181 



Abstract-A total of 42,445 American 

 lobsters iWomaru.s americanus) wore 

 tagged in thirty-one sites throughout 

 the southwestern Gulf of St. Lawrence 

 betw^een 1980 and 1997. Results from 

 the recapture of 8503 tagged lobsters 

 showed small distances traveled be- 

 tween the release and the recapture 

 position for animals ranging in size 

 from 51 to 152 mm carapace length. 

 The average distance traveled ranged 

 from 2 km in parts of Bale des Chal- 

 eurs and western Cape Breton to 19 km 

 in central Northumberland Strait. Lob- 

 sters moved generally along the shore 

 (939J of the dispersion was in areas 

 between the shore and the 20-m bathy- 

 metric contour). As a result, lobsters 

 traveled longer distances in sites char- 

 acterized by a gradually sloping bottom 

 where the distance between the shore 

 and the 20-m contour line was exten- 

 sive in contrast to areas characterized 

 by rapidly changing depths and by a 

 relatively small amount of habitat shal- 

 lower than 20 m. In the majority of 

 sites (14 of 19) there was no significant 

 difference between males and females 

 in the average distance they traveled. 

 In four of the five sites females moved 

 farther than males. In general, the 

 average distance traveled by berried 

 females was shorter than that traveled 

 by males or nonberried females. No 

 relationship was obsen.'ed between the 

 distance traveled and the size of the 

 animal. There was no strong evidence 

 of a relationship between the average 

 distance traveled and the number of 

 days at liberty. In general, lobsters in 

 the southwestern Gulf of St. Lawrence 

 traveled short distances and dispersion 

 was restricted to the nearshore habi- 

 tat. Further, the distance traveled was 

 not correlated to size, sex, or years at 

 large. These findings show that there 

 is little interaction between American 

 lobsters from different fishing areas at 

 the benthic level and that American 

 lobster movements should have mini- 

 mal consequences for management of 

 the species in the southwestern Gulf of 

 St. Lawrence. 



Movement of American lobster 

 (Homorus americanus) in the 

 southwestern Gulf of St. Lawrence 



Michel Comeau 



Fernand Savoie 



Department of Fisheries and Oceans 



343 University Ave. 



Moncton, New Brunswick, Canada EIC 9B6 



E-mail address (lor M Comeau) comeaumm'dfo mpo gcca 



Manuscript accepted 14 September 2001. 

 Fish. Bull. 100:181-192 (2002). 



The American lobster (Homarus ameri- 

 canus Milne-Edwards, 1837) fishery in 

 the southwestern Gulf of St. Lawrence 

 (GSL) and for the entire Canadian Mari- 

 time Provinces has become the most eco- 

 nomically important fishery of coastal 

 communities. Consequently, there is 

 increasing interest by fishermen and 

 the fishing industry to better under- 

 stand the biology of the species and 

 factors that may play a role in the 

 fluctuations of landings, including pos- 

 sible lobster movements between lob- 

 ster fishing areas (LFAs). Fishermen 

 are particularly concerned by lobster 

 movements because the minimal legal 

 size increased in different LFAs in 

 the southwestern GSL throughout the 

 1980s and 1990s, and they want to 

 know whether lobsters returned at sea 

 in a given area could be recaptured 

 elsewhere. 



Several tagging projects have been 

 conducted in the past to study lobster 

 movements in the GSL (Table 1). These 

 tagging projects, initiated in the 1930s 

 by Templeman ( 1935), showed that the 

 average distance traveled by lobsters in 

 the GSL was generally less than 15 km 

 and that very few animals traveled up 

 to 70 km (for review see Stasko, 1980; 

 Lawton and Lavalli, 1995). Other tag- 

 ging studies conducted in inshore wa- 

 ters outside the GSL in Nova Scotia 

 (Wilder, 1974; Campbell, 1982, 1989; 

 Campbell and Stasko, 1985; Miller et 

 al., 1989; Tremblay et al, 1998), Bay 

 of Fundy (Campbell, 1986; Campbell 

 andStasko, 1986), Maine (Cooper, 1970; 

 Cooper et al., 1975; Krouse, 1981), New 

 Hampshire (Watson et al, 19991. Mas- 



sachusetts (Karnofsky et al., 1989) and 

 Rhode Island (Fogarty et al., 1980) 

 have also shown that lobster move- 

 ments were generally similar (4 to 18 

 km) to those from the GSL. However, 

 long-distance movements of more than 

 90 km for up to 20% of the animals have 

 also been observed for lobsters tagged 

 inshore (Dow, 1974; Fogarty et al., 

 1980; Campbell and Stasko, 1985, 1986; 

 Campbell, 1989; Robichaud and Law- 

 ton, 1997); the farthest distance trav- 

 eled reported was 798 km (Campbell 

 and Stasko, 1986). These long distances 

 traveled are more similar to those re- 

 ported for offshore lobsters tagged on 

 the continental shelf and over the off- 

 shore deep canyons (Saila and Flowers, 

 1968; Cooper and Uzmann, 1971; Uz- 

 mann et al, 1977; Fogarty et al., 1980; 

 Campbell et al., 1984; Campbell and 

 Stasko, 1985). Movements of more than 

 70 km have itever been reported for lob- 

 sters tagged in the southwestern GSL. 

 Since 1980, forty-six tagging studies 

 have been conducted throughout the 

 southwestern GSL, mostly in areas 

 where information on lobster movements 

 has been unavailable. These tagging 

 studies have covered fishing grounds 

 characterized by a flat bottom and hav- 

 ing a relatively smooth transition from 

 shore to 30 m and a narrow habitat 

 close to shore where changes in depths 

 occur over a relatively short distance. 

 The purpose of our study was to in- 

 vestigate the benthic movement of lob- 

 sters tagged in different locations with- 

 in the southwestern GSL by comparing 

 the distance traveled, number of days at 

 liberty, and size and sex of lobsters. 



