FOGARTY ET AL : MOVEMENT OF AMERICAN LOBSTER OFF RHODE ISLAND 



the outer continental shelf (Cooper and Uzmann 

 1971; Uzmann et al. 1977), these data indicate an 

 intermixing between offshore and inshore lobster 

 populations. Independent confirmation of seasonal 

 inshore-offshore movements has been obtained 

 using a stratified random trawl survey conducted 

 in spring and fall by the National Marine 

 Fisheries Service (Burns et al. ). 



Lobster stock identification studies based on 

 electrophoretic techniques (Tracey et al. 1975) and 

 linear discriminant analysis of morphometric 

 data (Saila and Flowers 1969) indicated that in- 

 shore and offshore groups are discrete. Tracey et 

 al. (1975) noted generally low levels of genetic 

 variability, but inshore and offshore lobsters were 

 differentiable at one locus of the 44 examined. 

 Saila and Flowers (1969) reported significant pro- 

 file differences between inshore and offshore 

 lobsters. These studies would indicate that in- 

 shore and offshore groups retain their genetic 

 identity despite seasonal intermixing. Migra- 

 tional studies do indicate the possibility of genetic 

 exchange between areas, perhaps explaining the 

 low levels of genetic variability (Tracey et al. 1975) 

 and some of the inconsistencies noted by Saila and 

 Flowers (1969). The period of intermixing does 

 correspond to periods of molting and mating activ- 

 ity. Further research on inshore-offshore stock in- 

 teractions is clearly needed to resolve these ques- 

 tions. This factor assumes particular importance 

 since it is possible that coastal sites are depen- 

 dent on recruitment from offshore areas to sustain 

 inshore populations that are subjected to ex- 

 tremely high levels of fishing mortality. 



ACKNOWLEDGMENTS 



We would like to express our appreciation to 

 Richard Sisson, Timothy Lynch, Arthur Ganz, and 

 James Herrmann for assistance in the field. James 

 Yoder kindly provided a computer program for 

 analysis of movements. We are grateful to Barbara 

 Simon and Ellen Yoder for programming and data 

 management and to Linda Gray for typing the 

 manuscript. Thomas D. Morrissey, Saul B. Saila, 

 and J. Stanley Cobb critically read the manuscript 

 and offered many helpful suggestions. 



/'Bums, T. S., S. H, Clark, V. C. Anthony, and R. J, Es- 

 sig. 1979. Review and assessment of the USA offshore lobster 

 fishery. Int. Cons. Explor Mer Shellfish Comm. CM. 1979/ 

 K:25,31p. 



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