396 



Fishery Bulletin 92(2), 1994 



Table 2 

 Mortality of tagged and untagged queen conch 

 (Strombus gigas) on tethers at the two experimen- 

 tal sites. Ten tagged and ten untagged conch were 

 tethered in each of four replicate blocks at each site. 

 Values are mean percent mortality ± SD (number of 

 dead conch). 



Mortality 



Site 



Tagged 



Untagged 



CI 



("J 



52.5 ± 12.6(21) 

 40.0 ± 21.6(16) 



45.0+ 12.9(18) 

 52.5 ± 9.6(21) 



In the first tethering experiment percent mortalities 

 (arcsine-transformed) did not differ among any of the 

 tag and site treatments (Table 2) ( ANOVA, F 3 ;2 =0.722, 

 P =0.558 for CI; F 3 , 2 =0.679, P =0.581 for C2). 



Free-ranging experiment 



Tag recovery Tag recapture rates for free-ranging 

 juvenile conch were related to both stock type and 

 location (Table 3, Fig. 4). Exhaustive searches in and 

 beyond the study area recovered all visible live conch, 

 and there is no reason to believe that hatchery conch 

 were seen and collected by the 

 divers less often than wild conch. 

 In fact, wild conch had burial rates 

 higher than hatchery conch (see 

 Behavior); therefore, the reverse 

 bias is more likely. 



In November 1990, approxi- 

 mately 7.5 months after initial re- 

 lease, 206 of hatchery-reared 

 conch were recovered from site CI 

 and 248 from C2, an overall recap- 

 ture of 9% of the original release 

 (Fig. 4). Recoveries of wild conch 

 from sites CI and C2 numbered 

 542 and 820 conch, respectively, an 

 overall recapture rate of 28%. The 

 highest proportion of loss occurred 

 during the first two months (April 

 and May 1990). After May, recov- 

 ery curves for both hatchery and 

 wild conch leveled off at both sites. 

 Tag recapture was consistently 

 higher for wild conch released at 

 site C2 (34% at experiment end) 

 than for those released at C 1 ( 22% ), 

 despite the presence of large num- 



100 



• • Wild - C1 (2543) 



» — ' Wild - C2 (2490) 

 ■o Hotchery - C1 (2552) 

 a Hatchery - C2 (2540) 



C* 



cu 

 > 

 o 

 o 



CD 



Months 



Figure 4 



Recovery rates for free-ranging hatchery- 

 reared and wild queen conch, Strombus gigas, 

 transplanted to sites CI and C2 in April 1990. 

 Values are percentages of the original conch 

 (April releases) found in June, September, and 

 November surveys. In parentheses are the 

 original numbers of tagged conch. 



Table 3 



Tag recovery summaries for hatchery-reared and wild queen conch 

 (Strombus gigas) released in two study sites near Children's Bay Cay, Ba- 

 hamas, in 1990. Adjustments to the original numbers of conch released in April 

 account for tagged conch taken from the free-ranging study to be used in enclo- 

 sure and tether experiments; these were subtracted from the original number. 



Site 



CI 



C2 



Stock type 



Hatchery Wild 



Hatchery Wild 



April to June (64 days) 



Original Number Released in April 

 Recovered Live 

 % Recovered Live 



June to September ( 100 days) 

 Adjusted Number Released 

 Recovered Live 

 % Recovered Live 



September to November (66 days) 

 Adjusted Number Released 

 Recovered Live 

 r 7r Recovered Live 



