Evaluating wild freshwater bivalves as alternative sentinel species in Canadian Environmental Effects Monitoring (EEM)

Abstract

The Canadian Environmental Effects Monitoring (EEM) program assesses whether mines in compliance with effluent regulations are associated with environmental impacts to fish populations, fish habitat, and fisheries resources. The EEM’s fish population survey assesses indicators of survival (age), energy use (growth and gonad size), and energy storage (condition and liver size) using at least two sentinel species collected from a minimum of one exposure area and one reference area for statistical comparison. If a standard fish population survey is not feasible, proponents are required to implement a recognized alternative survey methodology that will produce data on the required endpoints. The McClean Lake Operation in Saskatchewan completed an assessment of wild bivalve populations (Sphaeriidae) as an alternative to the conventional fish population survey for its Phase 6 EEM program. The purpose of this paper is to describe the novel methods and results associated with this wild bivalve survey. Two species of fingernail clam (Sphaerium nitidum, Pisidium casertanum) were collected with minimal effort (2 days’ effort) from both the reference and exposure areas in sufficient numbers for statistical robustness. Measures of survival, energy use, and energy storage were derived from the collections. Those data were deemed by the regulating agencies to meet the requirements of the EEM program under Canada’s Metal and Diamond Mining Effluent Regulation (MDMER). Laboratory analysis required specialized equipment including a microbalance that could weigh to 1 µg and a muffle furnace. The effort associated with the viable alternative method was similar to that of a conventional adult fish population survey.