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Figure 2. — Diagrammatic representation of prey of 15 gadiform 

 fishes from five geographic areas in the northwest Atlantic for both 

 spring and autumn bottom trawl survey cruises, 19fi9-72. Data are 

 expressed as percentage weight. 



Atlantic cod, Gadus morhua. — Atlantic cod preyed 

 most heavily on fish (64.0%). Clupeidae (27.4%) were the 

 most important prey, with the Atlantic herring, Clupea 

 harengus (IG.T'it ), being the largest single contributor to 

 the diet. The Gadidae made up 3.7% of the diet while the 

 Scombridae, represented exclusively by the Atlantic 

 mackerel. Scomber scombrus, composed 3.1% of the diet. 

 The Scorpaenidae contributed 3.2% to the diet, of which 

 2.6% was identified as the redfish, Sebastes marinus. 

 After fish, the crustaceans were the next most important 

 prey group, making up 20.7% of the diet by weight. Deca- 

 pods were the most important crustaceans totaling 16.6% 

 of the diet. The Cancridae, represented by both species 

 of Cancer, i.e., C. borealis (l.S"";) and C. irroratus (1.4%), 

 constituted a major part of the decapod prey totaling 

 4.7% of the diet. Pandalid shrimp (2.9%), particularly 

 Dichelopandalis leptocerus (1.3%), and the toad crabs 

 (2.1%) (family Majidae) of the genus Hyas also ac- 

 counted for part of the decapod prey. Other phyla played 

 a less important role. MoUusca composed only 7.6% of 

 the prey with the pelecypods Placopecten (2.9%) and 

 Pecten (1.2%) contributing the major fraction. Scallops 

 were important only on Georges Bank and may repre- 

 sent the remains of scallops discarded by fishermen 

 which were then preyed upon by cod. A similar situation 

 was observed for Georges Bank haddock by Wigley 



(1956). Polychaetes and echinoderms composed an even 

 smaller percentage of the diet, 1.3 and 1.2%, respec- 

 tively. 



Pollock, Pollachius virens. — Almost one-half of the 

 pollock's diet was fish (47.0%). The majority were clupe- 

 ids (19.2%) which were identified as Atlantic herring 

 (14.3%). Gadids (1.4'r) were also preyed on, especially 

 silver hake (1.2%), and in one instance a juvenile pollock 

 was identified as part of the stomach contents. A small 

 percentage of the stomach contents was made up of the 

 scorpaenid Sebastes marinus (1.5%). "Other Pisces" 

 (24.9%) accounted for over half the fish, and in this cate- 

 gory eels (5.7%), lanternfish (2.0%), and the American 

 sand lance, Ammodytes americanus (0.1%), could be 

 identified. The remaining half of the diet consisted ex- 

 clusively of crustaceans (SO.SSc). Euphausiids (35.3%) 

 made up the majority of the Crustacea, with Meganyc- 

 tiphanes norvegica contributing 26.5% of the diet by 

 weight. Other species of euphausiids, such as Thysano- 

 essa inermis, T. longicaudata, and Euphausia krohnii, 

 were also identified in the stomach contents, but each of 

 these species contributed <1% to the total weight of the 

 prey consumed. Pandalid shrimp (2.5%) of the genera 

 Pandalus (1.8';) and Dichelopandalus (0.5%) were of 

 secondary importance, while Pasiphaea multidentata 

 (10.0%), a pelagic shrimp, listed under "Other Deca- 

 poda," was of major significance. Annelids (poly- 

 chaetes), molluscs, echinoderms, and other phyla con- 

 tributed only 1% of the total diet. 



Silver hake, Merluccius bilinearis. — The major pro- 

 portion of the silver hake's diet was fish (70.9%). These 

 hake preyed heavily on Atlantic mackerel (18.9%) and on 

 clupeids (14.6%) such as the Atlantic herring (10.4%) 

 and the alewife, Alosa pseudoharengus (4.2%). Silver 

 hake were also cannibalistic; 3.4% of the Gadidae (7.1%) 

 were silver hake. A large part of the fish could not be 

 identified due to their state of digestion. Consequently, 

 30.1% of the prey was included under "Other Pisces." 

 However, two groups in this category that could be 

 recognized were the butterfish, Peprilus triacanthus 

 (1.5%), and the lanternfish (family Myctophidae) 

 (1.1%). Crustaceans formed the remaining bulk of the 

 diet, 25.0%. Euphausiids (12.6%), such as Meganycti- 

 phanes norvegica (7.4%), were the single most important 

 crustaceans, but the pandalid shrimp, Dichelopandalus 

 leptocerus (3.2%), was also of some importance. Other 

 crustaceans which contributed to the diet were the two 

 caridean shrimp: Crangon septemspinosa (1.4%) and 

 Pasiphaea (2.0%). The only molluscs of any note were the 

 cephalopods (2.2%), such as the squid Loligo (1.5%). 



White hake, Urophycis tenuis. — White hake preyed 

 heavily on fish (78.2%). The clupeids (12.5%) were the 

 single most important group, with Atlantic herring mak- 

 ing up 4.8% of the total diet. Gadids (10.7%) were also 

 important, with silver hake (3.0%), red hake (0.8%), 

 Atlantic cod (0.5%), haddock (0.5%), longfin hake 

 (0.3%), and white hake (0.2%) all having been identified 



