278 



Abstract— Queen conch (Strombus 

 gigas) stocks in the Florida Keys once 

 supported commercial and recreational 

 fisheries, but overharvesting has 

 decimated this once abundant snail. 

 Despite a ban on harvesting this spe- 

 cies since 1985, the local conch popu- 

 lation has not recovered. In addition, 

 previous work has reported that conch 

 located in nearshore Keys waters are 

 incapable of spawning because of poor 

 gonadal condition, although reproduc- 

 tion does occur offshore. Queen conch 

 in other areas undergo ontogenetic 

 migrations from shallow, nearshore 

 sites to offshore habitats, but conch in 

 the Florida Keys are prevented from 

 doing so by Hawk Channel. The pres- 

 ent study was initiated to determine 

 the potential of translocating non- 

 spawning nearshore conch to offshore 

 sites in order to augment the spawning 

 stock. We translocated adult conch 

 from two nearshore sites to two off- 

 shore sites. Histological examinations 

 at the initiation of this study confirmed 

 that nearshore conch were incapable of 

 reproduction, whereas offshore conch 

 had normal gonads and thus were able 

 to reproduce. The gonads of nearshore 

 females were in worse condition than 

 those of nearshore males. However, the 

 gonadal condition of the translocated 

 nearshore conch improved, and these 

 animals began spawning after three 

 months offshore. This finding suggests 

 that some component of the nearshore 

 environment (e.g.. pollutants, tem- 

 perature extremes, poor food or habitat 

 quality) disrupts reproduction in conch, 

 but that removal of nearshore ani- 

 mals to suitable offshore habitat can 

 restore reproductive viability. These 

 results indicate that translocations 

 are preferable to releasing hatchery- 

 reared juveniles because they are more 

 cost-effective, result in a more rapid 

 increase in reproductive output, and 

 maintain the genetic integrity of the 

 wild stock. Therefore, translocating 

 nearshore conch to offshore spawn- 

 ing aggregations may be the key to 

 expediting the recovery of queen conch 

 stocks in the Florida Keys. 



Translocation as a strategy to rehabilitate 

 the queen conch (Strombus gigas) population 

 in the Florida Keys 



Gabriel A. Delgado 



Claudine T. Bartels 



Robert A. Glazer 



Florida Fish and Wildlife Conservation Commission 



Florida Marine Research Institute 



2796 Overseas Highway, Suite 119 



Marathon, Florida 33050 



E-mail address (for G. A Delgado) gabneLdelgado;g>fwc. state fl us 



Nancy J. Brown-Peterson 



Department of Coastal Sciences 

 College of Science and Technology 

 The University of Southern Mississippi 

 P.O. Box 7000 

 Ocean Springs, Mississippi 39566 



Kevin J. McCarthy 



National Marine Fisheries Service, NOAA 

 75 Virginia Beach Drive 

 Miami, Florida 33149 



Manuscript approved for publication 

 24 November 2003 by Scientific Editor. 



Manuscript received 20 January 2004 

 at NMFS Scientific Publications Office. 



Fish. Bull. 102:278-288(20041. 



The queen conch (Strombus gigas) is 

 a large marine gastropod harvested 

 intensively throughout the Caribbean 

 for its meat and shell. In the Florida 

 Keys, conch once supported commercial 

 and recreational fisheries, but overhar- 

 vesting severely depleted the popula- 

 tion. The harvesting of conch has been 

 banned in Florida since 1985, but the 

 population has not recovered to levels 

 that can support exploitation (Glazer 

 and Berg. 1994; Berg and Glazer, 1995; 

 Glazer and Delgado, 2003). Intensive 

 fishing may invoke depensatory mecha- 

 nisms as densities are reduced, limit- 

 ing the ability of conch to locate mates 

 and increasing the chance of recruit- 

 ment failure (Appeldoorn, 1995). This 

 seems to be the case in Florida because 

 the lack of recovery has been attrib- 

 uted to diminished recruitment due in 

 part to small spawning aggregations 

 (Stoner et al., 1997; Stoner and Ray- 

 Culp, 2000). 



Queen conch occur in the various 

 oceanside habitats of the Florida Keys 

 archipelago with the exception of Hawk 



Channel (Glazer and Berg, 1994). This 

 naturally occurring deep-water channel 

 runs parallel to the Florida Keys, be- 

 tween the island chain and the offshore 

 reef tract. The substrate on the bottom 

 of Hawk Channel is predominantly soft 

 sediment, which is poor conch habitat; 

 consequently, Hawk Channel serves 

 as a barrier to migration and isolates 

 nearshore from offshore conch aggre- 

 gations (Glazer and Berg, 1994). We 

 have been monitoring queen conch 

 stocks throughout the Florida Keys 

 since 1987, and despite extensive sur- 

 veys, we have never observed reproduc- 

 tive activity among conch in nearshore 

 aggregations (Glazer and Berg, 1994). 

 Conversely, reproductive behavior has 

 been commonly observed among conch 

 in offshore aggregations (Glazer and 

 Berg, 1994). Moreover, a preliminary 

 histological examination of conch from 

 these two regions indicated that the 

 gonads of offshore conch were capable 

 of undergoing gametogenesis, whereas 

 the gonads of nearshore conch were 

 nonfunctional (Glazer and Quintero, 



