Comparative biology of the sculpins of Lake Superior

The slimy sculpin (Cottus cognatus), spoonhead sculpin (Cottus ricei), and deepwater sculpin (Myoxocephalus thompsoni) are abundant fishes in Lake Superior. Slimy and spoonhead sculpins occupy a zone from near shore to depths of 210 m but are generally most abundant in waters 50 to 90 m deep. Deepwater sculpins are found in waters from 15 to 407 m deep and are most abundant at depths greater than 70 m. All three species of sculpins eat mainly burrowing amphipods (Pontoporeia affinis) although deepwater sculpins also eat substantial quantities of opossum shrimp (Mysis relicta). The three sculpins grow at similar rates. Among the fishes aged, the maximum age of slimy sculpins was 5 years, compared with 6 years for spoonhead sculpins, and 7 years for deepwater sculpins. Indirect evidence indicates that slimy and spoonhead sculpins spawn in the spring, and deepwater sculpins spawn in midwinter.