662 



Fishery Bulletin 97(3), 1999 





4X ..-'•■ 



41 



Cape  5Zg 

 Cod 



^1 



NantucKeT 

 Shoals 



5Zo 



Great 

 South 

 Chanrjel 



5Zh 



\ 5Zj 



\ Q 



5'Zm ,•■■■' 



G ;orges Bank 



5Zn 



70 



69 



68 



67 



66 



65 



Figure 1 



Fisheries statistical unit areas in NAFO subdivision 5Ze (includes 5Zg,hj,m,n.o). The Ca- 

 nadian management unit for haddock comprises unit areas 5Zj and 5Zm (shaded!. 



eastern Georges Bank, as a management unit. 

 Gavaris and Van Eeckhaute ( 1990) summarized the 

 considerations on which the management unit bound- 

 aries are based. The ICJ line bisects this manage- 

 ment unit and imposes additional complexity for re- 

 source management considerations in the absence 

 of consistent practices by the two jurisdictions. A 

 prerequisite to investigation of harvest strategies for 

 the transboundary haddock resource is an under- 

 standing of haddock distribution and migration on 

 eastern Georges Bank in relation to the ICJ line. 



Earlier studies have described spatial distribution 

 of Georges Bank haddock and patterns in relation to 

 season, topography, time, and hydrographic condi- 

 tions (Colton, 1955; Grosslein, 1962; Overholtz, 1985, 

 1987). Our study focuses on the relative distribution 

 and net migration rates of haddock within the 5Zj,m 

 Canadian management unit in relation to the ICJ 

 line. Our objectives were to describe the relative 

 abundance of haddock on the Canadian and U.S. 

 sides of eastern Georges Bank since 1963 and to es- 

 timate rates of migration for haddock across the ICJ 

 line since 1985 when fishery statistics first became 

 available at a resolution sufficient to be summarized 

 with respect to the ICJ line. These results are neces- 

 sary for the evaluation of the effects of regulatory 

 measures, whether unilateral or bilateral. 



Methods 



Relative abundance 



Results from research vessel bottom trawl surveys 

 were used to estimate haddock abundance on the 

 Canadian and U.S. sides of the ICJ line on eastern 

 Georges Bank and to subsequently derive ratios of 

 abundance on the Canadian side to total 5Zj,m abun- 

 dance. Annual surveys have been conducted by the 

 U.S. National Marine Fisheries Service (NMFS) dur- 

 ing the fall since 1963 and during the spring since 

 1968 and by the Canadian Department of Fisheries 

 and Oceans (DFO) during the spring since 1986. 

 Ratios of relative abundance were calculated to 1993 

 for the NMFS surveys and to 1994 for the DFO sur- 

 veys, but survey data beyond those years were used 

 to illustrate haddock distribution patterns as the data 

 became available. All surveys used a stratified ran- 

 dom design but the strata boundaries differed (Fig. 

 2). The strata boundaries for the DFO survey were 

 modified to incorporate the ICJ line as a border in 

 1987. The results from the DFO survey in 1986, 

 which used a different strata design, were not con- 

 sidered in our study owing to the complication that 

 such a design would introduce and to the limited 

 additional information that would result. 



