Fish assemblages and habitat conditions of the Saint Lawrence River and its Tributaries

Biodiversity measures provide insight into ecological processes like productivity and ecosystem stability, and rare, vulnerable species are a major component of freshwater biodiversity. This data release provides the data used to address multiple ecological questions about fish and habitat conditions throughout a large section of the St. Lawrence River Valley. More than 140,000 fishes of 87 species, including Threatened and Endangered species (T&E), were collected from a total of 1,140 sample sites, covering 278 stream reaches. We identified 50 distinct fish assemblage types differing in species composition, abundance, and/or diversity, but only 13 of those assemblages included a T&E species. The geographic distribution of multimetric disturbance index values showed where combinations of disturbances to fish habitats might affect rare fish species and aquatic communities in the region.