Male mottled sculpin use courtship movements to attract females to their nest cavities. They shake their heads, raise their gills, and undulate their bodies to get the attention of females. The color and band on their dorsal fin is probably also involved in courtship, as it only appears during the breeding season. When a female approaches, the male will bite her cheek, side, fins, or tail or else grab her by the head and pull her into the nest cavity. Once inside the nest cavity, the female turns upside down so that she can release her eggs onto the cavity ceiling. The male accompanies the female into the cavity and arranges himself next to her. The male's head and fins then become jet black and his body becomes pale. The male blocks the nest cavity entrance for several days so that the female remains inside. Males eventually attract several (average 3.3) females into their nests to mate.
Mating System: polygynous
Male mottled sculpin begin to defend nest cavities in the spring. Nest cavities are areas beneath rocks or other debris at depths of about 22 cm and in areas with enough water flow to prevent silt build up. Nest entrances usually face upstream. Males attract females to their nests, where the females remain for a few days and lay their eggs. Males then remain in the nest cavities until the eggs hatch and the young fish leave the nest a few weeks after hatching. In Wisconsin, males are in nests from April to the end of May. Females are recorded to have from 111 to 635 (average 328) eggs at a time. Eggs hatch in about 17 days and young depart from the nest about 14 days after that. Sexual maturity is reached at adult sizes of 59.2 mm in males and 53.1 mm in females, sizes that can be reached within a year of hatching.
Breeding interval: Mottled sculpin breed once yearly.
Breeding season: Mottled sculpin breed in the spring. In Wisconsin breeding occurs from early April through May.
Range number of offspring: 111 to 635.
Average number of offspring: 328.
Average time to hatching: 17 days.
Average time to independence: 14 days.
Average age at sexual or reproductive maturity (female): 1 years.
Average age at sexual or reproductive maturity (male): 1 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous
Male mottled sculpins guard clusters of eggs that have been laid by different females. They protect the eggs from predators until they hatch.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Male)
- Becker, G. 1983. Fishes of Wisconsin. Madison, Wisconsin: The University of Wisconsin Press.
- Froese, R. 2008. "fishbase.org" (On-line). Accessed December 10, 2008 at http://fishbase.sinica.edu.tw/summary/SpeciesSummary.php?id=4065.
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