FISHERY BULLETIN: VOL. 82. NO. 1 



These two length groups were chosen because the 

 food consumption of fish < 1 yr old (4- 1 5 cm FL) dif- 

 fers substantially from the food consumption of older 

 fish (evident from Figure 2). In addition, too few fish 

 outside these length ranges were sampled to warrant 

 inclusion in any of the calculations dealing with com- 

 parisons between data sets. An analysis of variance 

 (one way) was used to test the observed differences 

 among sample means (e.g., between geographic 

 areas). 



RESULTS 



The contents of 2,622 silver hake stomachs, of 

 which 803 (30.4%) were empty, were analyzed. Fish 

 sampled averaged 20 cm FL and had, including the 

 empty ones, a mean stomach content weight of 1.5 g. 

 Sources of potential variation in the data presented 

 below include size, sex, and maturity stage offish, as 

 well as the time of day, area, year, season, bottom 

 depth, and temperature when or where the fish were 

 caught. Each variable considered in this analysis is 

 treated separately, i.e., the data were pooled over 

 other variables with no attempt to determine the 

 possible confounding effects of different variables on 

 the results. Dietary trends noted within each par- 

 ticular variable examined should be considered only 

 as preliminary observations. 



Composition of the Diet 



Overall, in terms of percentage weight, the diet of 

 silver hake consists almost entirely of fish (80.0%), 

 crustaceans (10.2%), and squid (9.2%), as can be 

 seen in Table 2 . The importance of crustaceans to the 

 diet is overshadowed by the fish portion because 

 large silver hake eat heavier meals consisting pri- 

 marily of fish. However, Table 2 is useful because it 

 serves as a composite list of the prey types commonly 

 found in the stomachs of silver hake. Fish such as 

 silver hake, Merluccius bilinearis; Atlantic mackerel, 

 Scomber scombrus; butterfish, Peprilus triacanthus; 

 herring (Clupeidae); American sand lance, Am- 

 modytes americanus; scup, Stenotomus chrysops; At- 

 lantic saury, Scomberesox saurus; and longfin hake, 

 Phycis chesteri, each make up >0.1% of the stomach 

 contents. The "Other Pisces" category, most of 

 which could not be identified, accounts for a substan- 

 tial portion (52.07c) of the "Pisces" group. Fishes 

 which could be identified within this category (all 

 contributed <0.1% to the diet) include summer 

 flounder, Paralichthys dentatus; redfish, Sebastes 

 marinus; codfishes (Gadidae); and flatfishes (Pleuro- 

 nectiformes). 



Crustacea in the diet is represented principally by 

 euphausiids (mostly Meganyctiphanes norvegica, 3.7%, 

 and Euphausia, <0.1%) and decapods such as the 

 Crangonidae (mainly Crangon septemspinosa, 1.4%, 

 and Sclerocrangon boreas, <0.1%), Pandalidae (al- 

 most exclusively Dichelopandalus leptocerus, 2.0%, 

 although some Pandalus borealis, <0.1%, was also 

 found), Pasiphaeidae (only Pasiphaea multidentata, 

 0.1%), and other unidentified decapods (0.4%) which 

 were mostly shrimp (0.3%). Amphipods found in the 

 stomachs consist primarily of the families Ampe- 

 liscidae (<0.1% each of Ampelisca agaxxizi, A. 

 spinipes, A uadorum, and Byblis serrata), 

 Oedicerotidae (<0.1% of Monoculodes edwardsi and 

 M. intermedius), and Hyperiidae (exclusively the 

 genus Parathemisto, 0.1%). The remaining crusta- 

 cean groups are the Mysidacea (comprised of 

 Neomysis americana, 0.7%, and Erythrops, <0.1%), 

 Cumacea (mostly Leptocuma, <0.1%, and some un- 

 identified diastylids, <0.1%), Copepoda (almost all 

 identified as calanoids, <0.1%), and "Other Crus- 

 tacea" (all of which was well-digested crustacean 

 remains, 0.3%). 



The only other stomach contents identified were 

 the cephalopods (Loligo pealei, 4.17c, and Rossia, 



Table 2.— Dietary composition of 2,622 silver hake 

 caught in the Northwest Atlantic during the years 

 1973-76. (+ indicates <0.1%.) 



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