Channel darter (Percina copelandi) COSEWIC assessment and status report: chapter 8

Limiting Factors and Threats

Channel darters are threatened by the loss of suitable habitat because they are sensitive to sedimentation and decreased water quality. Sedimentation caused by agricultural or urban development affects the survival of the channel darter. Lapointe (1997) described the six rivers in Quebec where biologists failed to capture channel darters as areas that had undergone habitat changes such as agricultural and urban development causing increased sedimentation. In Ontario, dams are an important threat to this species (Alan Dextrase, Ontario Ministry of Natural Resources (OMNR), personal communication). Dams alter flow, flood habitats, cause erosion, fragment populations and restrict access to spawning areas.

Other threats to the survival of Percina copelandi include the disruption of spawning activities. Any activity that impedes or slows water flow during spawning stops their spawning activities. Barriers blocking access to spawning areas also compromise the spawning success of this species. Areas of suitable spawning habitat are diminishing due to naturally occurring and human induced flow modifications and increased suspended sediment.

The round goby, Neogobius melanostomus, may also be a threat to the survival of channel darter in Ontario. The round goby was introduced into the St. Clair River in the mid-1980s from ship ballast water and has since become established in the Great Lakes area. The round goby is tolerant of a wide range of habitat conditions and likely competes with the channel darter for resources. The effect of the goby on channel darters is difficult to estimate although channel darter continue to inhabit the St. Clair River as 65 specimens of channel darter were captured there in 1996.

A tolerance for only a narrow range of habitat characteristics and a limited amount of suitable habitat restrict the population size and distribution of the channel darter. Percina copelandi is at the northern limit of its distribution in Canada with low species numbers and disjunct distributions. All of these factors threaten the continued survival of the channel darter in Canada. 

Page details

Date modified: