FISHERY BULLETIN: VOL. 84, NO. 1 



Comparisons of each exposure period within a 

 treatment with every other exposure period within 

 that treatment are shown in Table 2. In the bay, mor- 

 tality rates experienced by controls were significant- 

 ly different than those of lobsters exposed 1, 2, or 

 4 h. Additionally, lobsters exposed V2 h suffered a 

 significantly lower mortality rate than did those ex- 

 posed 4 h. However, some of these differences were 

 not significant among lobsters exposed at the Atlan- 

 tic reef site Among dampened lobsters tested there, 

 only the mortality rate of those exposed 1 h differed 

 significantly from that of controls and from that of 

 lobsters exposed V2 h. Among undampened lobsters 

 tested at the ocean site, mean mortality rates of con- 

 trols differed significantly only from those exposed 

 1 or 2 h. Differences between controls and 1 h ex- 

 posures were significant in every treatment, but 

 mean mortality rates never differed significantly 

 among lobsters exposed 1, 2, or 4 h. 



The mean mortality rate of all tested lobsters dur- 

 ing the first week following exposure was 11.2%, 

 which represents about 42% of all mortality; 54% 

 of all mortality in Florida Bay and 38% of all which 

 took place near Atlantic reefs occurred during the 

 first week (Table 1, Fig. 1). High mean weekly mor- 

 tality rates which occurred during week 1 decreas- 

 ed to much lower levels during week 2 (4.7%) and 

 week 3 (3.9%) in both bay and ocean (Fig. 2). Com- 

 parisons of mean mortality rates incurred during 

 week 1 with those of weeks 2 and 3 revealed signifi- 

 cant differences in every instance (Table 3). During 

 week 4, the overall rate increased to 6.1% (Fig. 2), 

 but this combined value masked highly divergent 

 changes in rates of mortality at bay and ocean sites. 



Table 2.— Results of Wilcoxon Two Sample Tests (Z values) 

 from comparisons of mean weekly mortality rates from dif- 

 ferent exposure periods for various treatments at Florida 

 Bay (Bay) and Atlantic Reef (Ocean) locations. C = con- 

 trols; exposure = hours. 



Bayside mortality rates actually decreased slightly, 

 whereas oceanside rates increased dramatically. 

 Statistical comparisons between mean mortality 

 rates during weeks 1 and 4 demonstrate significant 

 differences in the bay but not in the ocean (Table 3). 

 Graphic depictions of cumulative weekly mortality 

 rates (Fig. 1) reveal a decrease in slope after week 

 1 at both bay and ocean sites. These decreases in- 

 dicate reduced rates of mortality which persist 

 through the end of the experiment in the bay and 

 through week 3 in the ocean. However, the slope in- 

 creases sharply during week 4 in most oceanside 

 tests, indicating an additional period of high mor- 

 tality there. 



DISCUSSION 



Exposure unquestionably causes mortality among 

 Panulirus argus used to bait traps. Increasing ex- 



• = P < 0.05; 



P*S 0.01; 



P< 0.001 



Figure 2— Average weekly mortality rates (%) per treatment type 

 during weeks 1-4, all exposures combined. A = oceanside (Atlan- 

 tic Ocean) wet; B = bay (Florida Bay) wet; D = oceanside dry; T 

 = all treatments combined. 



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