Aquatic Species at Risk - Misty Lake Stickleback (Lentic and Lotic populations)

Description
Habitat
Threats
How You Can Help?
Further Information
Scientific Information

Description
The Misty Lake Stickleback species pair is a small freshwater fish found in a single lake-stream system on Vancouver Island, British Columbia. The pair consists of a lake dwelling (lentic) and a stream dwelling (lotic) variety. The species is a small fish (~51mm length) with three isolated, stout dorsal spines. The body is elongated and laterally thin, tapering where the tail joins the body. The stream form of these pairs is mottled brown and robust-bodied, while the lake form is more darkly coloured, slender-bodied and has longer spines and more gill rakers than the lotic form. The Misty Lake sticklebacks are refered to as a species pair because the two forms live in contact with some overlapping habitat, but there is minimal breeding between the two types meaning that they remain genetically distinct. Given their close proximity and highly divergent characterisitcs, these pairs are invaluable to the study of evolutionary processes.

Habitat
The precise habitat requirements of the species pair are unknown, however Misty Lake is considered to be a natural ecosystem that appears to be stable. Misty Lake is oligotrophic, meaning it has low productivity and low nutrients; it also has very dark stained water. The species habitat use depends on the form of the stickleback. It is thought that the lake form spawns around the edge of the lake in the shallow areas, whereas the stream form makes nests in relatively calm areas of the stream. Both forms overlap in breeding area within the swampy transition zones between the streams and lake. With the exception of breeding, the lake form likely spends the majority of time in the open water of the lake feeding, while the stream form probably occupies low velocity areas in the streams, to feed and rest.

Threats
Due to the limited range of these sticklebacks, they are extremely vulnerable to factors affecting their habitat. Furthermore, changes to the factors that influence mate selection could result in the two forms interbreeding, leading to a hybridized species which is no longer distinctly separate. Some of the potential threats identified to date include non-native species introductions (fish and plants); hydrocarbon and pesticide contamination from the adjacent highway and rest stop; water quality issues and hydrological changes from nearby logging; and non-conforming recreational uses of the lake, such as canoeing and illegal fishing.

How You Can Help?

• Keep invasive species out: Do not release your unwanted pets or plants into lakes or streams. If you wish to canoe on the lake, make sure you clean the bottom of your boat before you put it in the water. These seemingly harmless animals could end up competing with the native species for food or habitat space, or even become predators to the Misty Lake Stickleback species pair. For more information please go to STOP The spread of Invasive Species (http://www.pac.dfo-mpo.gc.ca/publications/docs/invasives-envahissantes-eng.htm)
  
  
• Prevent pollution: Avoid polluting streams, rivers and lakes with garbage, fuel, pesticides or other contaminants. Remember that much of what you pour into your drains will ultimately make it to river systems.
  
  
• Keep Rest Stop areas clean: Always put trash in trash cans, especially near rivers, lakes and beaches.
  
  
• Recyle and reuse: Help reduce waste by recycling or reusing plastic and paper goods.
  
  
• Participate in community consultations: Get involved in Community Working Groups or visit www.pac.dfo-mpo.gc.ca/saraconsultations
  
  
• Volunteer: This may include participating on committees, attending meetings, assisting at educational outreach events, distributing outreach materials, getting involved with a conservation organization, or just simply telling a neighbour or a friend about this species.

This species will get the protection it needs only if all Canadians work together to reduce threats. Find out more and do your best to reduce these threats wherever possible to better protect its habitat. Get involved with the Habitat Stewardship Program for Species at Risk or another conservation organization.

Further Information:
The Misty Lake stickleback pair occurs only in Misty Lake and its inlet and outlet tributary system, which is a sub-basin of the Keogh River drainage on northeastern Vancouver Island. The lake form of the species pair is primarily restricted to Misty Lake proper, although it is occasionally found in the inlet and outlet streams. The stream form occurs in both the inlet and outlet streams, but it has not been found in the lake.

Although several other lake-stream pairs of sticklebacks have been found in British Columbia, the Misty Lake populations appear to be the most genetically and ecologically differentiated from one another. For example, differences in body shape are believed to be adaptations to the different feeding strategies used by each member of the species pair; such observations suggest that the lake population feeds on zooplankton in the open water of the lake, and the stream populations feed on macroinvertebrates.

There have been no empirical estimates of population size for the Misty Lake stickleback species pair although the lake population is believed to be considerably larger than either of the stream populations. Estimates from occasional capture data show that the populations range from a few thousand in the streams up to 10,000 for the lake. Both populations appear to be stable and based on the extent and quality of habitat there is no reason to believe that the historic abundance was significantly greater than it is at present. The life span of the Misty Lake Stickleback species pair is estimated to be 2 to 3 years.

Misty Lake itself and a strip of land around it, as well as about 250 meters of the inlet and outlet streams are located within the boundaries of the Misty Lake Ecological Reserve, established under the Protected Areas of British Columbia Act in 1996 and expanded in 2001. Ecological reserves are areas in British Columbia selected to preserve representative and special natural ecosystems, plant and animal species, features, and phenomena.

Under SARA, a recovery strategy and subsequent action plan must be developed for this species. Additional protection is afforded through the federal Fisheries Act.

Scientific Information:

Scientific Name: Gasterosteus sp.
Taxonomy: Fishes (freshwater)