Misty Lake sticklebacks COSEWIC asessment and status report: chapter 4

Distribution

Global range

The Misty Lake lake-stream stickleback species pair is only found in the Misty Lake drainage system on northern Vancouver Island, British Columbia, Canada (Figures 4 and figure5). Two other highly divergent lake-stream pairs are known to occur in Mayer Lake (Mayer River drainage) and in Drizzle Lake (Sangan River drainage) on Graham Island, the most northerly of the main Queen Charlotte Islands. The area in northern Vancouver Island where the Misty Lake pair is found is separated by about 400 km of ocean from Graham Island. The Graham Island pairs are morphologically similar but genetically distinct from the Misty Lake lake-stream pair (Thompson et al. 1997).  Although several other lake-stream population pairs of sticklebacks have recently been documented in BC (Hendry and Taylor 2004), none are known to combine the genetic, morphological and ecological differences shown by these three highly divergent pairs, with the possible exception of the Village Bay pair found on Quadra Island near northern Vancouver Island (Hendry and Taylor 2004; Taylor, pers. comm. 2005).  The two mtDNA clades are also known to occur in stickleback on Quadra Island; however, the significance of this for the lake-stream pairs found there is currently unknown as mtDNA has not been examined in the stream form (Taylor, pers. comm.). It is possible that a few additional highly divergent lake-stream pairs will be found in this area (Hendry and Taylor, unpubl. data).

Canadian range

This lake-stream pair of threespine stickleback is found only in Misty Lake (including its outlet) and its inlet stream, which are located approximately 11 km upstream from the ocean in the Keogh River system south of Port Hardy, Vancouver Island, British Columbia.

The extent of occurrence for the Misty Lake form is at maximum about 1.46 km², which includes the surface area of the lake (0.36 km²) plus the watershed area of the outlet (1.1 km²). The extent of occurrence for the inlet stream form is <9 km² (the area of the watershed for the inlet stream); the total length of stream in the inlet system is about 20 km, and the area of occupancy is between 0.008 to 0.04 km². Stickleback do not occupy the entire stream length; however the upper limit of their distribution is unknown. Known upper limits are shown in Figure 6, (Hendry, pers. comm. 2005, 2006; Moore, pers. comm. 2005, 2006); however, no systematic survey of the inlet system has been completed for sticklebacks and they are likely to be found in areas upstream of those markers. The length of stream occupied by the outlet population is about 2.3 km (Moore and Hendry 2005), and area of occupancy is calculated at about 0.01 km². Area of occupancy is estimated using stream length, mean wetted width and an estimate of habitat use of 75% (Moore pers. comm. 2005, 2006) for stream populations.

Figure 4. Map of British Columbia showing global and Canadian range of the Misty Lake sticklebacks on Vancouver Island. Arrow indicates location of Misty Lake drainage.

Figure 4.  Map of British Columbiashowing global and Canadian range of the Misty Lake sticklebacks on Vancouver Island. Arrow indicates location of Misty Lake drainage.

Figure 5. BC Parks map showing Misty Lake watershed, boundary of ecological reserve and highway adjacent to southern boundary of reserve.

Figure 5.  BC Parks map showing MistyLakewatershed, boundary of ecological reserve and highway adjacent to southern boundary of reserve.

Figure 6. Known upper and lower limits of the Misty Lake lake-stream stickleback distribution (Moore, pers. comm.; Hendry, pers. comm. 2005, 2006).

Figure 6.  Known upper and lower limits of the Misty Lake lake-stream stickleback distribution (Moore, pers. comm.; Hendry, pers. comm. 2005, 2006).

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