Aquatic Species at Risk - Nooksack Dace

Species - Details

Nooksack Dace

Scientific name:
Rhinichthys sp.
Taxonomy:
Fishes (freshwater)
Status:
Endangered, listed under SARA
Region: Pacific

At a glance

A relatively small freshwater fish, the Nooksack dace takes its name from a river in Washington State. At one time, it was plentiful in BC and Washington state—but not today. The Nooksack dace has started to disappear from its native territory as a result of construction, development and other human activities. Through the Species at Risk Act—and through stewardship activities that have been ongoing since the 1990s—people are working to prevent this shallow-water fish from becoming extinct.

About the Nooksack dace

Twelve thousand years ago, the majority of British Columbia lay beneath a sheet of ice more than a kilometre thick. For thousands of years, the ice isolated Washington State’s Chehalis River from the rest of the continent. Unable to interbreed with other populations of their own species, the River’s fish began to evolve. The result was the Chehalis fauna—a community of fish species found nowhere else. When the ice sheet retreated, this unique community began to disperse. One species, the Nooksack dace, migrated north and was among the first fish to re-colonize the newly ice-free rivers of what is now the Fraser River Valley.

Fully grown, the Nooksack dace averages 10 cm in length. Adults eat insect larvae and young dace feed on midge pupae and small crustaceans.

How to recognize it

The Nooksack dace is grayish-green in colour on top and dirty- to silvery-white underneath, with a brass-coloured stripe over the lateral line and (sometimes) a black stripe in front of the eyes. The fish may have speckles on its lower side, and has distinctive pale markings at the base of its dorsal fin that are visible from above. The dace is rounded on top and flat underneath, with a long nose that overhangs its mouth.

Nooksack Dace
Mike Pearson

Where the Nooksack dace Lives

In British Columbia, the Nooksack dace is found in three small streams that feed into the Nooksack River in lower Fraser Valley around Abbotsford, Aldergrove and Clearbrook. Its range reaches all the way into northwestern Washington. Adult members of the species are usually found in riffles—shallow parts of streams where water flows brokenly—with gravel or stony bottoms. Young dace are found most often in shallow, slow waters with sandy or muddy bottoms.

Why it’s at risk

The main threat to the Nooksack dace comes from human intrusions into its natural habitat—caused largely by the growth of communities at the headwaters of streams occupied by the species. The major threat in Canada is lack of water in their habitat, during late summer drought conditions. South of the border, parts of certain creeks have become ditched and silted, making them unsuitable for the fish. Measurements indicate that the BC population of dace is growing smaller, and it is certainly gone from sites where it had been found as late as the 1960s.

What’s Being Done

The Nooksack dace is listed as endangered and protected under the federal Species at Risk Act (SARA). Recovery strategies and action plans are being developed under SARA. Habitat studies and ecological research have been ongoing since the 1990s, as have assessments of municipal regulations in areas where Nooksack dace habitat is being affected by human development.

Education and stewardship programs have been in place since the 1990s. A five-year habitat restoration project was launched in 1998, as were numerous species-recovery activities such as building fish-ways around dams. Habitat-related efforts continue today—in which community involvement is being promoted as essential.

Helpfully, the BC government has taken steps to protect another endangered fish, the Salish sucker; those efforts will benefit the dace as well, as the two fish share much of the same territory.

Consult the Recovery Strategy for Nooksack dace :
Recovery Strategy for Nooksack Dace (Rhinichthys cataractae) in Canada (2006)

What can you do?

The Nooksack dace will get the protection it needs only if all Canadians work together to reduce threats. Find out more about the Nooksack dace and be aware of human-induced threats. Do your best to reduce these threats wherever possible to better protect the Nooksack dace's critical habitat. Get involved with the Habitat Stewardship Program for Species at Risk (HSP) or another conservation organization.