USFW Service, Fairbanks, Alaska
Not listed under SARA
COSEWIC: Special concern (November 2004)
A long, hard journey home
The Bering cisco should be more famous. We’ve all marveled at the mighty salmon, traveling thousands of kilometers upriver to spawn, but the Bering cisco’s journey is equally extraordinary. This small but powerful traveler, although under a half a metre in size, is known to battle against currents for over 2100 kilometres in its migratory upriver path from the Bering Sea through the Yukon River.
An anadromous silver coloured whitefish, the Bering cisco is a northern dweller that can be found in the Bering, Chukchi and Beaufort seas along the western and northern coast of Alaska; it has also been found along the north eastern coast of Russia (Chukotsk Sea and Kamchatka Peninsula). It is known to migrate into a few Alaskan rivers to spawn, sometimes over long distances. The longest migrations take the Bering cisco into the Canadian portion of the Yukon River which is the only location in Canada it is known to occur.
Information about Bering cisco in Canada is very limited due to its infrequent appearance. Hence, most of the knowledge about this species has been gathered in Alaska where it is abundant. It is a coregonid, meaning a soft-finned fish comprising the freshwater whitefishes, and is often difficult to distinguish from other types. It is anadromous, migrating from salt-water to fresh-water to spawn. Much like the Arctic cisco found in the Mackenzie River and other northwestern Arctic drainages, Bering cisco spawn in fast-flowing water near beds of loose gravel where eggs are broadcast over the substrate. Whether they spawn more than once in their life is unknown, but Bering ciscoes reach sexual maturity between four and nine years of age. The average age of spawning females is age 7; whereas, males average 6 years of age. Fry migrate out of the river and do not appear to spend much time rearing in fresh water.
In Alaska, Bering cisco are targeted by coastal fishers who value them for their high oil content. Although during the summer they are the most abundant whitefish species in the lower Yukon River in Alaska, Bering cisco are not fished heavily in the river since they migrate at the same time as Yukon chinook and chum salmon and fishers are preoccupied with targeting the salmon. Its occurrence over long distances in the Yukon River, and along the Bering coastline, suggest Bering cisco could be an important food source to a number of predators in coastal and riverine environments.
How to recognize the Bering cisco
The Bering cisco resembles a large, plump herring and has a silver-coloured body with moderately sized scales. Those found in the Yukon River average about 34 centimetres (males) to 38 cm (females) in length.. Not to be confused with other species of cisco, the Bering cisco has almost no colour on its pelvic and pectoral fins and has between 18 and 25 gill rakers—bony projections that stop food from escaping its gills—reflective of its preferred diet of small invertebrate organisms.
Bering cisco spends more time in saline waters than other whitefish feeding around river mouths/estuaries and brackish lagoons although they do survive longer periods in salt water. In North America, Bering cisco are most commonly encountered in coastal margins of the Beaufort, Bering and Chukchi seas in Alaska. Bering cisco prefer water that’s not too salty.
Major spawning migrations occur in the Yukon and Kuskokwim rivers in Alaska. In the Yukon River, primary spawning areas occur along the mainstem between Circle and Fort Yukon in Alaska. However some Bering cisco migrate up the Yukon River and reach Canadian waters with sporadic observations as far upstream as Dawson City, Yukon Territory. Traditional knowledge suggests that the distribution in the upper Yukon River is more widespread than currently documented. In the Yukon River, the timing of spawning migrations spans late spring or early summer through fall with peak spawning activity occurring in October. It is possible that the Bering cisco may be found along the Yukon Territory portion of the Beaufort Sea coastline, but its presence there has not been documented or confirmed.
The migratory behaviour of Bering cisco makes the species potentially susceptible to water course obstructions. Alterations to stream flows or changes in the water quality in those areas where they spawn, could also potentially have adverse effects. The Bering cisco is not commercially fished nor does it appear to be at risk of being currently over fished. Based on the sporadic occurrence of Bering cisco in DFO fishwheels operated near the Canada/U.S. border which operate annually from June through October, it is possible that Bering cisco found in the Canadian portion of the Yukon River represent the fringe of a much larger spawning population centred in the upper portions of the Yukon River in Alaska that spills over into Canada in some years. It is not known if spawning occurs in Canada.
The Bering cisco has been nominated by the Committee On the Status of Endangered Wildlife In Canada (COSEWIC) for addition to the federal Species at Risk Act (SARA) as a species of Special Concern. The decision on this recommendation is expected in 2007 after further consultation in the Yukon It is protected by the federal Fisheries Act which prohibits destruction of fish habitat. Projects are currently underway to promote public awareness of the species in the Yukon among fishers, First Nations communities and wildlife management boards, document catches, and to work in conjunction with the Governments of Yukon and Alaska to learn more about this transboundary Yukon River species.
The Bering cisco will get the protection it needs only if we work together to better understand the life history requirements of this rare Canadian fish species and identify critical habitats. As with other fisheries conservation issues, find out more about the species and be aware of human-induced threats. Do your best to reduce these wherever possible to better protect critical habitats and get involved with the Habitat Stewardship Program for Species at Risk(HSP) or another conservation organization in your area.