COMPARISON OF HADDOCK FROM GEORGES AND BROWNS BANKS 



By HOWARD A. SCHUCK and EDGAR L, 



Two large areas in the Northwest Atlantic 

 Ocean are of utmost importance to the United 

 Slates haddock fishery. These are the Georges 

 Bank area and the chain of Nova Scotian banks. 

 From these two areas comes over 95 percent of the 

 llnited States production of haddock. In the 

 years 1931 to 1949, the Georges Bank area pro- 

 duced ahout 2,092,000,000 pounds (round weight) 

 of haddock and the Nova Scotian banks better 

 than 910,000,000 pounds. 



These two areas are close geographically but 

 are separated by the relatively deep Fundian 

 Channel. The question of the effectiveness of 

 this channel as a barrier to the passage of had- 

 dock (Melanogrammus aeglejinus) between the 

 Georges Bank area and the group of Nova Scotian 

 l)anks is economically and scientifically important. 

 Its answer, among other things, determines 

 whether the haddock stocks in the two areas can 

 be expected to fluctuate simultaneously or whether 

 they must be considered separately in interpreting 

 observed fluctuations in abundance. 



It is possible that some intermingling of the 

 egg or fry stages may occur between the two banks. 

 Walford (1938), however, concluded that during 

 1931 and 1932 (the only years in which the drift 

 of young has been studie-d) Georges Bank, at 

 least, had received no recruits from other areas. 



Regarding the bottom-dwelling stages of had- 

 dock, various investigators (Needier 1930, Her- 

 rington 1944) expressed the opinion that inter- 

 migrntion between the two areas is negligible, 

 and that the populations iiduibiting the two areas 

 are largely independent. At present, direct evi- 

 dence from the movement of marked fish is 

 limited. Returns from haddock tagged in shallow 

 inshore waters have been obtained (Needier 1930, 

 Sehrocder 1942, Rounsefdl 1942, United States 

 Fish and Wildlife Service unpublished records), but 

 early tagging of large groups of haddock located 

 off shore was \msuccessful. The extremely deli- 

 cate haddock require special methods of collecting 



954348 O - 51 



ARNOLD, JR., Fishery Research Biologists 



and handling, particularly in deep water, if 

 returns are to be obtained. Recent attempts at 

 off.shore tagging from the Albatross III are proving 

 successful, l)ut it will be some time before enough 

 returns are available to determine how much mi- 

 gration occurs across the Fundian Channel. 



As for indirect lines of evidence, Vladykov 

 (1935) has shown small differences in the average 

 numbers of vertebrae in haddock from Georges 

 Bank and the Nova Scotian banks. The sig- 

 nificance of the differences is not known, as no 

 measures of variation of these averages were given. 

 Other data by Needier (1930) indicate differences 

 in the size composition and the growth rate be- 

 tween Nova Scotian and Georges Bank haddock. 

 But again only averages were given and the sam- 

 ples were taken by commercial gear which ex- 

 cluded the younger ages and possibly exercised 

 selection for the larger sizes of certain ages. 



Recent data collected on a cruise of the Albatross 

 III, research vessel of the United States Fish 

 and Wildlife Service, make possible a critical 

 comparison between the haddock from Georges 

 Bank and those from Browns Bank, the Nova 

 Scotian bank lying closest to Georges. By such 

 a comparison, it is the purpose of this report to 

 consider further the effectiveness of the Fundian 

 Channel as a barrier to bottom-dwelling stages 

 of haddock. In effect, this study supplements 

 Needier (1930) by including younger fish and by 

 providing stringent statistical comparison of data 

 from the two l)anks. 



In collecting the original data for this study 

 John B. Colton, -Jr., Frank A. Dreyer, Freeman 

 A. Pluff, Louis D. Stringer, and Roland L. Wigley 

 assisted. Sterling L. Cogswell am! Richard E. 

 Sayles prepared the scal(>s for study, and Manuel 

 Vieira prepared the illustrations. Robcit Kirk- 

 I)atrick summarized the 1950 Browns Bank data, 

 and John C. Marr, Chief, South Pacific Fishery 

 Investigations, reviewed the manuscript. 



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