Stoner and Ray: Strombus gigas in a marine fishery reserve 



561 



Distribution processes in the Exuma Cays 



In terms of both density and extrapolated total num- 

 bers there were more adult conch in the MFR near 

 WW than in the fished area near LSI. The two sites 

 were similar in terms of habitat, and they lie rela- 

 tively close together in the same oceanographic ba- 

 sin, yet there were density differences, most notably 

 in the shallow bank waters. We recognize that no 

 unreplicated comparison of two field sites can pro- 

 vide indisputable proof that an MFR is advantageous 

 to a stock unless the analysis includes long time se- 

 ries or data before and after closure of a fishing area, 

 or both (Stewart-Oaten et al., 1986; Osenberg et al., 

 1994; Underwood, 1994). Unfortunately we know of 

 no biological data for the Exuma Cays Land and Sea 

 Park collected before the fishing closure. This is a 

 common problem associated with studies of MFR's 

 (see Roberts and Polunin, 1991), and future studies 

 should use control sites and replication in both time 

 and space for definitive answers regarding the im- 

 pact of closing fisheries in reserve areas. On the other 

 hand, it is not surprising when stocks of exploited 

 species increase in closed areas. A more important 



Table 6 



Adult queen conch densities reported for two locations in 

 the Caribbean by depth interval. Data for Puerto Rico were 

 collected in 1985-86 (Torres Rosado, 1987) and data for 

 the LInited States Virgin Islands were collected in 1990 

 (Friedlander et al., 1994). See Table 1 for comparison with 

 the Exuma Cays sites. 



Puerto Rico 



Virgin Islands 



Depth 



(m) 



Density 



(no/ha) 



Depth 



(ml 



Density 

 (no/ha) 



0-5 

 5-10 

 10-15 

 15-20 

 20-25 

 25-30 







0.04 



0.035 



0.035 



0.05 



0.023 



0-6 



6-12 



12-18 



18-24 



24-30 



5.2 



4.2 



17.1 



10.9 



11.0 



issue may be whether or not the reserves contribute 

 to long-term conservation of species or whether or 

 not they preserve or enhance stocks in the surround- 

 ing waters. Answers to such questions require data 



