Vancouver (Cowichan Lake) Lamprey

Entosphenus macrostomus

SARA Status
No Status
NS
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

SARA Status

  • No Status NS
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX
COSEWIC Status
Not at Risk
NR
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

COSEWIC Status

  • Not at Risk NR
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX

Description

The Vancouver Lamprey (Lampetra macrostoma), now known as the Cowichan Lake Lamprey, is an eel-like parasitic fish. In its parasitic phase, the species feeds by attaching itself to other fish, such as cutthroat trout. The Cowichan Lake Lamprey evolved from the Pacific Lamprey (Entosphenus tridentatus), a species of lamprey commonly found throughout the North Pacific Ocean. 

The Cowichan Lake Lamprey is scaleless and jawless, like all lamprey species. Larval forms of the species are called ammocoetes and lack teeth and fully developed eyes. After they go through metamorphosis, they develop a circular-shaped mouth (or oral disc). The oral disc has dentition unique to the species. Adults have large eyes located high on the head compared to other lamprey species. The species is blue-black or dark brown in colour. A fully grown Cowichan Lamprey can reach lengths of up to 27 centimetres.

Habitat

The Cowichan Lake Lamprey is endemic only to southern Vancouver Island in Canada. The species is only found in Cowichan, Mesachie and Bear Lakes, and their tributaries. The species has a single population. Sampling studies suggest the species has declined from the 1980s to 2015. However, few studies occurred between the late 1980s and 2010.

Cowichan Lake Lampreys use both the nearshore environment and open waters of lakes. They spawn in gravel bars in shallow nearshore lake habitat around tributaries. After hatching, ammocoetes drift from the nest and burrow into soft fine sediment or sand. Cowichan Lake Lampreys likely require moving water for successful spawning and egg incubation.

Little is known about the behaviour of the Cowichan Lake Lamprey during its parasitic phase. It is known that it parasitizes salmonids.  Lamprey scars are commonly found on cutthroat trout or other recreationally caught fish. 

Threats

As the Cowichan Lake Lamprey has a small range, the species is very vulnerable to threats. Key local threats to the species are related to humans. They include water and land use, recreational activities, alteration of prey base, and poor water quality. Changes in water use by active water licence holders could negatively impact the species’ habitat or prey.

The potential impacts of such events coupled with climate change are also a cause for concern for the Cowichan Lake Lamprey. The species may be affected through changes in precipitation, water flow and temperature. In years of drought, if water is drawn down from Cowichan Lake through the weir, spawning and rearing habitats in the nearshore can be de-watered. This may directly impact the abundance of the species. 

Forestry and other land-based activities, such as development, can alter aquatic habitat through water pollution, increase sedimentation, alter run-off rates, and destroy riparian habitat.

The Cowichan Lake Lamprey exists in a recreational area popular with locals and tourists. Fishing, boating, swimming and hiking all frequently take place in the species’ habitat. These activities can alter prey base, pollute water, and disturb or destruct nearshore areas.

Further information

The Cowichan Lake Lamprey was listed under the Species at Risk Act as Threatened in June 2003.  In 2007, a Recovery Strategy for the species was published. The strategy outlines goals to maintain and enhance the habitat of the species. It also sets targets to increase knowledge and understanding of the Cowichan Lake Lamprey. Work has been underway to address these knowledge gaps.

There are also many ongoing recovery activities for the Cowichan Lake watershed. Although not all activities focus on the Cowichan Lake Lamprey and its habitat, the species probably benefits from general stewardship of its watershed.

This species is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available on the Species at Risk Public Registry.

To find out if this species is protected by provincial or territorial laws, consult the provinces' and territories' website.