694 



Fishery Bulletin 89(4), 1991 



Site description 



Experiments with juvenile queen 

 conch were conducted during the 

 summer of 1988, at eight sites in the 

 southern Exuma Cays, Bahamas, 

 near Lee Stocking I. (Fig. 1). These 

 sites included two which have 

 natural populations of queen conch 

 juveniles, Children's Bay Cay site 1 

 (CI) and Neighbor Cay site 1 (Nl). 

 Site CI had moderate turtlegrass 

 Thalassia testudinum biomass, and 

 Nl had low biomass (Fig. 2). Site Nl 

 had lower seagrass biomass than 

 the optimal for juvenile conch 

 reported by Stoner and Waite (1990) 

 but has had a persistent population 

 of conch since at least 1986. Two 

 sites were chosen with macrophyte, 

 sediment, and depth characteristics 

 similar to Cl, but with no resident 

 conch populations. Children's Bay 

 Cay site 2 (C2) was in the same 

 seagrass bed as Cl but 0.5km to the 

 southeast; the other site was west 

 of Lee Stocking I. (LI). An addi- 

 tional two sites were chosen for similarity to Nl: one 

 site was north of Lee Stocking I. (L3) and the second 

 near Windsock Cay (Wl). 



To examine the effects of seagrass biomass in ex- 

 treme cases, two additional sites were chosen. A sand 

 bank site, Children's Bay Cay site 3 (C3), was selected 

 where there was no macrophyte cover but which has 

 a regular transience of juvenile conch. One additional 

 site, Lee Stocking I. site 2 (L2), was chosen for high 

 seagrass and detrital biomass, 300m northwest of LI. 



Methods and materials 



Two topless cages were constructed at the eight ex- 

 perimental sites with 2.0cm black plastic mesh wired 

 to reinforcement bar driven into the sediment. The 



Figure 2 



Standing crop of Thalassia testudinum and macrodetritus 

 at sites where juvenile queen conch were transplanted. 

 Histograms are mean values found in enclosures at the 

 beginning and end of the experiment. Error bars are ± 

 standard deviation. Note the change of scale for macro- 

 detritus at station L2. Asterisks indicate stations with resi- 

 dent conch. Station C3 (not shoxyn) had zero macrophyte 

 biomass. 



76°05' 



- 23°50' 



- 23°45' 



Figure 1 



Map showing locations of transplant sites in the southern Exuma Cays, Bahamas. 

 Zero, low, mod., and high refer to density of seagrass at each site. 



