Abstract. — In the summers of 

 1982, 1983, and 1985, almost 5000 

 commercial lobsters were trans- 

 planted from an area on the north- 

 east coast of Newfoundland to St. 

 Michael's Bay in southern Labrador, 

 about 200 km beyond their reported 

 northern limit of distribution, in an 

 attempt to establish a self-sustaining 

 population. Biological sampling of 

 these lobsters was carried out each 

 summer from 1986 to 1991. A con- 

 tinuous shift to larger sizes and a 

 generally high incidence of new-shell 

 animals indicated molting was a com- 

 mon occurrence in these lobsters. All 

 nonovigerous females had ovaries 

 developing for extrusion that sum- 

 mer, and their seminal receptacles 

 were full. In contrast, percentages 

 of ovigerous females were low and 

 most of these had extruded recently. 

 Many ripe females apparently failed 

 to extrude, and many that did ex- 

 trude lost the entire clutch before the 

 following summer. Exposure to tem- 

 peratures near or below 0°C from 

 mid-November to mid-May, and to 

 near-continuous darkness below a 

 layer of ice during most of this 

 period, may cause a high incidence 

 of resorption of ripe ovaries. The 

 incidence of ovigerous females with 

 recently-extruded eggs increased 

 substantially in the later years of the 

 study, indicating a degree of physio- 

 logical adjustment to the adverse en- 

 vironmental conditions. However, 

 loss of the entire clutch of eggs con- 

 tinued to be prevalent. Prolonged 

 low temperature certainly retarded 

 embryonic development for the fe- 

 males that extruded and retained 

 their eggs. Six of 17 ovigerous 

 females with old, eyed eggs had less 

 than half the yolk remaining. Only 

 one brood would have hatched by 

 early August, long enough in ad- 

 vance of autumn cooling for develop- 

 ment to Stage IV and settlement in 

 the area to be possible. Lobsters 

 transplanted to St. Michael's Bay 

 will not likely become a self-sustain- 

 ing population. Any recruitment that 

 might occur would certainly be too 

 little and too irregular to support a 

 fishery. 



Reproduction in American 

 lobsters Homarus americanus 

 transplanted northward to 

 St. Michaers Bay, Labrador 



Frank A. Boothroyd 



Biology Department. Memorial University of Newfoundland 

 St John's, Newfoundland AIB 3X9, Canada 



Gerald P. Ennis* 



Department of Fisheries and Oceans, P O, Box 5667 

 St John's, Newfoundland AlC 5X1, Canada 



The American lobster Homarus ameri- 

 canus occurs in the western Atlantic 

 Ocean from the Strait of Belle Isle 

 area of southern Labrador and the 

 northern tip of the island of New- 

 foundland south to North Carolina 

 (Cooper and Uzmann 1980). The spe- 

 cies supports commercial fisheries of 

 considerable economic importance 

 throughout most of its range. Its high 

 commercial value led to repeated at- 

 tempts to establish lobster popula- 

 tions on the Pacific coast of North 

 America, but none of the transplants 

 was successful (Conan 1986). In re- 

 cent years, the Provincial Govern- 

 ment of Newfotmdland and Labrador 

 transplanted commercial (mostly 

 adult) lobsters from an area on the 

 northeast coast of the island of New- 

 foundland to a location ~ 200 km be- 

 yond the reported northern limit of 

 distribution in St. Michael's Bay, 

 Labrador (Fig. 1). The bay extends 

 inland ~28km from the open coast 

 and contains numerous small islands, 

 features promoting a circulation pat- 

 tern that would aid retention and 

 eventual settlement in the area of 

 any larvae produced by the trans- 

 planted lobsters. This was an impor- 

 tant consideration, since the aim of 

 the transplant was to establish a self- 

 sustaining population that would 

 eventually support a fishery. 



Manuscript accepted 15 July 1992. 

 Fishery Bulletin, U.S. 90:659-667 (1992). 



* Reprint requests should be addressed to this 

 author. 



Lobsters were transplanted to St. 

 Michael's Bay in the summers of 

 1982, 1983, and 1985. Biological sam- 

 pling was conducted each summer 

 from 1986 to 1991. Our purpose is 

 to present observations related to 

 various aspects of population biol- 

 ogy, in particular, molting, mating, 

 ovary development, spawning and 

 embryonic development, and con- 

 sider the possibility of this trans- 

 planted population being or becoming 

 self-sustaining. 



Methods and materials 



Lobsters transplanted to St. Michael's 

 Bay were caught during May-June 

 by commercial fishermen near Com- 

 fort Cove, Notre Dame Bay, on the 

 northeast coast of Newfoundland 

 (Fig. 1). They were purchased from 

 a local buyer by the Newfoundland 

 and Labrador Department of Fisher- 

 ies and transported directly to St. 

 Michael's Bay by float plane. Trans- 

 plants were made in 1982, 1983, and 

 1985 and totaled 2174 males, 81-114 

 mm carapace length (CL), and 2310 

 nonovigerous females, 81-112mm 

 CL. Lobsters were released once on- 

 ly at eight widely-separated sites 

 around the bay where the shallow- 

 water habitat appeared quite suitable 

 for lobsters. 



The authors conducted biological 

 sampling annually in the summer- 



659 



