Burbot is the only cod species that lives in fresh water. It is found in clear moving water or in clean deep lakes. During the day, the fish hides in the depths or under stones or hollows. The fish hunts actively at dusk and at night. Just like cod, it has a barbel on its chin, which it uses to search the bottom for food. When the burbot is young, it eats mostly insect larvae, gammarids and water louse. After growing to 20-40 centimeters, the fish switches over to a diet of fish.

The only member of the family which lives in freshwater. Crepuscular and nocturnal (Ref. 11941). Found in well oxygenated flowing waters and large lakes. Occurs from estuaries of large lowland rivers as well as from small mountain streams, preferring deep waters in summer (Ref. 59043). Also inhabit deep lakes and large rivers (Ref. 5723, 10294) with slow-moving current. Seek shelter under rocks, in crevices on the river banks, among roots of trees and dense vegetation (Ref. 30578, 10294). Those in rivers tend to congregate in deep holes throughout the year, except at spawning (Ref. 27547). Movements into shallower water during summer nights are related to feeding (Ref. 1998). Smaller individuals feed on insect larvae, crayfish, mollusks and other invertebrates with a changing preference for fishes in larger individuals (Ref. 1998, 10294). Source of oil. Sold mainly salted. Liver is sold smoked or canned in Europe (Ref. 1998). Processed into fishmeal (Ref. 1998). Because of its nocturnal habits and its slow movements, this fish is not very much appreciated by sport fishermen. Flesh is tasty but a little dry (Ref. 30578). Locally threatened due to river regulation (Ref. 59043).

http://www.dnr.state.mn.us/minnaqua/speciesprofile/burbot.html

MN DNR MinnAqua Program Species Profile

Close Up on the Burbot

by Mike Kurre, Mentor Coordinator

Burbot:

Lota lota (low’-tah low’-tah): from the French word for codfish; “burbot” is also a French word, meaning “mud” or “mire”

Ur, Ur, Ur! spoke the burbot. . .

What’s in a name any way? Burbot is only one of numerous names this cold-water species from the cod family goes by. Many of the fresh water cod’s nick-names can’t be mentioned, but here is a list of the most common: Eel Pout, Lawyer, Ling, Cusk, Lush, Loche, Mudblow and Poor Man’s Lobster.

Burbot can be found in most Minnesota northern lakes and rivers, including Lake Superior, but can also be found in small numbers in the prairie regions and parts of the lower Mississippi. They are good indicators of a healthy watershed. Typically they require water temps lower than 70 degrees during the summer and are a rare catch, but come winter-time, these predators come alive and are most active.

Identification

The burbot coloration varies from yellow-brown to brown or even dark olive with black mottling and blotching, giving it almost a camouflage appearance. Burbot resembles an eel more than other freshwater fish. Its scales are small, the skin has a slimy feel and this bottom hugger has large chin barbel with tubular nostrils similar to catfish, for detecting food.

This secretive fish can live up to the ripe old age of 15 and the Minnesota state record is 19 lbs. 3 ozs. and was caught in Lake of the Woods. These fish can weigh over 60 lbs in other areas of the world. Typically in Minnesota, they are under 8 lbs. and are less than 28 inches in length.

Handling

Burbot can be handled by placing a firm grip just behind the head. Their teeth are much like largemouth bass, like rough sandpaper. Don’t be shocked when our eel-like looking friend, uniquely and harmlessly, wraps its body around your forearm and gives you a little…. ur…ur…ur, vocalization when handling them. It’s just their way of greeting you.

Food

They eat mostly other fish such as small yellow perch and walleyes, but also consume fish eggs, clams, crayfish, mayfly larvae and other aquatic insects.

Reproduction

The spawning season for this unique fish is very unusual. It spawns during mid-winter into early spring, before the ice is off the lake or river. Reproduction occurs in pairs or sometimes in groups of dozens or even in the hundreds, in shallow water over sand or gravel bottoms. There is no nest built and no care for the eggs or newly hatched young. After the release of eggs and sperm the fish thrash about scattering the eggs, which later fall to the bottom. A single female can lay as many as 1 million eggs depending on her size. The embryos develop for 4 to 5 weeks in the cold water and hatch at the tiny size of .15 inches (one of the smallest freshwater fish larvae).

Predators

Young burbots are common prey for many fish, such as smallmouth bass, yellow perch, smelt, lake trout and muskie. Humans also can be considered a predator even though many people consider burbot the “ish” in fish and most folks don’t even like to touch them. Folks who cut the line not knowing that baked with a little butter, salt and pepper, miss out on a delicacy served in many households.

Tackle & Fishing Tips

Most burbots are accidentally caught by anglers targeting other fish like walleyes (that would be me). They are especially active during low light conditions during the winter months. Tip-ups or walleye style jigging equipment, spooled with 4 to 8 lb line will provide the necessary gear needed to land these unique creatures.

Your bait of choice can be just about any minnows, locating the bait within inches of a deep muddy river- or lake-bottom (like the mud flats in Lake Mille Lacs). Keep a watchful eye on your line; Burbot have very sensitive bite. Wait too long to set the hook and you’ll be fishing-out your hook from the gullet or cutting your line to make an ethical release.

Burbot do not have special conservation status in Minnesota and are not actively managed, so fish away and enjoy another special offering from the lakes of Minnesota.

Fun Facts

* Burbot have long been used for fish meal, oil and food for animals raised for furs (the oil is absorbed through digestion making for a great fur conditioner).

* The tough skin was once used in the windows of Siberia as a substitute for glass.

* Burbots are part of an annual celebration in February in Walker, MN. The Eelpout Festival has been a great event, distracting Minnesotan’s during winters for over 30 years.

Black Sea, British Columbia, Canadian Exclusive Economic Zone [Pacific part], Coastal Waters of Southeast Alaska and British Columbia, FAO fishing area 67, Hudson Bay, Hudson Strait, North East Pacific, North Pacific, North West Territories, Polish Exclusive Economic Zone, Swedish Exclusive Economic Zone

Burbot, Lota_lota, are a holarctic species native to the cold fresh waters of the Nearctic and Palearctic regions found between 40 and 70 degrees North latitudes.

Biogeographic Regions: nearctic (Native ); palearctic (Native )

Other Geographic Terms: holarctic

Circumarctic in freshwater (Ref. 1371). Europe: Loire drainage, France eastward to White, Barents and Arctic Sea basins; upper Volga drainage; western Caspian basin; rivers draining to Black Sea; Rhône drainage (France); in Italy native only in Po drainage; eastrward England (now extirpated). In Siberia eastward to River Lena. Reported that populations from eastern Siberia and North America belong to a different species, Lota maculosa (Ref. 59043).

Europe: from Loire drainage (France) eastward to White, Barents and Arctic Sea basins; upper Volga drainage; southeastern Caspian basin; rivers draining to Black Sea; Rhône drainage (France); in Italy, native only in Po drainage; eastern England (now extirpated). In Siberia eastward to River Lena. Originally absent from Iberian Peninsula, central and southern Italy, Adriatic basin, Greece, Ireland, western and northern Great Britain and western France.

Burbot, Lota lota, are a holarctic species native to the cold fresh waters of the Nearctic and Palearctic regions found between 40 and 70 degrees North latitudes.

Biogeographic Regions: nearctic (Native ); palearctic (Native )

Other Geographic Terms: holarctic

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Widely distributed in both hemispheres south to about 40 degrees north latitude (south to Pennsylvania, Kentucky, Missouri, Wyoming, and Oregon).

Europe to Asia and North America.

Burbot are large fish known to grow to as much as 1.5 m in length and 34 kg in mass (Morrow 1980). These fish are yellow, light tan, or brown with dark brown or black patterning on the body, head and most fins. The underbelly and pectoral fins are pale to white (Cohen et al. 1990; Morrow 1980). The first dorsal fin is short and is followed by a long second dorsal fin at least 6 times the length of the first and joined to a rounded caudal fin (Morrow 1980). Burbot have neither dorsal nor anal spines and have 67 to 96 soft dorsal rays, and 58 to 79 soft anal rays (Cohen et al. 1990). Gill rakers are short, pectoral fins are rounded, and caudal fins have 40 rays (Morrow 1980). Like other cods, burbot are also characterized by a single barbel located on the chin (Morrow 1980).

Range mass: 34 (high) kg.

Range length: 152 (high) cm.

Range basal metabolic rate: 171.6 (high) cm^3 oxygen/hour.

Average basal metabolic rate: 73.9 cm^3 oxygen/hour.

Other Physical Features: ectothermic ; bilateral symmetry

Sexual Dimorphism: sexes alike

Dorsal spines (total): 0; Dorsal soft rays (total): 67 - 96; Analspines: 0; Analsoft rays: 58 - 84; Vertebrae: 50 - 67

Burbot are large fish known to grow to as much as 1.5 m in length and 34 kg in mass (Morrow 1980). These fish are yellow, light tan, or brown with dark brown or black patterning on the body, head and most fins. The underbelly and pectoral fins are pale to white (Cohen et al. 1990; Morrow 1980). The first dorsal fin is short and is followed by a long second dorsal fin at least 6 times the length of the first and joined to a rounded caudal fin (Morrow 1980). Burbot have neither dorsal nor anal spines and have 67 to 96 soft dorsal rays, and 58 to 79 soft anal rays (Cohen et al. 1990). Gill rakers are short, pectoral fins are rounded, and caudal fins have 40 rays (Morrow 1980). Like other cods, burbot are also characterized by a single barbel located on the chin (Morrow 1980).

Range mass: 34 (high) kg.

Range length: 152 (high) cm.

Range basal metabolic rate: 171.6 (high) cm^3 oxygen/hour.

Average basal metabolic rate: 73.9 cm^3 oxygen/hour.

Other Physical Features: ectothermic ; bilateral symmetry

Sexual Dimorphism: sexes alike

Maximum size: 1520 mm NG

152 cm TL (male/unsexed; (Ref. 27547)); max. published weight: 34.0 kg (Ref. 27547); max. reported age: 20 years (Ref. 556)

Length: 84 cm

Diagnosed from all other freshwater fishes in Europe by its pelvic fin origin anterior to pectoral fin origin and by having one central barbel on lower jaw (Ref. 59043). Distinguished by the long second dorsal fin, at least 6 times as long as the first, and a single barbel on the chin (Ref. 27547). Gill rakers short (Ref. 27547). First dorsal short; second dorsal and anal fins joined to caudal; pectorals short and rounded; caudal rounded (Ref. 27547), with 40 rays (Ref. 2196). Color is yellow, light tan to brown with a pattern of dark brown or black on the body, head and fins (Ref. 1371). Pelvic fins pale, others dark and mottled (Ref. 27547).

This taxon is one of a number of demersal species in the Seine River system of Western Europe. Demersal river fish are found at the river bottom, feeding on benthos and zooplankton

The Marne and Yonne exhibit the greatest torrential flows, due to the percentage of their courses underlain by impermeable strata, in combination with the river gradients. Although the Loing manifests the highest percentage of impermeable strata of all the tributaries, its low gradient mitigates against torrential velocities. Thus the majority of the Seine and its tributaries exhibit a relaxed generally even flow rate.

Seine water pollutant loads of heavy metals, nutrients, sediment and bacteria are relatively high, especially influnced by wastewater and surface runoff from Paris and its suburbs. Parisian pollutant loadings are noted to be particularly high during periods of high rainfall, not only due to high runoff, but also from the inadequate sewage treatment facilities in periods of high combined wastewater/stormwater flow.

Heavy metal concentrations at Poses weir reveal the following levels: copper, 1.9 milligrams per liter; cadmium, 32 mg/l; and lead, 456 mg/l. Concentrations of zinc are also quite high, making the Seine Estuary one of the most highly contaminated estuaries in the world with respect especially to lead and cadmium. Significant amounts of toxic pollutants are also attached to sediments deposited in the Seine during the last two centuries, including mercury, nickel, chromium, toluene, DDT and a variety of herbicides and pesticides. Downriver from Paris, significant quantites of ammonium are discharged into the Seine from effluent of the Achères wastewater treatment plant.

There are a total of 37 fish species inhabiting the Seine, and another two taxa that are known to have been extirpated in modern times. Two of the largest aquatic fauna known to have lived in the Seine are now locally extinct: the 500 centimeter (cm) long sturgeon (Acipenser sturio) and the 83 cm long allis shad (Alosa alosa).

The largest extant native demersal (species living on or near the river bottom) taxa in the Seine are:

the 133 cm European eel (Anguilla anguilla);

the 150 cm northern pike (Esox lucius);

the 120 cm sea lamprey (Petromyzon marinus); and,

the 152 cm Burbot (Lota lota).

This taxon is one of a number of demersal species in the Amur River system. Demersal river fish are found at the river bottom, feeding on benthos and zooplankton

The persistence of mercury contamination in Amur River bottom sediments is a major issue, arising from historic cinnabar mining in the basin and poor waste management practises, especially in the communist Soviet era, where industrial development was placed ahead of sound conservation practises.

The largest native demersal fish species in the Amur River is the 560 centimeter (cm) long kaluga (Huso dauricus); demersal biota are those that inhabit the bottom of a surface water body. Another large demersal fish found in the Amur is the 300 cm Amur sturgeon (Acipenser schrenckii), a taxon which is endemic to the Amur basin.

Other demersal endemic fish species (all in the concubitae family) of the Amur Basin are Iksookimia longicorpa, I. koreensis, I. hugowolfeldi, Cobitis melanoleuca melanoleuca and the Puan spine loach (Iksookimia pumila).

Burbot are demersal fish found in deep temperate lake bottoms and slow moving cold river bottoms between 4 and 18 degrees C (Riede 2004; Cohen et al. 1990). Primarily found at depths ranging from 1 to 700 m, these fish prefer fresh waters but are also found in some brackish water systems (Cohen et al. 1990). These fish often dwell among benthic refugia such as roots, trees, rocks, and dense vegetation (Billard 1997).

Range depth: 1 to 700 m.

Habitat Regions: temperate ; freshwater

Aquatic Biomes: benthic ; lakes and ponds; rivers and streams; brackish water

demersal; potamodromous (Ref. 51243); freshwater; brackish; pH range: 7.5; dH range: 18; depth range 1 - 700 m (Ref. 1998)

Habitat and Ecology

Systems

• Freshwater

Burbot are demersal fish found in deep temperate lake bottoms and slow moving cold river bottoms between 4 and 18 degrees C (Riede 2004; Cohen et al. 1990). Primarily found at depths ranging from 1 to 700 m, these fish prefer fresh waters but are also found in some brackish water systems (Cohen et al. 1990). These fish often dwell among benthic refugia such as roots, trees, rocks, and dense vegetation (Billard 1997).

Range depth: 1 to 700 m.

Habitat Regions: temperate ; freshwater

Aquatic Biomes: benthic ; lakes and ponds; rivers and streams; brackish water

Depth range based on 305 specimens in 1 taxon.
Water temperature and chemistry ranges based on 8 samples.

Environmental ranges
  Depth range (m): 0.09 - 38
  Temperature range (°C): 6.107 - 7.379
  Nitrate (umol/L): 1.212 - 1.615
  Salinity (PPS): 6.858 - 6.901
  Oxygen (ml/l): 8.187 - 8.276
  Phosphate (umol/l): 0.236 - 0.274
  Silicate (umol/l): 12.053 - 12.992

Graphical representation

Depth range (m): 0.09 - 38

Temperature range (°C): 6.107 - 7.379

Nitrate (umol/L): 1.212 - 1.615

Salinity (PPS): 6.858 - 6.901

Oxygen (ml/l): 8.187 - 8.276

Phosphate (umol/l): 0.236 - 0.274

Silicate (umol/l): 12.053 - 12.992
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Habitat Type: Freshwater

Comments: Common in deep (to at least 90 m) cold waters of lakes, reservoirs, and large rivers. In summer, stays in deep cold waters but may move into shallower water at night. Life history may be confined to lakes or rivers or may migrate between lake and riverine habitats; all three patterns may occur within a single river basin. Often exhibits a post-spawning movement into tributary rivers in late winter and early spring. Spawns usually in lakes but may move into rivers to spawn. River-spawning populations prefer low-velocity areas in main channels or in side channels behind deposition bars (see USFWS 2003). Broadcasts eggs usually over sand or gravel (sometimes silt) in up to about 10 ft of water (Scott and Crossman 1973).

Depth: 1 - 700m.
From 1 to 700 meters.

Habitat: demersal.

Potamodromous. Migrating within streams, migratory in rivers, e.g. Saliminus, Moxostoma, Labeo. Migrations should be cyclical and predictable and cover more than 100 km.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

May move long distances between spawning and nonspawning habitats (usually 1 to 25 km, but up to 120 km in the Kootenai River) (see USFWS 2003). May move from lake into stream to spawn (Scott and Crossman 1973). Basically sedentary during nonspawning season.

Newly hatched burbot are completely planktivorous, and remain so even when they are no longer gape limited (Ghan and Sprules 1993). Diet of larval burbot is dominated by rotifer species for the first two weeks. Diet then shifts to slightly larger nauplii, changing further during week four to cycloid copepoda, daphnia, and calanoid copepoda (Ghan and Sprules 1993). Juveniles have a diet of mollusca and insecta larvae (Tolanen et al. 1999). Adult burbot are piscivorous and consume over 99% actinopterygii by mass in Lake Superior (Bailey 1972). Though burbot are always a primarily piscivorous fish, their diet changes seasonally and in response to competition. After the winter months, Tolanen et al. (1999) found that burbot ate a much higher proportion of aquatic invertebrates, namely crustacea in the early summer and mysida in the fall. In the Vilyusk resevoir, diet overlap with pike forces burbot to broaden their diet breadth to include more benthic invertebrates (Kirillov 1988). In addition to actinopterygii and invertebrates, Bailey (1972) also found rocks, wood chips, plastic, and other inert materials in burbot stomachs, indicating that burbot feeding habits were somewhat indiscriminate.

Animal Foods: fish; insects; mollusks; aquatic or marine worms; aquatic crustaceans; zooplankton

The only member of the family which lives in freshwater. Crepuscular and nocturnal (Ref. 11941). Inhabits deep lakes and large rivers (Ref. 5723) with slow-moving current. Seeks shelter under rocks, in crevices on the river banks, among roots of trees and dense vegetation (Ref. 30578). Those in rivers tend to congregate in deep holes throughout the year, except at spawning (Ref. 27547). Movements into shallower water during summer nights are related to feeding (Ref. 1998). Smaller individuals feed on insect larvae, crayfish, mollusks and other invertebrates with a changing preference for fishes in larger individuals (Ref. 1998). Feeds mainly on fish (Ref. 13439).

Newly hatched burbot are completely planktivorous, and remain so even when they are no longer gape limited (Ghan and Sprules 1993). Diet of larval burbot is dominated by rotifer species for the first two weeks. Diet then shifts to slightly larger nauplii, changing further during week four to cycloid copepods, daphnia, and calanoid copepods (Ghan and Sprules 1993). Juveniles have a diet of molluscs and insect larvae (Tolanen et al. 1999). Adult burbot are piscivorous and consume over 99% fish by mass in Lake Superior (Bailey 1972). Though burbot are always a primarily piscivorous fish, their diet changes seasonally and in response to competition. After the winter months, Tolanen et al. (1999) found that burbot ate a much higher proportion of aquatic invertebrates, namely crustaceans in the early summer and oppossum shrimp in the fall. In the Vilyusk resevoir, diet overlap with pike forces burbot to broaden their diet breadth to include more benthic invertebrates (Kirillov 1988). In addition to fish and invertebrates, Bailey (1972) also found rocks, wood chips, plastic, and other inert materials in burbot stomachs, indicating that burbot feeding habits were somewhat indiscriminate.

Animal Foods: fish; insects; mollusks; aquatic or marine worms; aquatic crustaceans; zooplankton

Primary Diet: carnivore (Piscivore )

Comments: Young eat mainly immature aquatic insects, crayfish, molluscs, and other deepwater invertebrates. Larger individuals feed mostly on fishes (Becker 1983, Scott and Crossman 1973).

Burbot are top predators in their ecosystem, sometimes overlapping with similar top predators such as Esox or large salmonidae (Kirillov 1988).

esox lucius are known to prey on burbot where the two species coexist (Schwalme 1992). Osmerus eperlanus and perca flavescens prey on larval and juvenile individuals (Scott and Crossman 1973). Humans also exert predation pressure on burbot through commercial and sport fisheries (Cohen 1990; Kirillov 1988). In the Great Lakes, the sea lamprey, Petromyzon_marinus, is also known to prey on burbot (Smith 1971). Burbot rely on their cryptic habits and coloration to avoid predators.

Known Predators:

• northern pike (Esox_lucius)
• yellow perch (Perca_flavescens)
• smelt (Osmerus_eperlanus)
• sea lamprey (Petromyzon_marinus)
• humans (Homo_sapiens)

Anti-predator Adaptations: cryptic

Burbot are top predators in their ecosystem, sometimes overlapping with similar top predators such as pike or large salmonids (Kirillov 1988).

Northern pike are known to prey on burbot where the two species coexist (Schwalme 1992). Smelt and yellow perch prey on larval and juvenile individuals (Scott and Crossman 1973). Humans also exert predation pressure on burbot through commercial and sport fisheries (Cohen 1990; Kirillov 1988). In the Great Lakes, the sea lamprey, Petromyzon marinus, is also known to prey on burbot (Smith 1971). Burbot rely on their cryptic habits and coloration to avoid predators.

Known Predators:

• northern pike (Esox lucius)
• yellow perch (Perca flavescens)
• smelt (Osmerus eperlanus)
• sea lamprey (Petromyzon marinus)
• humans (Homo sapiens)

Anti-predator Adaptations: cryptic

Lota lota preys on:
Pallasea
Gammaracanthus
Myoxocephalus thompsonii
Etheostoma caeruleum

Based on studies in:
Finland (Lake or pond, Pelagic)

This list may not be complete but is based on published studies.

Enteric Redmouth Disease. Bacterial diseases

Burbot perceive chemical, tactile, visual, and acoustic stimuli, as do most fish. Though burbot and northern pike exhibit similar hunting strategies, burbot appear to rely less on sight than pike (Kahilainen and Lehtonen 2003).

Perception Channels: visual ; acoustic ; vibrations

Burbot perceive chemical, tactile, visual, and acoustic stimuli, as do most fish. Though burbot and northern pike exhibit similar hunting strategies, burbot appear to rely less on sight than pike (Kahilainen and Lehtonen 2003).

Perception Channels: visual ; acoustic ; vibrations

Burbot eggs hatch in the spring between April and June depending on location (Bjorn 1940; Cohen 1990). Time to hatching is dependent on temperature as well as the particular population and eggs usually take between 30 and 70 days to hatch (MacCrimmon 1959; Bjorn 1940). In four weeks larval burbot increase in length from less than 1 cm to over 2 cm (Ghan and Sprules 1993). Burbot in Lake Superior exhibited very fast growth rates during the first two growing seasons, attaining 42% of total length after 10 growing seasons (Bailey 1972).

In the Vilyuy River Basin, Siberia, burbot attain sexual maturity in their 7th or 8th year, with males usually maturing 1 year before females (Kirillov 1988). In Lake Superior, burbot as young as one year old were sexually mature (Bailey 1972). Though sexually mature specimens were found for both sexes in year 1 and older age classes, there was a higher proportion of sexually mature males until year 5 when all specimens of both sexes were sexually mature (Bailey 1972). Activity of burbot increases in autumn as energy reserves are concentrated on the growth and development of gonads for the winter spawning season (Kirillov 1988). Maturation of the gonads in both sexes occurs about 4 months after the fall peak in nutritional reserves (Pulliainen and Korhonen 1990).

There appears to be individual movements into spawning areas with the males arriving first at spawning areas (Ref. 27547). It occurs at night, with spawners forming a great globular mass, each pushing toward the center (Ref. 28694), or at least milling around close together (Ref. 28697), releasing eggs or sperm. Observed to make postspawning runs upriver, apparently for feeding (Ref. 28697). Eggs hatch after 40-70 days. After about 2 months, juveniles are benthic, grow rapidly, reach about 8 cm SL within first year. (Ref. 59043).

Burbot eggs hatch in the spring between April and June depending on location (Bjorn 1940; Cohen 1990). Time to hatching is dependent on temperature as well as the particular population and eggs usually take between 30 and 70 days to hatch (MacCrimmon 1959; Bjorn 1940). In four weeks larval burbot increase in length from less than 1 cm to over 2 cm (Ghan and Sprules 1993). Burbot in Lake Superior exhibited very fast growth rates during the first two growing seasons, attaining 42% of total length after 10 growing seasons (Bailey 1972).

In the Vilyuy River Basin, Siberia, burbot attain sexual maturity in their 7th or 8th year, with males usually maturing 1 year before females (Kirillov 1988). In Lake Superior, burbot as young as one year old were sexually mature (Bailey 1972). Though sexually mature specimens were found for both sexes in year 1 and older age classes, there was a higher proportion of sexually mature males until year 5 when all specimens of both sexes were sexually mature (Bailey 1972). Activity of burbot increases in autumn as energy reserves are concentrated on the growth and development of gonads for the winter spawning season (Kirillov 1988). Maturation of the gonads in both sexes occurs about 4 months after the fall peak in nutritional reserves (Pulliainen and Korhonen 1990).

The lifespan of burbot has been known to be as high as 20 years, though studies of natural populations rarely see individuals exceeding 10 to 12 years of age (Cohen 1990; Kirillov 1988; Bailey 1972). Incidence of older and larger individuals in nearctic regions may exceed that of older individuals in palearctic regions due to the absence of an established fishery, sport or otherwise, in North America where one thrives in Eurasia (Kirillov 1988).

Range lifespan

Status: wild: 20 (high) years.

Typical lifespan

Status: wild: 1 to 12 years.

The lifespan of burbot has been known to be as high as 20 years, though studies of natural populations rarely see individuals exceeding 10 to 12 years of age (Cohen 1990; Kirillov 1988; Bailey 1972). Incidence of older and larger individuals in nearctic regions may exceed that of older individuals in palearctic regions due to the absence of an established fishery, sport or otherwise, in North America where one thrives in Eurasia (Kirillov 1988).

Range lifespan

Status: wild: 20 (high) years.

Typical lifespan

Status: wild: 1 to 12 years.

Burbot breed once per year in the winter, migrating to shallow water or to a smaller stream to spawn (Cohen 1990). Burbot move to spawning areas individually and males tend to arrive before females (Morrow 1980). Spawning occurs during the night when individuals form a globular mass, each fish pushing toward the center and releasing eggs or sperm (MacCrimmon 1959; Cahn 1936). Postspawning runs upstream have been observed, most likely for feeding (MacCrimmon 1959).

Mating System: polygynandrous (promiscuous)

Burbot are potamodromous, migrating up tributaries or smaller stream reaches to spawn (Cohen 1990). They spawn in winter, laying their eggs in shallow water to hatch during the spring (Kirillov 1988). Fecundity varies geographically from slightly above 100,000 in specimens from Wyoming to over 3 million elsewhere in their range (Bailey 1972). Average fecundity ranges from 700,000 to 800,000 eggs (Kirillov 1988; Bailey 1972). Eggs are yellow, amber, or orange in color, spherical, and rest on the substrate (Koli 1990; Bjorn 1940). Eggs usually hatch in two to four months.

Burbot may take several years to become sexually mature. Present literature indicates a certain proportion of burbot populations fail to mature during each breeding season (Pulliainen and Korhonen 1990). Some studies have also suggested that burbot may take one or two years to restore nutritional reserves after a spawning event (Pulliainen and Korhonen 1990).

Breeding interval: Burbot spawn once yearly.

Breeding season: Burbot spawning occurs in the winter between December and March (varies geographically) but lasts no longer than one month for any one population.

Range number of offspring: 100000 to 3000000.

Average number of offspring: 700000-800000.

Range time to hatching: 2 to 4 months.

Range age at sexual or reproductive maturity (female): 1 to 8 years.

Average age at sexual or reproductive maturity (female): 6 years.

Range age at sexual or reproductive maturity (male): 1 to 8 years.

Average age at sexual or reproductive maturity (male): 3 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); broadcast (group) spawning; oviparous

Burbot are broadcast spawners and provide no parental care. Parental investment in burbot is characterized by an increased metabolic activity level and food consumption rates in the fall in order to contribute to the growth and maturation of gonads in both male and females over a four month period preceeding spawning events (Pulliainen and Kohonen 1990; Kirrilov 1988). It has been suggested that burbot may require one to two years to replenish their nurtritional reserves after each spawning event, but no further information on this topic was available (Pulliainen and Kohonen 1990).

Parental Investment: pre-fertilization (Provisioning)

Burbot breed once per year in the winter, migrating to shallow water or to a smaller stream to spawn (Cohen 1990). Burbot move to spawning areas individually and males tend to arrive before females (Morrow 1980). Spawning occurs during the night when individuals form a globular mass, each fish pushing toward the center and releasing eggs or sperm (MacCrimmon 1959; Cahn 1936). Postspawning runs upstream have been observed, most likely for feeding (MacCrimmon 1959).

Mating System: polygynandrous (promiscuous)

Burbot are potamodromous, migrating up tributaries or smaller stream reaches to spawn (Cohen 1990). They spawn in winter, laying their eggs in shallow water to hatch during the spring (Kirillov 1988). Fecundity varies geographically from slightly above 100,000 in specimens from Wyoming to over 3 million elsewhere in their range (Bailey 1972). Average fecundity ranges from 700,000 to 800,000 eggs (Kirillov 1988; Bailey 1972). Eggs are yellow, amber, or orange in color, spherical, and rest on the substrate (Koli 1990; Bjorn 1940). Eggs usually hatch in two to four months.

Burbot may take several years to become sexually mature. Present literature indicates a certain proportion of burbot populations fail to mature during each breeding season (Pulliainen and Korhonen 1990). Some studies have also suggested that burbot may take one or two years to restore nutritional reserves after a spawning event (Pulliainen and Korhonen 1990).

Breeding interval: Burbot spawn once yearly.

Breeding season: Burbot spawning occurs in the winter between December and March (varies geographically) but lasts no longer than one month for any one population.

Range number of offspring: 100000 to 3000000.

Average number of offspring: 700000-800000.

Range time to hatching: 2 to 4 months.

Range age at sexual or reproductive maturity (female): 1 to 8 years.

Average age at sexual or reproductive maturity (female): 6 years.

Range age at sexual or reproductive maturity (male): 1 to 8 years.

Average age at sexual or reproductive maturity (male): 3 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); broadcast (group) spawning; oviparous

Burbot are broadcast spawners and provide no parental care. Parental investment in burbot is characterized by an increased metabolic activity level and food consumption rates in the fall in order to contribute to the growth and maturation of gonads in both male and females over a four month period preceeding spawning events (Pulliainen and Kohonen 1990; Kirrilov 1988). It has been suggested that burbot may require one to two years to replenish their nurtritional reserves after each spawning event, but no further information on this topic was available (Pulliainen and Kohonen 1990).

Parental Investment: pre-fertilization (Provisioning)

Spawns mainly in winter in North America. Eggs hatch in about a month. Individuals spawn annually or in alternate years. Usually sexually mature in 3-4 years (males) or 4-5 years (females) (see USFWS 2003).

The following is a representative barcode sequence, the centroid of all available sequences for this species.


There are 32 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.


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Barcode of Life Data Systems (BOLDS) Stats
Public Records: 34
Specimens with Barcodes: 45
Species With Barcodes: 1

Burbot are near extinction in the Kootnai river in Idaho and British Columbia due to construction of the Libby dam in Idaho. Efforts to bring back the population are ongoing (Kootnai River Fisheries Investigation 2000). Burbot are stocked where commercial fisheries exist in Europe (Kirillov 1988).

IUCN Red List of Threatened Species: least concern

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

Burbot are near extinction in the Kootnai river in Idaho and British Columbia due to construction of the Libby dam in Idaho. Efforts to bring back the population are ongoing (Kootnai River Fisheries Investigation 2000). Burbot are stocked where commercial fisheries exist in Europe (Kirillov 1988).

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Population

Population Trend

Least Concern (LC)

Major Threats

Conservation Actions

There are no known negative effects of burbot on humans.

Burbot are an important commercial fishery in parts Eurasia where they are used as a source of oil, the flesh is eaten, and liver is sold smoked or canned (Kirillov 1988; Scott and Crossman 1973). Burbot are also processed into fish meal (Scott and Crossman 1973). Because of slow movements and nocturnal habits, little or no sport fishery exists in North America (Cohen 1990).

Positive Impacts: food ; body parts are source of valuable material

fisheries: commercial; aquaculture: experimental; gamefish: yes; aquarium: public aquariums

There are no known negative effects of burbot on humans.

Burbot are an important commercial fishery in parts Eurasia where they are used as a source of oil, the flesh is eaten, and liver is sold smoked or canned (Kirillov 1988; Scott and Crossman 1973). Burbot are also processed into fish meal (Scott and Crossman 1973). Because of slow movements and nocturnal habits, little or no sport fishery exists in North America (Cohen 1990).

Positive Impacts: food ; body parts are source of valuable material

Comments: The only freshwater member of the family (Nelson 1984).