FOOD HABITS OF GEORGES BANK HADDOCK 



The Georges Bank haddock ( Melanogrammus 

 aeglefinus Linnaeus) fishery yields approximate- 

 ly 94 million pounds o± fish annually. Production 

 of this weight of fish requires many more times 

 as much weight m food organisms . The fact 

 that the total production of haddock does not 

 vary widely from year to year indicates a 

 fairly reliable and constant supply of food. Is 

 this food supply reliable? Is it always com- 

 posed of the same species of organisms? Does 

 it vary from season to season? Does it differ 

 from one part of the bank to another? Is it 

 consistent from one year to another or are 

 there violent changes which affect the abundance 

 of new year classes as they begin their demer- 

 sal existence? Are the movements of the had- 

 dock over the bank influenced by variations in 

 the available food supply? Are the haddock 

 selective in their food habits or do they take 

 anytking they can catch? 



Georges Bank haddock are the fastest 

 growing m the world. Is this the result of 

 more abundant or more nutritious food? Some 

 year classes grow faster than others . Is this 

 related to variations in available food? What 

 species of fish compete with haddock for the 

 same foods and how detrimental is this com- 

 petition? 



These are some of the questions which 

 the food habits project of the North Atlantic 

 Fishery Investigations is attempting to answer . 

 The initial work m this study is the examina- 

 tion and analysis of stomach contents collected 

 primarily on commercial trawlers. No ex- 

 perimental design could be followed during 

 this stage of the study when observers were 

 collecting stomachs wherever the fishermen 

 happened to fish . 



The second stage of this study calls for 

 (1) sampling according to plan using the 

 Albatross in to fill in where samples from 

 -commercial trawlers are lacking; and (2) 



sampling the bottom invertebrate fauna in 

 the areas where stomach samples are 

 taken in order to relate the food captured 

 by haddock with the presence of food organ- 

 isms. 



This report presents the results of the 

 first year's study of haddock food habits. 



European biologists Jmve long been in- 

 terested in the food habits of haddock and 

 they have carried out many investigations 

 on this subject. Food studies of haddock 

 taken from waters surrounding the British 

 Isles have been particularly numerous. 

 Macintosh (1874), Trechman (1888), Smith 

 (1892), Scott, A. (1896), Scott, T. (1902), 

 Todd (1905, 1907), Carr (1907, 19D9), 

 Bowman (1923), Ritchie (1937), and Jones 

 (1954) are the most important contributors. 

 They found echinoderms, moUusks, 

 crustaceans, annelids, and fish to be the 

 common foods of haddock in that area . 

 Ritchie (loc. cit.) made quantitative analyses 

 of the stomach contents from thousands of 

 haddock . His work is the most thorough 

 study of haddock food habits that has been 

 made . Haddock from Scandinavian waters, 

 as xenorted by Idelson (1929), Blegvad 

 (1917), and Poulsen (1928), were found to 

 subsist largely upon mollusks, echinoderms, 

 annelids, and crustaceans . Food of haddock 

 from Icelandic waters has been reported by 

 Thompson (1929), Brown and Cheng (1946), 

 and Fridriksson and Timmermann (1950) . 

 Echinoderms and annelids were the pre- 

 dominant food Items; crustaceans, mollusks, 

 and fish occurred less frequently. 



North American biologists have carried 

 out comparatively few investigations per- 

 taining to haddock food habits , Haddock 

 from Nova Scotian waters have been exam- 

 ined by Willis (1890), Needier (1929), 

 Vladykov (1933), and Homans and Needier 



