Science Advisory Report  2012/051

Recovery potential assessment of Northern Madtom (Noturus stigmosus) in Canada

Summary

• The current Northern Madtom distribution is limited to four distinct locations in Canada: St. Clair River, Lake St. Clair, Thames River and Detroit River.
• One historic location in the Sydenham River is likely extirpated.
• Adults occupy a wide range of habitats with clear to turbid water of large creeks to big rivers, with moderate to swift current, and lakes. Little is known about young-of-the-year and juvenile habitat.
• Northern Madtom occupy residences (cavity nests) during the breeding and rearing parts of its life cycle. Spawning takes place in cavities and males guard the young in the nest until about one month after hatch. Spawning season begins with water temperature at approximately 23°C and nests are occupied for a month post-hatch (June to September) in Canada. It is uncertain when Northern Madtom start building nests.
• To achieve ~97% probability of persistence in 100 years, the Minimum viable populations ranges from 74,000 or 2.7 million adult Northern Madtom with a 5 or 10% chance of catastrophic decline (50%) per generation, respectively. They would require a minimum of 59.7 ha of optimal river habitat or 314.7 ha of suitable lake habitat. Extinction risk is elevated and recovery is delayed exponentially if optimal habitat is less than this. Habitat restrictions result in reduced probabilities of persistence and ability to recover.
• There are insufficient data to determine recovery times however recovery times can be reduced by increasing fecundity rate or survival rate of subadults.
• The greatest threats to the survival and recovery of Northern Madtom in Canada are invasive species and climate change then siltation, nutrient loadings, habitat loss, and increases in turbidity.
• Population growth rate is very sensitive to perturbations of fecundity at any stage and survival of juveniles in the first year.
• There are insufficient data to determine allowable harm. Population trajectories are unknown as are vital rates for Canadian populations. Scientific research to address the lack of population data should be allowed.
• There remain numerous sources of uncertainty related to Northern Madtom biology, ecology, life history, young-of-the-year and juvenile habitat requirements, population abundance estimates, population structure, and species distribution. A thorough understanding of the numerous threats affecting the Northern Madtom populations is also lacking.

This Science Advisory Report is from the March 19, 2012 Recovery Potential Assessment of Northern Madtom (Noturus stigmosus). Additional publications from this process will be posted as they become available on the DFO Science Advisory Schedule.

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