Scientific Name
Gasterosteus aculeatus aculeatus
Common Name
Three-spined stickleback
Biology
Adults occur in fresh waters, estuaries and coastal seas (Ref. 4119). Anadromous, with numerous non-anadromous populations in brackish or pure freshwater, rarely in marine waters. In the sea, confined to coastal waters. In freshwater, adults prefer to live in small stream but may occur in a variety of habitats including lakes and large rivers (Ref. 59043). Inhabit shallow vegetated areas, usually over mud or sand (Ref. 5723). Form schools. Young associated with drifting seaweed (Ref. 12114, 12115). Juveniles move to the sea (anadromous populations) or to deeper, larger water bodies (freshwater populations) in July-August, forming large feeding schools (Ref. 59043). Feed on worms, crustaceans, larvae and adult aquatic insects, drowned aerial insects, and small fishes; has also been reported to feed on their own fry and eggs (Ref. 1998). Eggs are found in