Science Advisory Report 2010/058

Recovery Potential Assessment of Channel Darter (Percina copelandi) in Canada

Summary

• In Ontario, the current and historic Channel Darter distribution is limited to four distinct areas of the Great Lakes basin: Lake St. Clair; Lake Erie; Bay of Quinte; and, Ottawa River (Figure 1). Five historic locations are thought to be extirpated: Holiday Beach; Point Pelee; Port Burwell; Rondeau Bay; and, Port Dover. Channel Darter has recently been detected from two new locations: Little Rideau Creek; and, Salmon River.
• In Quebec, the current and historic Channel Darter distribution is limited to 18 distinct watersheds. Current data are available for eight watersheds, while many historic locations have not been recently sampled. Channel Darter has recently been detected in a few new locations: St-Francois; and, Ottawa River system. Many systems with suitable Channel Darter habitat have yet to be sampled.
• In Ontario, Channel Darter is typically found in a variety of habitats, including wave-swept gravel and sand lacustrine beaches, coarse substrate shoals and riffles in large rivers, and riffles and pools of small- and medium-sized rivers. In Quebec, the Channel Darter generally occurs in moderate-flowing rivers or rivulets with waters less than 60 cm deep and gravel substrates composed of a combination of cobble and other types of material. In its known distribution range, habitat variables associated with the presence of the species vary, which seem to indicate that the species adapts well in different types of habitat.
• To achieve a 95% probability of persistence over 250 years, given a 5% chance of catastrophe per generation, a population with 6 800 adults is required. If the chance of catastrophe were 10%, a population with 31 000 adults is needed.
• Under current conditions, and in the absence of recovery efforts, a Channel Darter population at 10% of either of these minimum viable population (MVP) sizes will take 23 years to reach a 95% probability of recovery. Depending on the recovery strategy applied, the time to recovery improved, ranging from 10 to 20 years.
• A population with 6 800 adults requires at least 0.9 ha of suitable habitat. A population with 31 000 adults requires at least 4.1 ha of suitable habitat.
• If eight discrete populations are at, or above, the minimum viable population (MVP), the risk of extinction in Canada is 2.5% over 250 years. If the number of discrete populations at MVP is increased to 10, the risk of extinction in Canada is reduced to 1% over 250 years.
• In Ontario, the greatest threats to the survival and persistence of Channel Darter is related to the introduction of exotic species, shoreline modifications and increases in turbidity and sediment loading. Secondary threats include nutrient loading, altered flow regimes, incidental harvest, contaminants and toxic substances, and barriers to movement. Similar threats are negatively affecting Quebec populations; although, it is noted that threats with the greatest negative effect stem from agricultural activities including turbidity and sediment loading, contaminants and toxic substances, and nutrient loading. Secondary threats include shoreline modifications, and altered flow regimes.
• Channel Darter population dynamics are particularly sensitive to perturbation of annual survival probabilities in the first, second, and third years of life, and the fertility of first- and second-time spawners. Harm to these life history characteristics of Channel Darter should be minimized to avoid jeopardizing the survival and future recovery of Canadian populations.
• There remain numerous sources of uncertainty related to Channel Darter biology, ecology, life history, YOY and juvenile habitat requirements, population abundance estimates, population structure, and species distribution. A thorough understanding of the threats affecting the decline of Channel Darter populations is also lacking. Numerous threats have been identified for Channel Darter populations in Canada, although the severity of these threats is currently unknown.

Complete document (PDF, 209 KB)

Accessibility Notice

This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.