Feeding Interactions between Fishes in a Coastal Ecosystem in the Southern Gulf of St. Lawrence, Atlantic Canada

Abstract

AbstractFor the period 1999–2003, diet composition, diet similarity, and major predator–prey interactions between the 15 most abundant demersal and pelagic fishes (N = 12,163 stomachs) were described for Northumberland Strait - a semienclosed, marine, coastal ecosystem. Of the five pelagic species, Rainbow Smelt Osmerus mordax ate benthic prey (shrimps and polychaetes), Atlantic Herring Clupea harengus and American Shad Alosa sapidissima consumed small copepods and crab zoea, and Atlantic Mackerel Scomber scombrus and Alewife A. pseudoharengus ate small copepods and moderate amounts of benthic prey and small fishes. Three demersal species were strongly piscivorous but with minimal diet overlap: Sea Raven Hemitripterus americanus consumed small benthic fishes (especially flounders); Winter Skate Leucoraja ocellatus consumed sand lance (Ammodytes sp.) and Rainbow Smelt; and White Hake Urophycis tenuis consumed Atlantic Herring and Atlantic Mackerel. Cluster analysis revealed seven feeding guilds of which fo...