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)