Burbot

Marbled; base color varies from olive-green to yellowish or dark brown with dark, irregular spots; ventral side whitish to grey.

A single long barbel on the center of the chin; two dorsal fins, the first being short and the second very long; long anal fin; very small cycloid scales deeply embedded in the mucus layer.

Wels catfish (Silurus glanis) - which has multiple barbels and lacks a second dorsal fin; European eel (Anguilla anguilla) - lacks pelvic fins and a divided dorsal fin.

Minimal; females are recognizable by their girth during the spawning season and often reach larger body sizes than males.

Bream zone to ruffe-flounder zone; also found in the trout zone (upper reaches) and in deep, cool lakes (e.g., Lake Constance, Lake Baikal).

Benthic (bottom-dwelling); stays hidden during the day in caves, under roots, or stones.

Prefers moderately flowing to standing waters; avoids extremely strong currents but requires oxygen-rich water.

Gravel, stones, sand; structures such as deadwood or riprap are essential as shelter.

High; the species is sensitive to oxygen depletion, especially with rising water temperatures in summer.

Performs upstream migrations to shallower areas or suitable tributaries during the spawning season in winter.

Gravel, sand, or stones; eggs are broadcast over the substrate and sink into the interstitial spaces.

Initially pelagic lifestyle (open water) after hatching, transitioning to a benthic lifestyle on the water bottom after several weeks.

None; eggs are broadcast in the open water over the substrate without nest building or guarding.

Carnivorous; predatory, becoming a specialized piscivore with increasing age.

Zooplankton, insect larvae (e.g., Chironomidae, Ephemeroptera), small crustaceans (Gammarus).

Fish (e.g., ruffe, gudgeon, bullhead), fish eggs, larger invertebrates such as crayfish.

Nocturnal search and ambush predator; intensively uses the sense of smell and the lateral line organ to locate prey in the dark.

Predominantly solitary; however, forms dense groups (so-called spawning balls) during the spawning season.

Important predator in cool water systems; occupies the niche of the bottom-oriented predatory fish, particularly active in winter.

Northern pike, Wels catfish, European otter, cormorant; juveniles are preyed upon by numerous predatory fish species.

European eel (food competition on the water bottom), ruffe and bullhead (competition for shelter and food among juveniles).

Infestation by trematodes (e.g., Diplostomum), nematodes, and acanthocephalans is frequently documented.

Indicator for good water quality (oligosaprobic to beta-mesosaprobic), cool water temperatures, and ecological connectivity of watercourses.

Subject to fishery laws; legal closed seasons and minimum sizes are regulated by state/regional laws (e.g., in Bavaria, Saxony).

Regionally variable, usually during the main spawning season (e.g., Nov 1st to Feb 28th or Dec 1st to Feb 28th).

Valued food fish with firm, white flesh; the large liver is historically considered a delicacy; locally significant for inland fisheries.

River engineering and loss of spawning habitats; interruption of migration routes by barriers; climate warming (increase in summer temperatures).

Often declining or threatened in Central Europe (Red List Germany: V - Near Threatened, regionally highly endangered); populations often supported by stocking.

Restoration of connectivity (fish ladders); renaturation of riparian zones and spawning substrates; targeted stocking programs to support populations.