Population Characteristics and Contaminant Burdens of the White Sucker (Catostomus commersoni) from the St. Lawrence River near Cornwall, Ontario and Massena, New York

The objective of this study was to compare ecological and chemical characteristics of two populations of white sucker (Catostomus commersoni) (n = 762) upstream and downstream of the Moses-Saunders power dam in the St. Lawrence River. The downstream section of the St. Lawrence River near Cornwall, Ontario and Massena, New York is an International Joint Commission Area of Concern (AOC). Population characteristics and contaminants were measured in white suckers caught in 1994 and 1995. Surprisingly, fish collected from the AOC were healthier than fish from the non-AOC. Upstream fish were shorter and lighter at older ages, had a lower average fecundity, lower condition factor when spawning, a greater mean egg diameter, and a greater number of lip and body papillomas than downstream fish. Forty fish from each area were also analyzed to determine mean total concentrations of polycyclic aromatic hydrocarbon compounds (PAHs), polychlorinated biphenyls (PCBs), and several organochlorine pesticides in muscle tissue. Although concentrations of total PAHs were significantly higher in white suckers caught upstream of the dam, no statistical difference in organochlorine contaminant concentration was found between upstream and downstream fish, except for total aldrin. Of the organochlorines analyzed, PCBs, chlorobenzenes, and DDT were present at the highest concentrations in both upstream and downstream fish. A possible reason for the higher PAH levels in upstream fish is that PAHs from the Great Lakes and other upstream sources settle out and become “trapped” in the sediments of the upstream reservoir due to the slow moving water.