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 ; tactile ; acoustic ; vibrations ; chemical
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
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 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
Burbot are top predators in their ecosystem, sometimes overlapping with similar top predators such as pike or large salmonids (Kirillov 1988).
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 )
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
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
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 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) cm3.O2/g/hr.
Average basal metabolic rate: 73.9 cm3.O2/g/hr.
Other Physical Features: ectothermic ; bilateral symmetry
Sexual Dimorphism: sexes alike
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:
Anti-predator Adaptations: cryptic
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 gestation period: 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)
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.
The burbot (Lota lota) is the only gadiform (cod-like) freshwater fish. It is also known as bubbot,[2] mariah,[3] loche, cusk,[4] freshwater cod,[5] freshwater ling, freshwater cusk, the lawyer, coney-fish, lingcod,[6] and eelpout. The species is closely related to the marine common ling and the cusk. It is the only member of the genus Lota. For some time of the year, the burbot lives under ice, and it requires frigid temperatures to breed.[7]
The name burbot comes from the Latin word barba, meaning beard, referring to its single chin whisker, or barbel.[8] Its generic and specific names, Lota lota, comes from the old French[9] lotte fish, which is also named "barbot" in Old French.
With an appearance like a cross between a catfish and an eel, the burbot has a serpent-like body, but is easily distinguished by a single barbel on the chin.[8] The body is elongated and laterally compressed, with a flattened head and single, tube-like projection for each nostril. The mouth is wide, with both upper and lower jaws having many small teeth. Burbot have two soft dorsal fins, with the first being low and short, and the second being much longer. The anal fin is low and almost as long as the dorsal fin. The caudal fin is rounded, the pectoral fins are fan-shaped, and pelvic fins are narrow with an elongated second fin ray. Having such small fins relative to body size indicates a benthic lifestyle with low swimming endurance, unable to withstand strong currents.
Burbot have circumpolar distribution above 40°N. Populations are continuous from France across Europe and Asia to the Bering Strait. In North America, burbot range from the Seward Peninsula in Alaska to New Brunswick along the Atlantic Coast. Burbot are most common in streams and lakes of North America and Europe. They are fairly common in Lake Erie, but are also found in the other Great Lakes.[10] Recent genetic analysis suggests the geographic pattern of burbot may indicate multiple species or subspecies, making this single taxon somewhat misleading.[11]
In the United Kingdom, the burbot is possibly extinct. The last recorded capture was a specimen weighing 0.48 kg (1.1 lb), in July 1970, by Stephen Mackinder, from the Cut-off Channel or the Great Ouse Relief Channel, at Denver, Norfolk.[12] In October 1970, it was described in the Guinness Book of Records as the "rarest British fish" which was "almost extinct", so it had been "agreed that no record for this species should be published, at least until 1974, in the interests of conservation".[13] The burbot may still survive in the UK. The counties of Cambridgeshire, Norfolk[14] and Yorkshire (particularly the River Derwent or Yorkshire Ouse) seem to be the strongest candidates for areas in which the species might yet survive. Plans to reintroduce this freshwater member of the cod family back into British waters are under investigation.[5]
Burbot live in large, cold rivers, lakes, and reservoirs, primarily preferring freshwater habitats, but able to thrive in brackish environments for spawning. During the summer, they are typically found in the colder water below the thermocline. In Lake Superior, burbot can live at depths below 300 m (980 ft).[11] As benthic fish, they tolerate an array of substrate types, including mud, sand, rubble, boulder, silt, and gravel, for feeding.[15] Adults construct extensive burrows in the substrate for shelter during the day. Burbot are active crepuscular hunters.[11] Burbot populations are adfluvial during the winter, and they migrate to near-shore reefs and shoals to spawn,[11] preferring spawning grounds of sand or gravel.[15]
Burbot reach sexual maturity at between four and seven years of age.[16] Spawning season typically occurs between December and March, often under ice at extremely low temperatures ranging between 1 and 4 °C. During a relatively short season lasting from two to three weeks, burbot spawn multiple times, but not every year.[11]
As broadcast spawners, burbot do not have an explicit nesting site, but rather release eggs and sperm into the water column to drift and settle. When spawning, many male burbot gather around one or two females, forming a spawning ball. Writhing in the open water, males and females simultaneously release sperm and eggs. Depending on water temperatures, the incubation period of the eggs lasts from 30 to 128 days. Fertilized eggs then drift until they settle into cracks and voids in the substrate.[16]
Depending on body size, female burbot fecundity ranges from 63,000 to 3,478,000 eggs for each clutch.[11] Rate of growth, longevity, and age of sexual maturity of burbot are strongly correlated with water temperature; large, older individuals produce more eggs than small, younger individuals. Eggs are round with a large oil globule, about 1 mm (0.039 in) in diameter and have an optimal incubation range between 1 and 7 °C (34 and 45 °F).[11]
Newly hatched burbot larvae are pelagic, passively drifting in the open water. Habitats near 4 °C (39 °F) are optimal for burbot and they prefer water temperatures of 12 °C (54 °F) and lower.[16] By night, juveniles are active, taking shelter during the day under rocks and other debris. Growing rapidly in their first year, burbot reach between 11 and 12 cm (4.3 and 4.7 in) in total length by late fall.[11] During their second year of life, burbot on average grow another 10 cm (3.9 in).[17]
Burbot transition from pelagic habitats to benthic environments as they reach adulthood, around five years old. Average length of burbot by maturity is about 40 cm (16 in), with slight sexual dimorphism.[17] Maximum lengths range between 30 and 120 cm (12 and 47 in), and weights range from 1.0 to 12 kg (2.2 to 26.5 lb).
At the larval stage, month-old burbot begin exogenous feeding, consuming food through the mouth and digesting in the intestines. Burbot at the larval stage and into the juvenile stage feed on invertebrates based on size. Under 1 cm (0.39 in), burbot eat copepods and cladocerans, and above 1–2 cm (0.39–0.79 in), zooplankton and amphipods. As adults, they are primarily piscivores, preying on lamprey, whitefish, grayling, young northern pike, suckers, stickleback, trout, and perch.[11] At times, burbot also eat insects and other macroinvertebrates, and have been known to eat frogs, snakes, and birds. Having such a wide diet is also correlated to their tendency to bite lures, making them very easy to catch. Burbot are preyed upon by northern pike, muskellunge, and some lamprey species.
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A book written in 1590 in England notes that burbot were so common that they were used to feed hogs.[18]
The burbot is edible. In Finland, its roe and liver are highly regarded as delicacies, as is the fish itself. An annual spearfishing tournament is held near Roblin, Manitoba. One of the highlights of the tournament is the fish fry, where the day's catch is served deep-fried. When cooked, burbot meat tastes very similar to American lobster, leading to the burbot's nickname of "poor man's lobster".
In the 1920s, Minnesota druggist Theodore "Ted" H. Rowell and his father, Joseph Rowell, a commercial fisherman on Lake of the Woods, were using the burbot as feed for the foxes on Joe's blue fox farm. They discovered the burbot contained something that improved the quality of the foxes' furs; this was confirmed by the fur buyers, who commented that these furs were superior to other furs they were seeing. Ted Rowell felt it was something in the burbot, so he extracted some oil and sent it away to be assayed. The result of the assay was that the liver of the burbot has three to four times the potency in vitamin D, and four to 10 times in vitamin A, than "good grades" of cod-liver oil. Their vitamin content varies from lake to lake, where their diets may have some variation. Additionally, liver makes up about 10% of the fish's total body weight, and its liver is six times the size of those of freshwater fish of comparable size. The oil is lower in viscosity, and more rapidly digested and assimilated than most other fish-liver oils. Rowell went on to found the Burbot Liver Products Company, which later became Rowell Laboratories, Inc.
The IGFA recognizes the world-record burbot as caught on Lake Diefenbaker, Saskatchewan, Canada, by Sean Konrad on 27 March 2010. The fish weighed 25 lb 2 oz (11.4 kg).[19]
The burbot is a tenacious predator, which sometimes attacks other fish of almost the same size, and as such, can be a nuisance fish in waters where it is not native. Recent discoveries of burbot in the Green River at Flaming Gorge Reservoir in Utah have concerned wildlife biologists, who fear the burbot could decimate the sport-fish population in what is recognized as one of the world's top brown trout fisheries, because it often feeds on the eggs of other fish in the lake, such as sockeye salmon. The Utah Division of Fish and Game has instituted a "no release" "catch and kill" regulation for the burbot in Utah waterways.[20] However, the regulations have been found to be largely unenforceable.
The town of Walker, Minnesota, holds an International Eelpout Festival every winter on Leech Lake.[21] The festival received national attention on 4 March 2011, when a correspondent from The Tonight Show with Jay Leno did a segment on the event.
Burbot populations are difficult to study, due to their deep habitats and reproduction under ice. Although burbot global distribution is widespread and abundant, many populations have been threatened or extirpated. Ichthyologists and taxonomists are strongly advising to look into the old taxonomical due to new genetic insights there are two species of burbot: the European burbot (Lota lota) and the North-American burbot (Lota maculosa).[22] As the burbot lacks popularity in commercial fishing, many regions do not even consider management plans. Pollution and habitat change, such as river damming, appear to be the primary causes for riverine burbot population declines, while pollution and the adverse effects of invasive species have the greatest influence on lacustrine populations. Management of burbot is on low priority, being nonexistent in some regions.[23]
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{{cite web}}: CS1 maint: archived copy as title (link) 
Burbot, Lota lota The burbot (Lota lota) is the only gadiform (cod-like) freshwater fish. It is also known as bubbot, mariah, loche, cusk, freshwater cod, freshwater ling, freshwater cusk, the lawyer, coney-fish, lingcod, and eelpout. The species is closely related to the marine common ling and the cusk. It is the only member of the genus Lota. For some time of the year, the burbot lives under ice, and it requires frigid temperatures to breed.
