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Fishery Bulletin 92(2), 1994 



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Figure 1 



Cumulative mortality curves for enclosure experi- 

 ment I. Hatchery-reared and wild queen conch, 

 Strombus gigas, were held at three different densi- 

 ties at sites CI and C2. Initial numbers of conch in 

 the enclosures were 10, 20 and 49, yielding densi- 

 ties of 0.5, 1.0, and 2.5 conchm' 2 , respectively. 



the same rate at both sites (F ; ^=0.105, P= 0.747). 

 Wild conch grew significantly faster than hatchery 

 conch at site CI (F J55 =14.54, P<0.001) and C2 

 CF ; 52 =69.06, P<0.001) (Fig. 15). In growth period II 

 (June and July 1990) wild conch grew faster than 

 hatchery conch at both sites (Table 10, Fig. 15). 



Experiment II A second tether experiment con- 

 ducted at site CI from 7 February to 3 May 1991, 

 using wild conch and the few remaining hatchery- 

 reared conch from the free-ranging experiment, re- 

 sulted in mortality curves (Fig. 16) different from 

 the first tether experiment (Fig. 14). Mortality rates 

 did not differ between stock types at either 42 

 (F ;6 =0.871, P=0.387) or 84 days (F, e <0.001, 

 P=1.000). Mortalities were identical (65%) at the 84- 

 day termination of the experiment (Fig. 16). 



Comparison of experiments 



Mortality rates in hatchery-reared conch were higher 



than or equal to those of wild conch in all experi- 

 ments and at both study sites (Table 11). Equivalent 

 mortality rates were found in enclosures and in tether 

 experiment II run at the end of the study period. 

 Growth rates were higher in wild conch than in 

 hatchery-reared conch except during the second 

 5-week period of enclosure experiment I at site C2 

 and in enclosure experiment II at site C2, when 

 growth rates were equivalent. 



Site differences in mortality rates were relatively 

 consistent across experiments and stock types (Table 

 11). Mortality was always lower for both wild and 

 hatchery-reared conch at site CI than at C2, except 



