Soft sculpin

Psychrolutes sigalutes

FAMILY

Psychrolutidae

TAXONOMY

Psychrolutes sigalutes Jordan and Starks, 1895, Puget Sound near Port Orchard, Washington, United States. Species is listed as Gilbertidia sigalutes in older species compendiums, and is listed as a member of the family Cottidae.

OTHER COMMON NAMES

None known.

PHYSICAL CHARACTERISTICS

The soft sculpin has flaccid skin in which the single dorsal fin seems embedded. The lateral line and head canal pores of adults are large and obvious, especially around the jaws and cheeks. Adults are dark brown or translucent beige. Adult males are much larger than females and often have scars over their large heads. Males can approach 3.5 in (9 cm) in length. The pelagic young have relatively larger eyes, no obvious pores, and are purple with orange pectoral fins.

DISTRIBUTION

Coastal waters from Puget Sound, Washington, to the Aleutian Islands, Alaska.

HABITAT

Larvae of the soft sculpin migrate to feed at the surface at dawn and dusk. Then as pelagic juveniles, they alternate between settling to soft bottom and migrating to the surface on dark nights when surface plankton is abundant. Females grow to 75% of mature body size while exploiting the plankton. Soft sculpins permanently settle during late spring and occupy deep crevices or recesses in multilayered rock rubble, usually on shorelines protected from wave surge.

BEHAVIOR

The male soft sculpin continues growing after settlement, whereas the female starts developing ripe ovaries. The male is highly territorial, rotating his body in a circle and stuttering his head to keep other males away from his territory. Head biting occurs among males.

FEEDING ECOLOGY AND DIET

Feeding is visual during early larval stages, then the pelagic juveniles switch to use of distant touch at night as the eyes become relatively smaller and the head canal pores enlarge. Adults in crevices use distant touch to detect crustacean prey like amphipods. Adults cannibalize young soft sculpins that enter their territory.

REPRODUCTIVE BIOLOGY

The male soft sculpin attracts a harem of several females and courts them in synchrony prior to copulating with each female in sequence. Females simultaneously lay a group, monolayer egg mass on the underside of a rock surface. The females tend the eggs communally, the fanning behavior of one female stimulating similar behavior in adjacent females. The male remains to one side and guards the nest site against other fishes or invertebrates. At hatching, the females suck larvae from the egg shells, swim away from the nest crevice, and spit the larvae toward the surface.

CONSERVATION STATUS

Not listed by the IUCN. Detection of soft sculpins tends to occur rarely. It is doubtful whether human activities directly affect this species.

SIGNIFICANCE TO HUMANS

None known.