Delgado et al.: Translocation of Strombus gigas as a strategy to rehabilitate the Florida Keys conch population 



287 



rare alleles (Allendorf and Ryman, 1987). However, the 

 use of wild conch to enhance the spawning aggregations 

 eliminates this problem. 



Queen conch appear to be a prime candidate for reha- 

 bilitation by translocation because they meet the criteria 

 associated with successful translocations reported by 

 Griffith et al. (1989). These factors include release within 

 the historical range of the species or into areas of in- 

 creased habitat quality (or both). Additionally, herbivorous 

 animals stand a greater chance of translocation success 

 than do carnivores or omnivores. Lastly, wild animals 

 translocate more successfully than captive-bred animals. 

 According to these parameters, queen conch are ideally 

 suited for translocations. 



However, before a full-scale translocation program can 

 be implemented, there are some theoretical considerations 

 that must be addressed. For example, Stoner and Ray- 

 Culp (2000) reported that conch reproductive behavior 

 reached an asymptotic level near 200 conch/ha.; therefore, 

 it would seem advantageous to enhance reproductive ag- 

 gregations to that density. However, without high habitat 

 quality, translocations have low success rates regardless 

 of how many animals are released (Griffith et al., 1989). 

 First, we must ascertain if offshore habitats can support 

 the added number of conch or if the translocated or na- 

 tive animals (or both) will simply disperse after release 

 because of density-dependent factors (e.g., intraspecific 

 competition for limited resources). Conch grazing has been 

 shown to significantly reduce the biomass of seagrass mac- 

 rodetritus and epiphytes (Stoner, 1989). In addition, the 

 effects of removing nearshore conch from the nearshore 

 environment need to be investigated. 



Additionally, if increased recruitment is the ultimate 

 goal of the translocation program, larvae must survive 

 and be retained within the Florida Keys. At this point, it 

 is unknown whether larvae produced from translocated 

 nearshore conch are viable or as viable as the larvae pro- 

 duced by native offshore conch. Furthermore, the relative 

 contribution of local and upstream sources to recruitment 

 is unknown. Stoner et al. (1996, 1997) suggested that most 

 of the queen conch larvae entering the Florida Keys come 

 from upstream sources. If this is indeed the case, then local 

 translocations will not be as effective as an international or 

 regional management strategy. However, mechanisms for 

 larval retention in the Florida Keys have been described 

 by Lee and Williams (1999), who suggested that the pe- 

 riodic formation of gyres in the lower Keys may facilitate 

 the retention and recruitment of locally produced larvae. 

 If larvae are retained within the Florida Keys system, any 

 increase in local larval production will increase larval sup- 

 ply and may increase recruitment. Therefore, translocation 

 sites should be located in the lower Keys in order to ensure 

 maximum larval retention and recruitment. 



The present study has shown that translocation may be 

 a viable method for rehabilitating queen conch populations 

 in the Florida Keys. We have demonstrated that nearshore 

 conch that were translocated offshore regained some of 

 their reproductive capacity and abilities. Therefore, mov- 

 ing conch from nearshore larval sinks to offshore larval 

 sources may be the key to expediting the recovery of queen 



conch stocks. Further research (e.g., larval retention 

 studies, studies on the effect of water quality on larval 

 survival, carrying capacity studies) and monitoring will 

 determine the efficacy of this restoration strategy. 



Acknowledgments 



John Hunt, William Sharp, James Colvocoresses, Allan 

 Stoner, and one anonymous reviewer provided insightful 

 comments on the manuscript. Judy Leiby and Jim Quinn 

 provided editorial comments. We thank Mary Enstrom 

 and Sherry Dawson of The Nature Conservancy (TNC) as 

 well as the numerous TNC volunteers who participated in 

 the field surveys. Meaghan Darcy and other staff members 

 at the Florida Marine Research Institute assisted in the 

 field and in sample processing. This project was funded by 

 Partnerships for Wildlife Grant no. P-3 from the U.S. Fish 

 and Wildlife Service and by the Florida Fish and Wildlife 

 Conservation Commission. 



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