Least Cisco
The least cisco is a slender, silvery whitefish of Canada's Arctic and subarctic drainages — a fish most Canadians never see but one that underpins the food webs of the Mackenzie, Yukon, and Great Slave Lake systems.
It's taken primarily in subsistence and commercial fisheries using gillnets and dip nets, and it's good table fare, though less prized than lake whitefish by those who know both.
Scientific Name: Coregonus sardinella
Also known as Sardine cisco, least whitefish
- Slender, herring-like body; brownish to dark green on the back, bright silver on the sides and belly — easy to mistake for other ciscos at a glance.
- Lower jaw protrudes slightly past the upper jaw when the mouth is closed — the clearest field mark separating it from related species.
- Pelvic fins are dusky to dark, nearly black; anadromous fish also show dark spots on the head, back, and dorsal fin.
- Most fish run 23 cm (about 9 in); a jumbo form found in some Yukon lakes reaches 40 cm (roughly 16 in); maximum recorded length is 47 cm.
What to know
Habitat Distribution
- Native to Canada's Arctic drainages — the Mackenzie River system (south to Fort Simpson), the Yukon River watershed into British Columbia, and Great Slave Lake.
- Some populations are anadromous, moving between Arctic coastal waters and freshwater rivers; others spend their entire lives in lakes or large rivers.
- Occupies rivers, estuaries, and lake systems across the Yukon and Northwest Territories; little is documented about its full Canadian range beyond these core drainages.
- In stratified lakes, concentrates near the thermocline — the cool, oxygen-rich band between warm surface water and cold bottom water, typically at 10–14°C.
Key Locations
- Mackenzie River system, NWT — a core drainage for the species in Canada, documented south to Fort Simpson.
- Great Slave Lake, NWT — present but spawning ecology poorly understood; part of a diverse cisco complex here.
- Yukon River watershed — supports both anadromous and resident populations across the Yukon Territory into British Columbia.
- Some Yukon lakes hold a jumbo form reaching 40 cm, larger than typical river fish.
Specific Spots
- In lakes, the thermocline is the key zone — least cisco pack into this temperature band where food concentrates and predators push up from below.
- In rivers, look for slower side channels and deeper pools, especially in fall when fish stage before spawning over gravel and sand substrates.
- Shallow, turbid gravel areas in fall and early winter are spawning habitat — fish are accessible near shore during this window.
Least Cisco FAQ
Answers from onWater's species guide.
What are the best lures and bait for Least Cisco?
Small jigging spoons (1/16–1/8 oz) and teardrops tipped with maggots, waxworms, or small pieces of fish, effective through the ice when fish are schooled in the thermocline. Small spinners and inline spoons in silver or white work in open-water river fishing, matching the fish's preference for small, flashy forage.
When is the best time to fish for Least Cisco?
Fall (September–October), fish stage near spawning areas in shallow river reaches and lake margins; most accessible to anglers. Winter, ice fishing with small jigs is productive where populations are dense; gillnetting under ice continues in subsistence fisheries.
How do you catch Least Cisco?
Most harvest in Canada happens through subsistence gillnetting, nets set in river channels or under the ice in fall and winter. Where sport fishing occurs, anglers work through the ice with light jigging tackle, targeting schools that concentrate in the thermocline or near spawning gravel in late fall.
What do Least Cisco eat?
Feeds primarily on zooplankton and small invertebrates, tiny crustaceans, insect larvae, and aquatic bugs that concentrate in the thermocline. Small jigs tipped with maggots or waxworms mimic this forage under the ice.
Where do Least Cisco live?
Native to Canada's Arctic drainages, the Mackenzie River system (south to Fort Simpson), the Yukon River watershed into British Columbia, and Great Slave Lake. Some populations are anadromous, moving between Arctic coastal waters and freshwater rivers; others spend their entire lives in lakes or large rivers.
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