Science Advisory Report  2015/009

Review of the Information for the Identification of Critical Habitat for Morrison Creek Lamprey

Summary

• Morrison Creek lamprey was listed in 2003 as Endangered under the Species at Risk Act (SARA), and a Recovery Strategy for the species was completed in 2007 (National Recovery Team for Morrison Creek Lamprey 2007). A variety of factors threaten the Morrison Creek lamprey and its associated habitat. The primary threat is impacts associated with urbanization of the watershed.
• Lampretra richardsoni var. marifuga (Morrison Creek lamprey) has only been identified in the Morrison Creek watershed.
• The Morrison Creek lamprey is a variety of the widely distribution Western Brook lamprey (L. richardsoni). The two varieties can only be distinguished from each other after metamorphosis. Therefore, Critical Habitat must include areas that support all lamprey found in Morrison Creek.
• No quantitative population estimates exist for either variety of lamprey in Morrison Creek. However, catch studies indicate a general decline in numbers over the past 30 years.
• Habitat requirements vary depending on the life stage of lamprey and include regions of free-running fresh water in both main and side channels for adults, slow moving regions with small pebbles and gravel for nests and spawning, and loose silt or sand substrate suitable for burrowing ammocoetes.
• During spawning the nests built by the lamprey within the Morrison Creek watershed would be considered residences as they are discrete dwelling places, adults of both sexes invest energy physically moving pebbles with their oral discs to create the nests, the nests support the life-cycle process of spawning and egg incubation, and the nests are occupied by multiple individuals.
• The primary activities likely to threaten Morrison Creek lamprey are those that harm or destroy their Critical Habitat.  These include, but are not limited to: land-based activities that directly or indirectly alter their aquatic habitat including forestry, mining, and land development; alteration of stream bed composition to benefit other species, including salmon; water withdrawals or impoundments that alter the natural variability in water flow; releases of deleterious substances into the watershed; riparian vegetation removal; and, activities that result in significant sediment inputs.
• The hydrology of Morrison Creek is poorly understood.  Although the wetland area at the headwaters of the creek is vital to the continued source of cool water, the source of water supplying this area has not been identified. It is recommended that a hydrology study be undertaken to understand the relationship between the water sources and discharges from the system.
• The high uncertainty of a number of factors related to Morrison Creek lamprey make the identification of Critical Habitat difficult.  These factors include, but are not limited to: the type and abundance of prey required, the type of vegetation required to maintain the functions of the riparian zone, and the location of spawning sites with the creek. Therefore, further work is suggested to provide quantitative thresholds for Critical Habitat attributes.
• It is recommended that the entire wetted area, channel, and headwaters of Morrison Creek be considered Critical Habitat for the Morrison Creek lamprey.

This Science Advisory Report is from the October 29, 2013 Review of the Information for the Identification of Critical Habitat for Morrison Creek Lamprey. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

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