Use of the lateral line for feeding in two Lake Baikal sculpins

Batrachocottus baicalensis, endemic to Lake Baikal, Russia, has wider lateral line canals than Paracottus kneri, which also inhabits Siberian streams. In quiet water B. baicalensis responded to amphipods at a greater distance than did P. kneri. Batrachocottus baicalensis also moves less often from search positions than does P. kneri. Fish responded to faster moving prey at a greater distance than slower prey. They also responded to a greater distance to prey moving more parallel to the fish's body surface. In an artificial stream B. baicalensis responded only to prey that touched them whilst P. kneri responded to both swimming prey and prey that contacted them. It is argued that B. baicalensis is primarily an ambush predator that is a habitat specialist and P. kneri is a cruising predator that visits many habitats.