Environment: milieu / climate zone / depth range / distribution range
Freshwater; demersal. Boreal; 4°C - 14°C (Ref. 2059); 72°N - 55°N
North America: Alaska from Colville River delta south to central Alaska Peninsula near Chignik; upstream in Yukon-Tanana drainage to near Fairbanks. Also Bering Sea islands and northeastern Siberia, Russia.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 33.0 cm TL male/unsexed; (Ref. 5723); common length : 10.8 cm TL male/unsexed; (Ref. 12193); max. published weight: 366.00 g (Ref. 28675); max. reported age: 8 years (Ref. 12193)
soft rays: 12 - 16;
Vertebrae: 40 - 42. Identified by its short, flattened snout, the rearward location of the dorsal and anal fins, the presence of about 33 rays in the pectorals, and the presence of a pelvic fin that has only 3 rays (Ref. 27547). Gill rakers short; lateral line with minute pores: 76 to 100 scales in midlateral series (Ref. 27547). Dorsal located far back on body; anal more or less under dorsal; edge of pectorals rounded; pelvic fins very small and located just before anus; caudal broad and rounded (Ref. 27547). Dark green or brown above and on upper sides, pale below with dark speckles; four to six irregular dark bars or blotches on sides; fins have dark brownish specklings; dorsal, anal and caudal fins with pale margin, which are pink to red in spawning adults (Ref. 27547).
Facultative air-breathing (Ref. 126274); Usually found in heavily vegetated swamps and ponds; occasionally in medium to large rivers and lakes with abundant vegetation (Ref. 5723). Migrations appear to be limited to inshore or upstream movements to spawning grounds in the spring and (presumably) reverse migrations to deeper water in the fall (Ref. 27547). Oviparous, batch spawner (Ref. 205). Known for their tolerance to cold water: survives exposures to -20°C for up to 40 minutes, and can survive for a few days after complete freezing of parts of the body, even the head (Ref. 28673, 28674). Uses its esophagus as auxiliary breathing organ (Ref. 27797).
Upstream movement appears to coincide with a rise of water temperature to 10° to 15°C (Ref. 3829). Females normally contain two sets of eggs, the smaller group presumably being the set which will be spawned the following year. Females deposit 40 to 300 eggs, the number increasing with size. A female probably spawns over a period of several days, possibly longer, with only a few eggs being extruded at each spawning act. (Ref. 27547).
Page, L.M. and B.M. Burr, 1991. A field guide to freshwater fishes of North America north of Mexico. Houghton Mifflin Company, Boston. 432 p. (Ref. 5723)
IUCN Red List Status (Ref. 126983)
Threat to humans
Fisheries: subsistence fisheries; aquarium: commercial
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82804
= 0.6329 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00891 (0.00410 - 0.01937), b=3.09 (2.89 - 3.29), in cm total length, based on LWR estimates for this species & (Sub)family-body (Ref. 93245
Trophic level (Ref. 69278
): 3.3 ±0.44 se; based on food items.
Resilience (Ref. 120179
): Medium, minimum population doubling time 1.4 - 4.4 years (tm=2-3; tmax=8; Fec=40-300).
Fishing Vulnerability (Ref. 59153
): Low vulnerability (23 of 100).