404 



Fishery Bulletin 92 [2), 1994 



may be speculated: 1) hatchery and wild conch were 

 different in their metabolic functions, such as parti- 

 tioning of energy into somatic and shell growth, 2) 

 slow growth in hatchery-reared conch was a suble- 

 thal effect of transport, or 3) poor growth was re- 

 lated to behavioral characteristics of hatchery-reared 

 conch, such as a reduced ability to recognize foods in 

 the new habitat or unusually high motility. Labora- 

 tory experiments by Siddall (1984b) showed that 

 10-mm juvenile queen conch held at high density had 

 high locomotory activity and associated low growth 

 rates. Seemingly constant motion and lack of burial 

 in our hatchery-reared animals suggest that their 

 metabolic demands may have been high. However, 

 high growth rates in the hatchery conch later in our 



o 

 o 



o 



a? 



£ 

 o 



80 



60 



• — • Wild - Ct 



▲ — A Wild - C2 



O — O Hatchery - C1 



A — A Hatchery - C2 



^ 



Days 



Figure 1 2 



Cumulative mortality curves for enclosure experi- 

 ment II. Hatchery-reared and wild queen conch, 

 Strombus gigas, were compared at sites CI and C2. 

 Forty conch of each stock type were held at each site. 



investigation showed that the problem was not a per- 

 manent characteristic of the stock type, and others 

 have shown that hatchery-reared conch can have 

 normal growth rates in the field (Appeldoorn and 

 Ballantine, 1983; Davis et al., 1992). Nevertheless, 

 as suggested earlier (Stoner and Sandt, 1991, 1992), 

 growth appears to be a very sensitive indicator of a 

 seed animal's physiological performance in a new 

 habitat. 



A more serious difference occurred in mortality 

 rates. From the first field experiments with hatch- 

 ery-reared queen conch juveniles (Appeldoorn and 

 Ballantine, 1983) it has been clear that small conch 

 are highly susceptible to predation. Recommenda- 

 tions for release size range from 4 cm shell length 



