Science Advisory Report  2011/020

Recovery Potential Assessment of Eastern Sand Darter (Ammocrypta pellucida) in Canada

Summary

• In Ontario, the current and historic Eastern Sand Darter distribution is limited to three distinct areas of the Great Lakes basin: Lake Huron; Lake Erie; and, Lake St. Clair (Figure 1). Four historic locations are thought to be extirpated: Ausable River; Catfish Creek; Big Otter Creek; and, the western basin of Lake Erie. Current records exist from six sites: Lake St. Clair; Thames River; Sydenham River; Rondeau Bay; Big Creek; and, Grand River.
• In Quebec, the distribution of the Eastern Sand Darter is primarily concentrated in the St. Lawrence River and in its tributaries between Deux Montagnes Lake and Leclercville, downstream from Lake St. Pierre. In the St. Lawrence River, some specimens were recently collected in Lake St. Pierre as well as in a reach between Montreal and Sorel. The species has also been recorded in a few tributaries of six regions of the province: Montreal, Laval, Montérégie, Mauricie, Centre du Québec and Lanaudière.
• Eastern Sand Darter inhabit streams, rivers and sandy shoals in lakes in areas dominated by sandy substrate. Eastern Sand Darter have a very strong association to sand substrates, although they have been collected over various substrate types. In rivers, they are generally associated with depositional areas downstream of bends in the river and have also been associated with increased levels of dissolved oxygen.  In lacustrine systems, Eastern Sand Darter were found in the nearshore on sand substrate, and are typically associated with wave-protected, sand beaches.
• In the absence of catastrophic events, the minimum viable population (MVP) size is predicted to be 323 adults. Inclusion of a 0.05, 0.10 and 0.15 probability of catastrophic decline per generation produced MVP values of 4 224, 52 822 and 595 000 respectively.
• Under current conditions, and in the absence of both, human threats and recovery efforts, a population that is 10% of these MVP values is expected to take 45 years to reach the recovery target. Depending on the recovery strategy applied and initial population size, the time to recovery varied from 14 to 50 years.
• A riverine population with 4224 adults would require at least 0.3 ha of suitable habitat, while 595 000 adults would require 41.7 ha. Lake values range from 1.72 – 240.57 ha based on the catastrophic probabilities.
• If eight discrete populations are at, or above, the minimum viable population (MVP), the risk of extinction in Canada is 5%. The risk of extinction will decrease to 2.5% with 10 recovered populations, 1% with 13 recovered populations, and 0.01% with 24 recovered populations.
• In Ontario, the greatest threats to the survival and persistence of Eastern Sand Darter is related to turbidity and sediment loading, contaminants and toxic substances, altered flow regimes and the introduction of exotic species and disease. Secondary threats include nutrient loading, barrier to movement, shoreline modifications and incidental harvest. Similar threats are negatively affecting Quebec populations; although, it is noted that Quebec populations are also facing negative effects from wave action from boats.
• Eastern Sand Darter population dynamics are particularly sensitive to perturbations affecting 0+ survival and the fertility of 1+ spawners. Harm to these life stages should be minimized to avoid jeopardizing the survival and recovery of Canadian populations.
• There remain numerous sources of uncertainty related to Eastern Sand 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 Eastern Sand Darter populations is also lacking. Numerous threats have been identified for Eastern Sand Darter populations in Canada, although the severity of these threats is currently unknown.

This Science Advisory Report has resulted from a Fisheries and Oceans Canada, Canadian Science Advisory Secretariat, Zonal Advisory Meeting of December 2-3, 2009 on Recovery Potential Assessment (RPA) for Eastern Sand Darter. Additional publications from this process will be posted as they become available on the DFO Science Advisory Schedule.

Complete document (PDF, 177 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.