The Peace/Williston Fish and Wildlife Compensation Program (PWFWCP)

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Burbot
Lota lota

What do they look like?

Burbot have two dorsal fins: the first dorsal is small, but the base of the second dorsal is long (about half the length of the body). The anal fin is also long. The pelvic fins originate in front of the pectoral fins, and the single barbel at the tip of the chin are unique among B.C. freshwater fishes.

Where do they live?

Little is known about burbot habitat use in the Peace/Williston drainage system. Burbot are cool water fish and seldom occur in lakes or rivers where temperatures exceed 18 °C for prolonged periods. Generally, burbot are active at night and inactive during daylight hours. Adult burbot are benthic and rarely enter water less than 2 m deep. In Lake Superior, burbot occur at depths of up to 300 m. The habitats used by adult burbot in rivers are not clear. In northern rivers, adult burbot are associated with the deeper main channels and appear to aggregate at the confluences of clear and turbid rivers.

In the summer, yearling (1+) burbot usually occupy water less than 2 m deep. In Columbia Lake, yearlings were strongly associated with cover (rip-rap jetties and natural boulder areas). As they grow, juveniles shift into progressively deeper water and, in summer, as 2+ or older, usually stay below the thermocline. In rivers, little is known about their habitat use although they are often taken in small tributaries.

In lakes, burbot start life as limnetic larvae: first at moderate depths, then as spring progresses they shift toward the surface, and by mid-summer (at about 15 mm) they move inshore. At 30-40 mm they shift from a limnetic, day-active species to a benthic, night-active species. During the day they hide in coarse gravel along wave-swept beaches, and remain strongly associated with the bottom for the rest of their lives.

What is their life like?

In B.C. burbot exhibit three general life history patterns: lacustrine, riverine, and adfluvial (migrating between rivers and lakes). Riverine and adfluvial populations are normally migratory but even in lacustrine populations some form of migration usually precedes spawning. In lakes, this migration may only involve movement from deep water into shallow areas, but in riverine and adfluvial populations migrations can involve movements of many kilometres.

Burbot aggregate for spawning in winter or very early spring (December to early March). The exact spawning period varies among populations but usually occurs at water temperature ranging from 0-5 °C. Most faunal works indicate burbot spawn at night but some workers have described large "writhing balls" of burbot during the day. Similar burbot "balls", some involving fifty to a hundred individuals, have been photographed in a spring-fed tributary of Columbia Lake. Here, the "balls" dissolve at night when, apparently, actual gamete release occurs. These movements excavate depressions in the substrate and clean the underlying gravel.

In lakes, spawning occurs in relatively shallow water (1.0-10 m) over sand or gravel bottoms. In rivers, burbot spawn in low velocity areas in main channels and in side channels behind deposition bars. The preferred substrate appears to be fine gravel, sand or even silt. There is no evidence of site preparation in rivers and, presumably, eggs and sperm are released into the water just above the bottom.

Burbot are exceptionally fecund and large females often produce over a million eggs. The eggs take from 30 to 60 days to hatch (the exact time depends on temperature) and the small larvae (about 3-4 mm in length) are incompletely developed when first hatched. At first the larvae are planktonic and drift passively, as they grow, however, they become more mobile. Although larvae in lakes start their free-swimming life as part of the plankton community, their early ecology in flowing water (especially swift rivers) is a mystery.

Burbot grow rapidly in their first year and, depending on food resources, reach 100-120 mm by fall. They continue to grow (even in winter) and reach sexual maturity around age seven, although some males delay maturity until 15. Burbot can live for up to 20 years and reach lengths of 700 mm.

What do they eat?

The first food items are small (phytoplankton and rotifers). After the young settle, their diet shifts to include more benthic organisms (e.g., amphipods) and, as they grow, they move into deeper water and gradually increase the proportion of fish in their diet. Adult burbot are primarily piscivores, and in B.C. prey on a wide variety of fish species including trout, grayling, suckers, minnows, and sculpins.

What is their distribution? Burbot are one of the most widely distributed freshwater fish in the Northern Hemisphere. In North America, it ranges in the west from the Seward Peninsula, Alaska, south to the northern parts of Washington, Idaho, and Montana. On the Great Plains burbot occur from the Mackenzie Delta south to Wyoming, and in central and eastern North America from Labrador south to Pennsylvania. In B.C., burbot are widespread in the interior of the province but absent from short coastal drainages and coastal islands (including Vancouver Island and the Queen Charlotte Archipelago). Burbot occasionally stray into the lower part of rivers like the Skeena, Fraser, and Columbia but apparently do not maintain populations in these areas.

View Peace Williston distribution map.