Survey of Macrobenthos of the Upper St. Marys River. Field Reconnaissance Report Great Lakes - St. Lawrence Seaway. Navigation Season Extension Program.

摘要

Most recent proposals for the upper Great Lakes would extend the commercial shipping season to January 31 + or - 2 weeks. Adverse environmental effects resulting from navigation season extension, particularly to the narrow connecting waters of the Great Lakes such as the St. Marys River System, are a major concern. Ecological information necessary to evaluate the impacts of navigation season extension have been lacking for the St. Marys River, particularly for the portion above the Soo Locks. Baseline environmental studies were begun in the late 1970's, concentrating mainly on the lower portions of the river. The purpose of this field reconnaissance was to provide qualitative data in an attempt to help characterize the biological communities in this part of the river. Benthic macroinvertebrates of 35 taxa (gross taxonomic categories) were identified from 87 analyzed Ponar grab samples. The taxonomic assemblages and numbers of macrobenthic organisms found to be present in the upper St. Marys River are indicative of a very high quality and productive environment. The rich and diverse benthic community present is capable of supporting many important fish and wildlife resources, particularly fish and migratory waterfowl. Results of this effort support previously expressed concerns regarding environmental impacts to the St. Marys River potentially resulting from the navigation season extension, as well as additional dredging/disposal and operation of longer and/or deeper draft vessels alternatives being considered. (edc)