however, based on original release locations and dates. 

 Details concerning individual recaptures are referenced 

 to composite station number and listed in the appendix 

 tables of this report. 



Composite of Recoveries 



Figure 3 is a precision plot of the reported recovery 

 positions of all returns; in Figure 4 the same set of coor- 

 dinates are grouped by 6-minute squares to permit 

 readable numerical signature and to obviate overplotting 

 of identical recovery coordinates, some of which oc- 

 curred by chance, with others the result of multiple 

 recaptures by vessels fishing a given area for one or more 

 days. 



Comparison of Figure 3 with Figure 1 (original station 

 locations) shows overall dispersion from the original 

 release locations along the edge of the continental shelf. 

 Replotting of these data by release groups (Figs. 5-29) il- 

 lustrates the magnitude and direction of the individual 

 dispersions. 



Straight-line dispersion (point of release to point of 

 recovery) of individual lobsters is shown in Figures 5-29; 

 concentric circles having a radius of 10 and 50 nautical 

 miles (18.5 and 92.7 km) are drawn about each release 

 locality to indicate the magnitude and variability of 

 lobster movements from a given locality. Track lines of 

 50 miles (92.7 km) or greater are labeled with the return 

 number and sex (F or M). Where two or more recaptures 

 were made at the same reported locality, the solid circle 

 representing the recovery point is appropriately 

 numbered. In several instances (Figs. 20, 21, 24, 29) it 

 was necessary to group recovery data by 6-minute squares 

 for reasons described previously; in such cases, the nature 

 of the plotting is included in the figure title. 



Definition of Lobster Maturity 



Subsequent references to maturity stage of individual 

 lobsters assumes that the commonly prevailing 

 minimum legal size (81 mm carapace length) is an 

 acceptable beginning point at which both male and 

 female lobsters attain functional sexual maturity. Skud 

 and Perkins (1969) reported that demonstrable sexual 

 maturity, as evidenced by external embryonated eggs or 

 mature ovarian eggs, commenced at 80 mm carapace 

 length in large samples of female lobsters from the same 

 areas in which we conducted our tagging study. Stewart 

 (1972) examined 1,018 female lobsters from western Long 

 Island Sound and Block Island Sound for presence of 

 spermatophores in the seminal receptacle; the median 

 size of inseminated females in the sample (size range 53 

 to 106 mm carapace length) was 76 mm, and within the 

 size class 81-82 mm (53 specimens), 81% were in- 

 seminated. Krouse (1973) found that male lobsters from 

 the Boothbay region of Maine were virtually all sexually 

 mature well below the legal recruit size of 81 mm; these 

 findings were based on dissection of the genital tracts 

 and microscopic findings of mature sperm cells and sper- 

 matophores; Krouse (1973) reiterated the observations of 



Templeman (1934) that significant size disparity 

 between male and female lobsters precludes successful 

 mating and that prerecruit size males seem unlikely to 

 contribute materially to natural reproduction until they 

 attain a size equality with sexually mature females. 



MIGRATION VERSUS DISPERSION 



Cooper and Uzmann (1971) earlier hypothesized, on 

 the basis of a described time-temperature relationship, 

 that the nature of the migration phenomenon was a ver- 

 nal shoalward movement to warmer water with subse- 

 quent return to the edge and slope of the shelf with the 

 onset of fall and winter. In subsequent sections of this 

 report we will attempt to elicit qualitative and quan- 

 titative aspects of individual movements from groupings 

 of individuals referenced to release locality, point of 

 recapture, and time at large. 



Hypothetical track lines have been drawn in all cases 

 where dispersion or migration (definitions presented 

 below) from point of release to point of recapture exceed- 

 ed 10 nautical miles (18.5 km) (Figs. 5-29). We must con- 

 cede at the outset of this discussion that the magnitude, 

 direction, and time scale of a point-to-point track is 

 seldom an accurate portrayal of the exact movements of 

 any tagged animals; however, the assumption of a 

 straight-line track, however simplistic, is tenable for the 

 purposes of plotting, overview, analysis, and ultimately, 

 for distinction between the short-term probable migrants 

 and the longer-term dispersed individuals. The guiding 

 factors in this distinction of kinds, i.e., migrant or dis- 

 persed, are distance traversed and time at large, the 

 elements of the classical ground speed formula D/T. 



Ranking of the total array of recovery data by various 

 combinations shows that the maximum movement of 

 any recapture was 186 nautical miles (345 km) in 71 days 

 (2.6 miles/day). Other sesonable tracks in excess of 100 

 miles (185 km) were 125 (232 km)/86 days, 123 (228 km)/ 

 76 days, 118 (219 km)/107 days, 111 (206 km)/108 days, 

 and 102 (189 km)/29 days. Twelve other lobsters made 

 apparently directed tracks of 50-87 miles (93-161 km) 

 within 22-41 days. The calculated ground speeds of 

 these 31 examples range from 1 to 5.5 miles (1.8-10.2 km) 

 per day and indicate that directional movements in ex- 

 cess of 1 mile (1.8 km) per day are not uncommon if not, 

 in fact, quite normal. 



We have developed a classification scheme which 

 attempts to distinguish between directed migrants and 

 those whose net movements over time are inconsequen- 

 tial or not clearly directional; the 31 examples cited 

 above provide a logical basis for fixing constraints on the 

 numerical values of time and distance consistent with an 

 acceptable definition of the term "migrant." 



The frequency distribution of distance traveled shows 

 that 163 individuals were recovered within 0-9 miles (0- 

 16.8 km) of point of release over the time range 0-950 

 days. Clearly, there is no internal evidence that any of 

 these have dispersed significantly. In the time frequency 

 interval 0-9 days, 15 of 21 recoveries were common to the 



