FISHERY BULLETIN: VOL. 82. NO. 1 



tion in the feeding intensity of silver hake on Georges 

 Bank in September 1978. They found that silver 

 hake feed more intensively at night than during 

 daylight. The findings of the present study are similar 

 to those reported earlier (for the same size fish col- 

 lected in autumn), but also indicate that an additional 

 feeding period may occur around noon during 

 springtime. No such pattern of feeding has been 

 noted for adult silver hake in the past. 



Differences in the composition and/or quantity of 

 food in the stomachs of silver hake collected within 

 various geographic areas have been observed pre- 

 viously by Schaefer (1960), Vinogradov (1972), and 

 Langton and Bowman (1980). Two items are par- 

 ticularly noteworthy concerning the diet of silver 

 hake in the different geographic areas studied here. 

 The first is the large quantity of food in the stomachs 

 of silver hake from the Middle Atlantic (on the 

 average two or three times more than the quantities 

 in the stomachs of Southern New England and 

 Georges Bank fish). The second is the high percent- 

 age weight (20.8%) of silver hake in the diet of silver 

 hake caught in the Middle Atlantic. Of interest is that 

 Langton and Bowman (1980) also found that silver 

 hake caught in the Middle Atlantic area (during the 

 period 1969-72) are more cannibalistic than silver 

 hake in other areas of the Northwest Atlantic. 



Vinogradov (1972) concluded that the differences 

 he observed in the feeding of silver hake in the 

 Northwest Atlantic during 1965-67 were "due to 

 variations from area to area in the species composi- 

 tion of the fish food and the rate of feeding." 

 Vinogradov's mention of "the rate of feeding" 

 referred to the variation in feeding intensity of silver 

 hake throughout the year. He found silver hake feed 

 most intensively in the spring-summer and autumn 

 periods. During the summer (when silver hake 

 spawn) and winter, he noted that the feeding rate 

 diminishes. The data presented here, in conjunction 

 with other published and unpublished data, tend to 

 corroborate Vinogradov's conclusions. Silver hake 

 caught in spring have twice as much food in their 

 stomachs as those caught in fall (data from present 

 study for 24-35 cm FL fish— 1.3 g, spring; 0.6 g, fall). 

 The stomachs of spawning silver hake contain small 

 quantities of food (0.1 g) compared with fish with 

 developing (1.0 g) or spent (1.3 g) gonads (data from 

 present study). Fish > 20 cm FL collected during late 

 summer-early autumn have small quantities of food 

 (mean stomach content weight of 0.2 g) in their 

 stomachs (Bowman and Bowman 1980). The 

 stomach contents of silver hake collected on Georges 

 Bank during the winter (December-January) of 

 1976-77 were analyzed by Bowman and Langton 



(1978). They found the mean stomach content weight 

 offish 20 cm FL and larger to be 0.4 g. The stomachs 

 of silver hake (all >29 cm FL) collected in February 

 (late winter) of 1977 on Georges Bank, by American 

 and Polish scientists aboard the Polish RV Wieczno 

 (conducting research in conjunction with the Woods 

 Hole Laboratory), contained an average of 0.1 g of 

 food (unpublished data available from the author). 

 The pattern of feeding intensity for silver hake 

 throughout the year, based on the above information, 

 is intensive feeding in the spring and early summer; 

 curtailment of feeding in summer and early autumn 

 (during spawning); resumption of feeding in the 

 autumn, but to a lesser degree than in the spring; and 

 finally a reduction in feeding throughout the winter. 

 Somewhat similar feeding patterns have been es- 

 tablished for other species of marine fish (Tyler 

 1971). 



Grosslein et al. (1980) reported an increase in bot- 

 tom trawl survey catches of American sand lance in 

 1976 in the Northwest Atlantic. The population up- 

 surge of American sand lance combined with the high 

 percentage weights of American sand lance found in 

 silver hake stomach contents during 1976 is an in- 

 dication of silver hake's opportunistic predatory 

 behavior. Availability of prey is probably one of the 

 most important factors in determining what types 

 and how much food silver hake eat. 



ACKNOWLEDGMENTS 



I thank M. Grosslein for his critical review of the 

 manuscript; J. Towns, J. Murray, and others for their 

 help in analyzing the fish stomach contents and in 

 tabulating the data; and especially G. Kelley, 

 laboratory typist, for her patience. 



LITERATURE CITED 



BlGELOW, H. B., AND W. C. SCHROEDER. 



1953. Fishes of the Gulf of Maine. U.S. Fish Wildl. Serv., 

 Fish. Bull. 53, 577 p. 

 Bowman, R. E. 



1975. Food habits of Atlantic cod, haddock, and silver hake in 

 the Northwest Atlantic, 1969-1972. U.S. Natl. Mar. Fish. 

 Serv., Northeast Fish. Cent., Woods Hole Lab. Ref. 75-01, 

 53 p. 

 Bowman, R. E., and E. W. Bowman. 



1980. Diurnal variation in the feeding intensity and catch- 

 ability of silver hake (Merluccius bilinearis). Can. J. Fish. 

 Aquat. Sci. 37:1565-1572. 

 Bowman, R. E., and R. W. Langton. 



1978. Fish predation on oil-contaminated prey from the re- 

 gion of the ARGO MERCHANT oil spill. In In the wake of 

 the ARGO MERCHANT, p. 137-141. Univ. R.I. Cent. 

 Ocean Manage. Stud. 



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