Northern brook lamprey (Ichthyomyzon fossor) COSEWIC assessment and status report: chapter 5

Habitat

Habitat requirements

Rocky or gravel substrate with swift-flowing water is the preferred spawning area for northern brook lamprey. They require a small amount of silt-free sand or some other fine material to which the eggs can adhere, uni-directional current, and suitable water temperatures (Manion and Hanson 1980). Nests have been found in interstices beneath large stones (18 to 36 cm in diameter) (Lanteigne 1991), usually in gravel shallows just above riffles (Hankinson 1932). Larval northern brook lamprey are usually found in depositional areas with soft silt and sand substrate.

Northern brook lamprey are reported to occur in a large range of stream sizes, as authors have claimed they are found in small rivers (Vladykov 1949); small to moderate streams (Scott and Crossman 1973); and moderate-sized to large streams (Morman 1979). According to Becker (1983), it generally occurs in larger stream than the American brook lamprey and in smaller streams than the parasitic silver lamprey. The average width and depth of streams inhabited by northern brook lamprey was documented by Becker (1983) to be 19 m wide and 0.7 m deep. Schuldt and Goold (1980) found northern brook lamprey most common in streams with summer flows of 0.3 to 28.3 cubic metres per second (cms). More recent Canadian stream data show a wide range in mean summer discharges of the stream systems within which northern brook lamprey reside, ranging from 0.17 to 70.99 cms, with an average value of 12.2 cms (SLCC, unpublished data). The average alkalinity of the streams was 91.55 mg/l CaCO3, with a range of 5.86 to 221.00 mg/l CaCO3 (SLCC, unpublished data).

No literature has dealt with northern brook lamprey preferences with respect to pH, salinity or hardness. In studies of other lamprey species, Potter et al. (1986) found that organic matter, chlorophyll a, macrophyte roots, and low-angle shading are important habitat characteristics for Australian lamprey (Geotria australis) larvae. Beamish and Jebbink (1994) found that small larvae of the southern brook lamprey (Ichthyomyzon gagei) preferred a higher percentage of fine sand in their habitat than did larger larvae. Beamish and Lowartz (1996) found that larval American brook lamprey densities were correlated to the amount of sand and organic matter in the stream substrate.

Habitat trends

In Canada, the northern brook lamprey occurs in many areas that have undergone extensive deforestation due to logging and agriculture. However, no studies exist that specifically examine changes in lamprey habitat over time.

Habitat protection/ownership

In Canada, all publicly owned waters and associated fish habitat within these waters is protected by the federal Fisheries Act. Provincial laws also protect the habitat of this species (e.g. Regulation respecting wildlife habitats in Quebec). Northern brook lamprey may also be found in the following native reservations within its range: Garden River 14, Pays Platt 51, Lake Helen 53A, Fort William 52, Chippewas of Georgina Island, Nawash Burial Ground 1&2, Rankin Location 15D, Red Rock 53, Saugeen 29 and Walpole Island 46. A literature search was performed for Aboriginal traditional knowledge with respect to this species, but provided no new information on the northern brook lamprey.

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