Spotted sucker (Minytrema melanops) COSEWIC assessment and status report: chapter 8
Limiting Factors and Threats
As previously identified by Parker and McKee (1984) and Campbell (1994), there is insufficient data on Canadian populations to be able to identify these factors. It can be assumed that the continued availability of suitable habitat is vital to the survival of the spotted sucker populations. However, a lack of information on the distribution and characteristics of such habitats limits the ability of managers to protect them. Habitat degradation from siltation has been identified as the cause of the decline of some U.S. populations (Trautman 1981). Trautman (1981) interpreted the spotted sucker to be intolerant to turbid waters, industrial pollutants and river beds covered with flocculent clay and silt. Dextrase et al. (2003) considered increased erosion and turbidity the greatest threat to Sydenham River populations. Dams have been widely reported to have negative impacts on catostomid species. Kelly et al. (1981) reported reduced spotted sucker abundance after impoundments were constructed along Shoal Creek, Alabama. Large artificial increases in discharge have also been reported to cause short-term reductions in the local abundance of stream-dwelling spotted sucker populations (Paller et al.1992). It is also likely that water temperature is important in limiting this species as it is at the northern edge of its range (Dextrase et al. 2003). Spotted suckers are only incidentally caught in the Great Lakes basin, usually in trap nets or by hook and line. Specimens captured by commercial fishermen in Ontario are lumped with other rough fish and sold as mullet or used for agricultural purposes.
Inland populations are in an agricultural landscape with attendant issues of nutrient and sediment input. Detroit and St. Clair River populations could be at risk from toxic chemical spills in the chemical valley.
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