world’s highest concentrations of aquatic nonindigenous species (ANS), with 188 identified as of 2023. While many are benign, a significant subset has become invasive, causing notable harm to ecosystems, economies, and human well-being. This study identifies and ranks the top ten most impactful invasive species using a quantitative Organism Impact Assessment (OIA) tool developed by the Great Lakes Aquatic Nonindigenous Species Information System (GLANSIS). These rankings account for both environmental and socio-economic impacts across 12 standardized sub-categories.

The top species—led by zebra mussels, quagga mussels, and alewife—demonstrated significant threats including disruption of predator-prey dynamics, competition with native species, infrastructure damage, and degradation of recreation and aesthetics. The OIA tool enables a cross-taxa comparison of invasiveness, improving prioritization of management resources. While the top ten species shared some traits (e.g., Eurasian origin, ballast water introduction), they do not represent the full diversity of Great Lakes ANS. This analysis provides researchers, policymakers, and educators with a data-driven foundation for addressing current and future invasive threats in the region and supports outreach efforts by clearly identifying which species warrant the most attention.