Coastrange Sculpin (Cultus population)

Cottus aleuticus

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 Coastrange Sculpin (Cultus Population) is also known as the Cultus Pygmy Sculpin. This species is most likely a postglacially derived form of the Coastrange Sculpin. Cultus Lake was only accessible to fish colonization eight to ten thousand years ago. Thus, the Cultus Pygmy Sculpin represents an example of rapid and possibly ongoing evolution. The species is particularly interesting because similar forms have also evolved in two Washington State lakes.

The Cultus Pygmy Sculpin is a small fish that reaches a maximum length of 50 millimetres. The top of its body is brown to grey with dark blotches, while the bottom is nearly white. Spawning males are darker with an orange band on the first dorsal fin. Two to four dark saddle-like blotches are found under its second dorsal fin. Adult fins have pigments, usually shaped like bars.

The species is morphologically and ecologically different from other Coastrange Sculpin. Specifically, the fish are smaller, retain larval behaviours, and live in open water habitat.

Habitat

This small fish is found only in Cultus Lake, British Columbia, Canada. Cultus Lake is a low-elevation montane lake that drains into the Vedder River, a tributary of the Lower Fraser River. The lake is 41.8 metres deep and has a surface area of 6.3 square kilometres.

The Cultus Pygmy Sculpin is restricted to the offshore habitat of Cultus Lake. Direct spawning of the species has not been observed. It is believed to take place in deeper waters of the lake or on shoals near inlet creeks. As adults, Cultus Pygmy Sculpin continue their larval behaviour of migrating into surface waters at night.

Threats

The species' limited range makes it very vulnerable to threats. Any change to the Cultus Lake ecosystem could threaten the species. Local threats to the Cultus Pygmy Sculpin include invasive species, changing trends in predator and competitor populations, water quality, water use, water-oriented recreation, and land use.  Invasive species could threaten the Cultus Pygmy Sculpin through competition for food, direct predation, or habitat modification. The species is currently preyed on by several fish species in the lake. There is a concern that predation rates could be altered through stocking or enhancement. Stocking could potentially result in greater predation or competition pressure, depending on the species. Pollution from recreation and land use is also a concern for the species. These activities can cause decreases in water quality and degradation of aquatic habitat.

Climate change and its effects on precipitation, water flow, and temperature may threaten the Cultus Pygmy Sculpin.

Further Information

The Cultus Pygmy Sculpin was assessed as Threatened by the Committee on the Status of Endangered Wildlife in Canada in 2000 and listed under the Species at Risk Act in 2003. The species' status was reassessed and confirmed in 2010. A Recovery Strategy and an Action Plan have been developed for the species. The documents outline ways to support the Cultus Pygmy Sculpin population in the wild.

Studies have been conducted to learn more about the species' habitat use, life stages, and abundance. The species has also probably benefited from several educational activities to increase public environmental awareness of Cultus Lake.

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.