Subfossil Chironomid Assemblages as Indicators of Remedial Efficacy in the Historically Contaminated St. Lawrence River at Cornwall, Ontario.

Long-term data are required to quantify the impacts of historic industrial pollution and subsequent remedial action on the nearshore benthic community in the St. Lawrence River Area of Concern at Cornwall, Ontario. Specifically, high-quality temporal records are needed to understand changes in benthic invertebrate assemblages in response to multiple possible drivers including industrial pollution, environmental heterogeneity, and climate warming.

Nearshore Sedimentary Mercury Concentrations Reflect Legacy Point Sources and Variable Sedimentation Patterns Under a Natural Recovery Strategy.

The St. Lawrence River at Cornwall, Ontario, Canada, received substantial inputs of mercury from local, shoreline-based industries through much of the 20th century. Although emission controls were implemented in the late 20th century to reduce the influx of mercury and other metals entering the river, legacy contamination of riverine sediments continues to be a concern.

Preferential incorporation of dark, coloured materials into nests by a mound-nesting stream cyprinid.

We compared size and colour characteristics of rocks used by male cutlip minnows Exoglossum maxillingua to build nests to those of streambed background materials. We found that materials used to construct conspicuous, mound-shaped nests were uniform in size and darker and more colour-saturated than background materials of the same size. To our knowledge, this phenomenon is the first reported example of fish selecting nest materials based on colour and has important implications for the conservation of mound-nesting stream cyprinid species.