where, 



M = total number of lobsters tagged = 31 (April 23 

 to April 30) and 17 (August 31 to Sept. 7), for 

 the April and September estimates. 



C = total number of lobsters seen during census 



sampling = 47 (May 1 to May 4) and 26 (Sept. 8 



to Sept. 13) for the April and September estimates. 



R = total number of tagged lobsters in the sample C = 27 

 and 9 for the April and September estimates. 



RESULTS 



Population Estimation 



Modified Schnabel population estimates for successive days of census sampling 

 are presented in Tables 1, 2, 3, and 4 for the lobster populations of Areas 

 1 through 4, respectively. All estimates are based on a corrected M^, the 

 number of tagged lobsters at large prior to the t*-" day of sampling, discussed 

 above. Schnabel estimates of N were relatively constant over the duration of 

 the study, excluding the first few estimates for Areas 1 and 2 (Figure 3) . 

 This constancy in N suggests that these populations were relatively stabile 

 with minimal natural mortality, emigration or immigration. Fishing mortality 

 is theoretically zero since commercial or sport fishing for lobsters was not 

 permitted in Lameshur Bay. Lateral movements along the shore, between study 

 areas, were virtually non-existent as will be discussed below. 



Schnabel estimates for Areas 3 and 4 increased at a linear rate with signifi- 

 cant changes occurring in July and September in Area 3 and during late July and 

 early August in Area 4 (Figure 4) . These increases in N indicate that tagged 

 lobsters were emigrating from their respective areas at a given rate and/or 

 that significant natural mortality was occurring selectively on the tagged indi- 

 viduals. Total counts of lobsters seen by divers during these periods suggest 

 that the population sizes of Areas 3 and 4 were relatively constant or were 

 declining gradually; therefore, either tags were being lost at a rate signifi- 

 cantly greater than that estimated above or immigration of untagged lobsters 

 was balancing the loss of tagged lobsters from the population through natural 

 mortality and/or emigration. Emigration is considered the primary source of 

 loss of tagged individuals. Observations on the behavior of tagged and 

 "harassed" lobsters support this hypothesis (see section on Impact of Divers) . 

 The sudden increase in N in July for Area 3 and July-August for Area 4 probably 

 represents a period of relatively great immigration of untagged lobsters. 

 Actual counts by divers during these times support this contention. The rela- 

 tively high rate of increase in N during September in Area 3 probably reflects 

 an increased rate of emigration of tagged lobsters as a result of intensive 

 pressure (recapture and observation) by divers operating from the TEKTITE 

 habitat. 



VI-39 



