MOVEMENTS OF TAGGED AMERICAN LOBSTER, HOMARUS AMERICANUS, 



OFF RHODE ISLAND^ 



Michael J. Fogarty,^ David V. D. Borden, ^ and Howard J. Russell" 



ABSTRACT 



In 1974 and 1975 a total of 3,063 American lobster, Homarus americanus. were tagged and released at 

 five sites along the Rhode Island coast and on the adjacent continental shelf. Analyses were based on 

 671 returns with sufficient information to assess movement patterns. Lobster movements at inshore 

 locations were generally localized; the mean distance between release and recovery sites ranged from 

 5.5 to 10.4 km. Intense fishing effort in inshore areas resulted in a disproportionate number of re- 

 turns within 30 days of release. Rayleigh tests demonstrated a nonuniform (P<0.01) distribution 

 of return directions at each site. Mean vector angles ranged from 164.5° to 193.7° from true north at 

 inshore locations. 



Lobsters tagged and released on Cox Ledge, 35 km southeast of Narragansett Bay, migrated to the 

 outer continental shelf in late fall and winter The mean distance travelled was 41.6 km and the average 

 time between release and recapture was 235.3 days. A Rayleigh test indicated that the distribution of 

 return directions was nonuniform iP<0.01) and the mean vector angle was 158.8° from true north. 



Analyses of the movement patterns of the Ameri- 

 can lobster, Homarus americanus, in coastal 

 waters have typically revealed little evidence of 

 extensive migrations. In a study designed to 

 examine seasonal movements, Wilder and Murray 

 (1958) noted a mean dispersion radius of <1.6 km 

 for tagged lobsters released off the coast of Nova 

 Scotia. Wilder (1963) reported movements averag- 

 ing 13.5 km for tagged lobsters at large 10-12 mo 

 off Price Edward Island. Bergeron (1967) con- 

 cluded that lobsters undertake a seasonal 

 onshore-offshore migration of about 10 km off the 

 Magdalen Islands of Quebec. In tagging experi- 

 ments conducted in the Gulf of Maine, Cooper 

 (1970) and Krouse^ noted generally localized 

 movements. Dow (1974) indicated, however, that 

 large lobsters ( >127 mm carapace length, CL) may 

 undertake migrations of over 140 km. Morrissey 



'This study was conducted in cooperation with the U.S. De- 

 partment of Commerce, National Marine Fisheries Service, 

 under grant 03-4-043-360. 



^Division of Fish and Wildlife, Rhode Island Department of 

 Environmental Management, Wickford, R.I.; present address: 

 Northeast Fisheries Center Woods Hole Laboratory, National 

 Marine Fisheries Service, NOAA, Woods Hole, MA 02543. 



^Division of Fish and Wildlife, Rhode Island Department of 

 Environmental Management, 150 Fowler St., Wickford, RI 

 02852. 



■•Division of Fish and Wildlife, Rhode Island Department of 

 Environmental Management, Wickford, R.I.; present address: 

 New England Regional Fisheries Management Council, Pea- 

 body MA 01960. 



^Krouse, J. S. 1977. Lobster tagging project No. 3-228-R. 

 Project completion report. Maine Department of Marine Re- 

 sources, West Boothbay Harbor, Maine, 29 p. 



(1971) presented evidence for directed movements 

 averaging 26.1 km for ovigerous and sublegal- 

 sized lobsters in the southern Gulf of Maine. Lund 

 et al.^ reported that lobsters tagged in western 

 Long Island Sound were nonmigratory while 

 others tagged in eastern Long Island Sound un- 

 dertook migrations to the edge of the continental 

 shelf. 



In contrast, Cooper and Uzmann (1971) and Uz- 

 mann et al. (1977) demonstrated an extensive in- 

 shore spring migration for lobsters tagged on the 

 outer continental shelf. Saila and Flowers (1968) 

 reported that ovigerous females displaced from 

 continental shelf waters to Narragansett Bay, R.I., 

 tended to return to the area of first capture. 



The present study was designed to examine var- 

 ious aspects of the population dynamics of lobster 

 off the coast of Rhode Island. In this paper we 

 describe the movement and migratory behavior of 

 lobster in local waters. The work was part of a 

 coast-wide research effort sponsored by the 

 State-Federal Lobster Management Program 

 under the auspices of the U.S. Department of 

 Commerce, National Marine Fisheries Service, 

 with the objective of developing a comprehensive 

 management strategy for lobster in the territorial 

 waters of the United States. >^ 



'^Lund.W A., L.L.Stewart, and C.J. Rathbun. 1973. Inves- 

 tigation on the lobster. Completion report. Commercial Fisheries 

 Research and Development Act. Project 3-130-R, 189 p. Univ. 

 Connecticut, Storrs, Conn. 



Manuscnpt accepted February 1980. 

 FISHERY BULLETIN: VOL. 78. NO. 3, 1980. 



771 -^7 



