Comparative life histories and microhabitat use in three sympatric sculpins (Cottidae:Cottus) in northeastern California

Synopsis

Life histories of three sculpins endemic to the Pit River system, northeastern California, are detailed.Cottus pitensis is widely distributed throughout the drainage. This species is typically found in rapidly flowing, shallow water on coarse substrate. It grows to a large size, >100 mm, and lives to 5 years. Spawning occurs annually, in early spring. Fecundity is relatively low, <320 oocytes.Cottus asperrimus is restricted to a large population in Fall River and smaller concentrations in Hat Creek and Pit River. It is a relatively small fish, <80 mm, and lives to 5 years. It occurs in deep, slow-moving, often spring-fed streams, typically on fine substrates. Spawning lasts from autumn to early spring. Males establish nests on hard substrates and guard several clutches of eggs. Fecundity ranges from 140–580 oocytes.Cottus klamathensis macrops is relatively rare in the drainage. The largest concentration is in the Hat Creek system, smaller populations exist in Fall River and Pit River. This sculpin is found on coarse substrate, often where aquatic vegetation is abundant. It is typically found in slow, relatively shallow water. It grows to >100mm and lives to 5 years. Males guard eggs during the short spawning season beginning in late winter. Fecundity in this species reaches a maximum of 650 oocytes. Life history strategies vary within the genus, yet the life histories of these sculpins are more similar to each other than they are to many of their congeners. This within-group similarity may have resulted from exposure of all three species to similar environmental pressures. This is predicted by life-history theory.