188 



Fishery Bulletin 100(2) 



r 



65°20' 



65'10' 



r 



65°00' 



Bale des Chaleurs 



^^ * 



Ap Stonehaven 



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New Brunswick 



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_L 



Figure 4 



Locations (•• of tagged American lobsters recaptured in 1995 and 1996 (;i=296> from the 1994 tagging project 

 conducted in Stonehaven, New Brunswick. The release sites are indicated by a star symbol. 



Recently, a trawl survey conducted at a depth of 40 m in 

 the Caraquet area (Bale des Chaleurs) over a 7-month pe- 

 riod produced lobsters in mid-May, late-October, and No- 

 vember, but not between June and early-October ( Comeau, 

 personal obs.). Further, the recapture positions during the 

 fishing season showed that lobsters tagged during these 

 trawl surveys were recaptured along the coast at depths 

 less than 20 m from Stonehaven to Miscou (Comeau, per- 

 sonal obs.). This finding suggests that there is an inshore- 

 offshore movement on the south shore of Bale des Chal- 

 eurs similar to the one observed by Corrivault (1948) on 

 the north shore of that bay. Unfortunately, our tagging 

 projects were not designed to study this type of movement 

 and did not allow us to speculate more on inshore-offshore 

 movements. 



The lack of long-range movements across the south- 

 western GSL could be explained by the presence of an 

 extensive cold (<1.5°C) intermediate layer (CIL). In the 

 southwestern GSL, the CIL is a large volume of water 

 sandwiched between the coastal water and the deep wa- 

 ter located in the Laurentian channel. The top of the lay- 

 er ranges from 20 to 40 m depth from June to October 

 and rises to the surface from January to April (Gilbert 

 and Pettigrew, 1997). As it was hypothesized by Stasko 

 (1980), there seems to be no advantage in long-distance 

 movement to deeper water (>40 m) for lobsters in the GSL 

 because it is cold (<1.5°C) in both summer and winter 

 (CIL). Although lobsters can tolerate temperatures rang- 

 ing from -1.5° to 30°C, at temperatures below 0°C they 



are in a state of hibernation, and below 5°C molt induc- 

 tion is blocked (Waddy et al., 1995). It is clear that lob- 

 sters can "tolerate" cold temperature but to be active they 

 need warmer waters. Lobster movements of more than 

 40 km were rare in the southwestern GSL and movements 

 exceeding 70 km through deep, colder waters (>40 m) 

 were not observed. In contrast, lobsters from the Bay of 

 Fundy, from coastal waters of southwestern Nova Scotia, 

 and from coastal waters off New England can take advan- 

 tage of warmer temperatures in deep waters in the Gulf 

 of Maine and on the continental shelf during the winter 

 (Campbell and Stasko, 1986). Campbell and Stasko ( 1985) 

 and Campbell (1989) showed that lobsters tagged in the 

 inshore waters of southwestern Nova Scotia traveled up 

 to 240 km to the edge of the continental shelf off Georges 

 Bank to depths below 200 m, seemingly without crossing 

 a wide area of cold water. Similarly, lobsters tagged in the 

 Bay of Fundy were also recaptured in deep waters at the 

 edge of the continental shelf across the Gulf of Maine and 

 along the coastal waters of the United States (Campbell 

 and Stasko, 1986), at a distance of more than 780 km. 

 These types of movements were not observed in the south- 

 western GSL. Lobster movements between mainland New 

 Brunswick, Prince Edward Island, or Cape Breton, and 

 the Magdalen Islands, for example, have not been report- 

 ed. The Magdalen Islands are an archipelago with a sub- 

 stantial lobster fishery located in the middle of the south- 

 western GSL, surrounded by >60 m depths at about 80 to 

 90 km from Prince Edward Island, and Cape Breton. Lob- 



