HUNT ET AL.: EXPOSURE AND CONFINEMENT ON SPINY LOBSTERS 



ficance at probability levels of 0.05, 0.01, and 0.001. 

 Weighted cumulative average mortality values 

 were obtained by multiplying the relative effort (%) 

 in each treatment (eg, site, exposure period >Vz h) 

 by the cumulative mortality for that treatment and 

 then summing those values. 



RESULTS 



The mortality experiment was conducted four 

 times between January and September 1980 in 

 Florida Bay and six times between May 1981 and 

 June 1982 near Atlantic reefs. Wet vs. dry tests were 

 conducted with each oceanside replicate The un- 

 weighted average cumulative mortality calculated 

 from Table 1 for all lobsters exposed l k, 1, 2, and 

 4 h, both sites combined, was 26.3% at the end of 

 4 wk. Average weighted cumulative mortality in 

 Florida Bay was 20.8%, and that near Atlantic reefs 

 was 31.9%. When weighted for relative effort at each 

 site, the overall mortality rate increased to 28.5%. 



No tests were established at oceanside stations 

 during December, January, or February, so effects 

 of air and water temperatures on mortality during 

 exposure were tested only in Florida Bay. Of four 

 tests conducted there, two were established during 

 cool months (January, February; air 15.2°-21.0°C, 

 water 17.0°-17.5°C during initiation), and two were 

 established during warm months (May September; 

 air 27.6°-33.5°C, water 29.3°-29.5°C). Mean week- 

 ly mortality rates of lobsters during these tests 

 (winter x = 4.4%; summer x = 4.6%) were not sig- 

 nificantly different. 



Average mortality rates obtained in wet vs. dry 

 treatments (Table 1, Fig. 1) were not significantly 

 different for any exposure or subsequent confine- 

 ment period. Furthermore, neither wet nor dry treat- 

 ments consistently caused greater mortality. 



Because all Florida Bay lobsters were dampened 

 when exposed >1 h, comparisons of bay vs. ocean 

 mortality rates were made using wet treatments 

 only. All five treatments (Control, V2, 1, 2, and 4 h) 

 were combined and overall mean weekly mortality 

 rates were compared. The average weekly mortality 

 rate of lobsters in bay tests (x = 4.5%) differed 

 significantly (Z = 2.51, P < 0.05) from that of lobsters 

 tested in the ocean (x = 7.6%). 



45 



« 35 

 o 



25 



J2 



E 



o 



15 - 



Figure 1.— Cumulative mortality rates (%) for exposure tests: A. 

 Florida Bay, wet only; B. Atlantic reefs, wet only; C. Wet (W) vs. 

 dry (D), Atlantic reefs only. C = controls; exposure periods = Vz, 

 1, 2, and 4 h. 



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