Science Advisory Report  2012/069

Recovery Potential Assessment of Pugnose Minnow (Opsopoeodus emiliae) in Canada

Summary

• Pugnose Minnow is currently known to occur in two distinct areas of the Great Lakes basin: the Detroit River and Lake St. Clair and its tributaries. Historic Pugnose Minnow records exist for the Thames River and McDougall Drain (a tributary of the Thames River); however, this species has not been recorded from this system since 1968 and 1984, respectively.
• In Canada, adult Pugnose Minnow are most often found in warm, slow moving areas of turbid streams with little to no aquatic vegetation, over silt/clay substrates or slow moving side channels of larger rivers with abundant vegetation. Historically, Pugnose Minnow has been described as preferring clear, slow-moving, heavily vegetated habitat. It is believed that Pugnose Minnow are currently persisting in sub-optimal areas, as preferred habitat may no longer be available. Very little information exists related to Pugnose Minnow juvenile habitat preferences. Spawning is thought to occur from May to June in Canada.
• To achieve ~99% probability of persistence, given a 10% per generation chance of catastrophic decline (50% decline in population), requires ~6.4 million adult Pugnose Minnow and at least 73.2 ha of suitable habitat.
• To achieve ~95% probability of persistence, given a 10% per generation chance of catastrophic decline (50% decline in population), requires ~366,000 adult Pugnose Minnow and at least 4.2 ha of suitable habitat.
• Current available habitat is estimated at 6000 ha. The quality of this habitat is unknown.
• The threats thought to have the largest effect on the survival and persistence of Pugnose Minnow in Canada are related to turbidity and sediment loading, habitat alterations, and nutrient loading. Lesser threats that may be affecting the survival of Pugnose Minnow include altered coastal processes, invasive species, and incidental harvest, although the current knowledge on the level of impact that these threats may have on Pugnose Minnow is very limited.
• Population growth of Pugnose Minnow is most sensitive to changes in the survival of immature individuals or in fecundity. If the population is declining, it is also moderately sensitive to changes in adult survival.
• Current population abundance is unknown. Exact population trajectory is unknown but assumed to be declining.
• Despite concerted efforts to increase our knowledge of Pugnose Minnow in Canada, there are still a number of key sources of uncertainty for this species related to population abundance, distribution and structure, habitat preferences and to the factors limiting their existence, namely, fecundity, mortality, and growth patterns. Parameters for Pugnose Minnow population modeling were based on simulated life-history data and results should be revisited if new data are collected. Other uncertainties include habitat quality, and the frequency of catastrophic decline of Pugnose Minnow.

This Science Advisory Report is from the November 1, 2012 Recovery Potential Assessment of Pugnose Minnow (Opsopoeodus emiliae). Additional publications from this process will be posted as they become available on the DFO Science Advisory Schedule.

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