661 



Abstract.— A population model incor- 

 porating temporal and spatial detail re- 

 vealed that the majority of eastern 

 Georges Bank haddock, Melanogram- 

 mus aeglefinus, were found on the Ca- 

 nadian side of the Canada-U.S. bound- 

 ary-. During spring they were more wide- 

 spread across the top of the bank and 

 subsequently migrated eastward so 

 that by fall almost all haddock were 

 found in the deeper waters on the Ca- 

 nadian side. There is a return mi- 

 gration to the top of the bank during 

 the winter The seasonal distribution 

 and migration of haddock has remained 

 stable since 1985 and migration rates 

 do not appear to be related to the ob- 

 served range of abundance. The distri- 

 bution pattern since 1985 appears simi- 

 lar to that observed between 1972 and 

 1984. In contrast, during 1963-71 had- 

 dock were more widespread throughout 

 the area in both spring and fall. Abun- 

 dance of haddock in the Georges Bank 

 and Gulf of Maine area was exception- 

 ally high in the earlier period, and had- 

 dock from the spawning component in 

 the Great South Channel area may 

 have accounted for a greater augmen- 

 tation to the eastern Georges Bank 

 population. In implementing strategies 

 for managing this transboundary re- 

 source, scientists will need to evaluate 

 the nature of haddock distributions in 

 order, in turn, to evaluate the implica- 

 tions of their strategies. 



Movements of haddock, 

 Melanogrammus aeglefinus, 

 on eastern Georges Bank determined 

 from a population model incorporating 

 temporal and spatial detail 



Lutgarde A.M. Van Eeckhaute 

 Stratis Gavaris 



Edward A. Trippel 



Biological Station 



Department of Fisheries and Oceans 



St Andrews, New Brunswick EOG 2X0, Canada 



E-mail address (for L A M Van Eeckhaute) Van EeckhauleLcfmardto-mpogcca 



Manuscript accepted 25 June 1998. 

 Fish. Bull. 97:661-679 ( 1999). 



The haddock, Melanogrammus 

 aeglefinus. on Georges Bank have 

 supported a commercial fishery 

 since the early 1900s. Since 1977, 

 with the extension of jurisdiction by 

 coastal states, only Canada and the 

 United States have conducted had- 

 dock fisheries on Georges Bank. In 

 October 1984 the International 

 Court of Justice (ICJ) established a 

 maritime boundary between Canada 

 and the United States in the Gulf of 

 Maine area. Subsequently, fishing 

 by Canada and the United States 

 on Georges Bank has been re- 

 stricted to these respective jurisdic- 

 tions (Fig. 1). The new boundary 

 line, referred to as the ICJ line in 

 our study, lies over an established 

 grid of statistical unit areas that 

 has been used to summarize land- 

 ings data since the 1930s. These 

 areas have been based on, among 

 other factors, considerations of bio- 

 logical stock structure (principally 

 cod, Gadus morhua, and haddock), 

 political boundaries, and practi- 

 calities of data collection (Halliday 

 and Pinhorn, 1990). Aggregates of 

 unit areas are used to determine the 

 boundaries of fisheries "manage- 

 ment units" — geogi'aphic areas de- 

 fined for regulatory purposes. 



Prior to establishment of the 

 maritime boundary, regulation of 



the haddock fishery was based on a 

 management unit encompassing all 

 of subarea 5, although it was recog- 

 nized that this unit included at least 

 two major spawning concentrations 

 ( Walford, 1938; Bigelow and Schroe- 

 der, 1953). Historical evidence in- 

 dicates that the most important 

 spawning concentration was on the 

 eastern part of Georges Bank 

 whereas the spawning was variable 

 among years over the Great South 

 Channel and the southern part of 

 the bank (Walford, 1938), Tagging 

 studies and other biological data 

 have shown that little mixing occurs 

 between haddock on Georges Bank 

 and those in surrounding areas, e.g. 

 4X (Fig. 1), which is situated north 

 and east of Georges Bank (Schuck 

 and Arnold, 1951; Grosslein, 1962; 

 Clark et al., 1982). Tagging studies 

 have also indicated limited east- 

 west movement within subdivision 

 5Ze. which is the eastern portion of 

 division 5Z and includes unit areas 

 g, h, j, m, n, and o (Fig. 1), as only 

 about 57c of returns from haddock 

 tagged off Cape Cod were reported 

 from areas east of 68°W and 95*^ of 

 returns from haddock tagged on 

 eastern Georges Bank were re- 

 ported from areas east of 69°W 

 (Grosslein, 1962). In 1990, Canada 

 adopted unit areas 5Zj and 5Zm, 



