Increased productivity from sewage effluents can enhance species richness locally. Results from a study of Spottail shiners (Notropis hudsonius) in 1999 showed that prevalence and the mean number of myxozoan parasite species per host were higher downstream of the wastewater outflow from the Island of Montreal than upstream in the St. Lawrence River, Quebec, Canada. This was attributed to organic enrichment of the sediments which presumably lead to increased densities of oligochaetes, the alternate hosts, downstream of Montreal. Spottail shiners subsequently were collected every August/early September in 2001–2004 to examine the stability and repeatability of these patterns. Results suggest that on a local scale, variations in prevalence and diversity among localities are influenced by municipal effluents, but that at a landscape scale annual variations across sites are affected by the hydrological regime and climate. In effect, water level fluctuation had a landscape-wide impact that was superimposed over pollution-induced local variations.
Supplemental Information
The St. Lawrence Action Plan (SLAP) 2011 to 2026 (see http://planstlaurent.qc.ca/en/home.html) is the latest Canada-Quebec Agreement on the St. Lawrence and builds on the four previous agreements implemented since 1988.
The agreement aims to conserve and enhance the St. Lawrence. It is based on strong collaboration and the pooling of resources and expertise between the governments of Canada and Quebec. As part of their respective responsibilities for the management of the St. Lawrence basin, these two governments recognize the need for close cooperation to tackle the environmental challenges facing this important ecosystem. Other partners are also joining in this initiative, including local organizations, environmental groups, research centres, and universities.
For more information on SLAP, please visit https://www.canada.ca/en/environment-climate-change/services/environmental-funding/ecosystem-initiatives/st-lawrence-action-plan.html