Misty Lake Sticklebacks

Photo of Misty Lake stickleback, by A. Hendry.

Species at Risk Act

Status: no status (not on SARA list)

Recovery Strategy: in preparation

COSEWIC Summary

Date of Assessment: November 2006

Common Name: Misty Lake sticklebacks (lentic and lotic)

Scientific Name: Gasterosteus spp.

COSEWIC Status: Endangered

Reason for Designation: This endemic, highly divergent fish species pair is restricted to a single stream-lake complex on Vancouver Island with an extremely small area of occurrence.  This species pair could quickly become extinct due to the introduction of non-native species or perturbations to the habitat.  Proximity of this complex to a major highway and public access make an introduction likely.  Logging activities in the watershed, as well as highway use and related maintenance, could impact habitat quality to some degree.

Canadian Occurrence: British Columbia

COSEWIC Status History: Designated Endangered in November 2006. Assessment based on a new status report.

Brief Description of Misty Lake Sticklebacks and Their Habitat

The threespine stickleback (Gasterosteus aculeatus) is a small (usually 35-55 mm) fish that is common in coastal marine and freshwater throughout the northern hemisphere. The marine form is assumed to be the ancestral form to most freshwater forms, and is usually anadromous, meaning it returns to freshwater to reproduce.

Lake- and stream-dwelling sticklebacks are common in BC, but parapatric pairs (meaning the distribution of the two forms is essentially separate but with an area of contact or overlap, where the two interact) are rare. Parapatric pairs have been well-described for three lakes in BC: Mayer and Drizzle Lakes on the Queen Charlotte Islands and Misty Lake on northern Vancouver Island. Lake and stream parapatric pairs occur in other British Columbia watersheds, but the Mayer, Drizzle and Misty pairs have been the best-described, are demonstrably divergent, and are almost certainly independently derived.

Within the Misty Lake system there is a distinct lake-dwelling form and an inlet and outlet stream form. Individuals in the inlet stream are more dissimilar from the lake form than are individuals from the outlet stream, and there is likely greater gene flow between the lake form and the outlet form than between the lake and the inlet form.

Studies of Misty Lake sticklebacks have focussed on evolutionary processes, and we have relatively little information on the Misty Lake pair from ecological or behavioural studies. However, it is likely reasonable to assume their biology is similar to other stream- and lake-dwelling populations.

Diet of Misty Lake sticklebacks has not been studied in detail, but based on feeding morphology the lake form is presumed to feed primarily on zooplankton and the stream form on benthic macroinvertebrates.

The Misty Lake stickleback species pair occurs only within the Misty Lake watershed, which is itself a sub-basin of the Keogh River drainage on northern Vancouver Island. Misty Lake is a small coastal lake (35.6 ha), approximately 12 km upstream of the ocean. The lake and streams have other fish species, including cutthroat trout, rainbow trout, coho salmon, Dolly Varden and prickly sculpin.

Misty Lake occurs at 75 m elevation, has a surface area of 35.6 ha, and a well-defined inlet and outlet stream. The lake is relatively shallow, with a maximum depth of 6.7 m, and mean depth of 1.7 m. The water is deeply stained, with a Secchi depth of less that 1 m.

Given their restricted distribution, Misty Lake sticklebacks can be considered vulnerable to a variety of threats, including exotic species, water quality, land use, water use, and climate change.

The Misty Lake Ecological Reserve was established in 1996 with the primary intent of protecting sticklebacks in the lake. The reserve is 55 ha in total area, which represents the lake itself and a strip of land around it. All consumptive resource uses and the use of motorized vehicles are prohibited within ecological reserves. The Misty reserve affords protection to less than 250 m of the inlet and outlet stream. The portions of stream beyond the reserve’s boundary are crown or private property.

Some References

Bell, M. A. and S. A. Foster. 1994. The evolutionary biology of the threespine stickleback. Oxford University Press, Oxford, UK.

COSEWIC. 2006. COSEWIC assessment and status report on the Misty Lake sticklebacks Gasterosteus sp. (Misty Lake lentic stickleback and Misty Lake lotic stickleback) in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vii + 27 pp.

Government of Canada. 2005. Species at Risk Act Policy. Policy on the feasibility of recovery. Draft, January 06, 2005.

Hendry, A. P. and E. B. Taylor. 2004. How much of the variation in adaptive divergence can be explained by gene flow? An evaluation using lake-stream stickleback pairs. Evolution 58:2319–2331.

Hendry, A. P., E. B. Taylor, and J. D. McPhail. 2002. Adaptive divergence and the balance between selection and gene flow: lake and stream stickleback in the Misty system. Evolution 56:1199–1216.

Lavin, P. A. and J. D. McPhail. 1993. Parapatric lake and stream sticklebacks on northern Vancouver Island: disjunct distribution or parallel evolution? Canadian Journal of Zoology 71:11-17.

McKinnon, J. S. and H. D. Rundle. 2002. Speciation in nature: the threespine stickleback model systems. Trends in Ecology & Evolution 17:480-488.

McPhail, J. D. 1994. Speciation and the evolution of reproductive isolation in the sticklebacks (Gasterosteus) of southwestern British Columbia. Pages 399-437 in M. A. Bell and S. A. Foster, editors. The evolutionary biology of the threespine stickleback. Oxford University Press, Oxford, UK.

Moodie, G. E. E. 1972. Morphology, life history, and ecology of an unusual stickleback (Gasterosteus aculeatus) in the Queen Charlotte Islands. Canadian Journal of Zoology 50:721-732.

Moore, J. S. and A. P. Hendry. 2005 Both selection and gene flow are necessary to explain adaptive divergence: evidence from clinal variation in stream stickleback. Evolutionary Ecology Research 7:871–886.

Stinson, E. M. 1983. Threespine sticklebacks (Gasterosteus aculeatus) in Drizzle Lake and its inlet, Queen Charlotte Islands: ecological and behavioural relationships and their relevance to reproductive isolation. M. Sc. thesis, Department of Zoology, University of Alberta, Edmonton.

Wooton, R. J. 1976. The biology of the sticklebacks. Academic Press, London, UK.

Recovery Team Documents

Critical habitat for stickleback species pairs (draft for PSARC review, 30 July 2008)

password-protected link for members of the Recovery Team