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Fishery Bulletin 102(2) 



most resident nearshore females contained no germ cells. 

 The latter condition may have been due to the fact that 

 egg production is more costly bioenergetically than sperm 

 production (Ricklefs, 1990). 



Mating and spawning do not occur among resident near- 

 shore conch presumably because of their retarded gonadal 

 development; however, the translocation of nearshore 

 conch to the offshore region mitigated the deleterious ef- 

 fects that the nearshore environment had on their gonadal 

 development. The reproductive tissues of translocated 

 nearshore conch began to develop during the summer 

 after the conch had spent about three months offshore. 

 Most translocated female conch were in the early stages 

 of gonadal development, whereas most translocated male 

 conch were ripe. We believe this difference in gonadal de- 

 velopment is due to the fact that the starting gonadal con- 

 dition of nearshore females was worse than the starting 

 condition of male conch. By fall, after six months offshore, 

 most translocated females had become ripe. In addition, 

 the percentage of gametogenic tissue in the gonads of both 

 sexes increased through the summer and fall. 



In conjunction with the improvement in gonadal condi- 

 tion, nearshore females translocated to the offshore region 

 were observed spawning during the summer and fall; 

 however, no mating was observed among nearshore conch 

 translocated offshore. Resident offshore conch also had low 

 mating frequencies (<6"7r ). Similarly low mating frequen- 

 cies have been reported in the Virgin Islands (Randall, 

 1964) and the Bahamas (Stoner et al., 1992). We suspect 

 that the lack of observations of nearshore conch mating in 

 the offshore region may have been an artifact of the low 

 probability of encountering that activity due to the small 

 number of nearshore conch translocated offshore. Never- 

 theless, we believe mating must have occurred because 

 translocated nearshore conch were observed spawning. 

 However, it is unknown if queen conch are capable of lay- 

 ing unfertilized egg masses. 



The beginning of reproductive activity in queen conch 

 is linked to the start of spring, when water temperatures 

 begin rising (Randall, 1964; Stoner et al, 1992; Weil and 

 Laughlin, 1984). This same seasonal pattern was observed 

 in our study with resident offshore conch. They exhibited 

 the highest mating and spawning frequencies during the 

 spring and reproductive behavior decreased during the 

 ensuing seasons. However, compared with the spawn- 

 ing pattern of resident offshore conch, peak spawning in 

 translocated nearshore conch was delayed; peak spawning 

 occurred during the fall. Nevertheless, there was evidence 

 to suggest that the timing of reproductive behavior of 

 both resident offshore and translocated nearshore conch 

 might eventually become similar. Our results indicated 

 that it takes at least three months after translocation for 

 the negative effects of the nearshore environment to be 

 mitigated and for gonadal maturation to occur. The out- 

 of-phase spawning may have been prevented if the trans- 

 locations had occurred earlier in the year (e.g., January, 

 instead of March). 



Identifying the causative factor or factors that inhibit 

 the reproductive viability of nearshore queen conch re- 

 quires further study. However, the juxtaposition of the 



nearshore conch aggregations with human population cen- 

 ters suggests that anthropogenic changes to the nearshore 

 region may be partially responsible. Decreased reproduc- 

 tive output caused by anthropogenic contaminants has 

 been observed in several marine invertebrates, including 

 dogwinkles iNucella lapillus) (Bryan et al., 1987; Gibbs 

 and Bryan, 1986), scallops (Gould etal., 1988), sea urchins 

 (Krause, 1994; Thompson et al., 1989), and shrimps and 

 crabs (Wilson-Ormond et al., 1994). For example, chronic 

 exposure to tributyltin has been shown to sterilize females 

 of several species of mollusks (Matthiessen and Gibbs, 

 19981, and sublethal levels of copper greatly inhibited 

 gamete production and maturation in scallops (Gould et 

 al., 1988). There have also been numerous reports impli- 

 cating eutrophication in nearshore habitat degradation 

 in the Florida Keys (Lapointe et al., 1990; Lapointe and 

 Clark, 1992; Szmant and Forrester, 1996); however, very 

 little is known about the effects of increased nutrient levels 

 at the organismal level. 



The retarded gonadal condition in nearshore queen 

 conch may also be due to environmental factors such as 

 suboptimal habitat, poor food quality, or temperature 

 extremes associated with shallow water. Research on 

 bivalves has shown that habitat, diet, and food quality 

 directly affect gamete production (Le Pennec et al.. 1998: 

 Madrones-Ladja et al., 2002). As they increase in age and 

 size, queen conch undergo ontogenetic migrations from 

 shallow, nearshore sites to deeper-water habitats (Ran- 

 dall, 1964; Sandt and Stoner, 1993; Stoner, 1989; Weil and 

 Laughlin, 1984). It has been hypothesized that as conch 

 grow larger and require more food, they migrate to take 

 advantage of the augmented food supply in more produc- 

 tive offshore habitats (Sandt and Stoner. 1993; Stoner. 

 1989). However, nearshore queen conch in the Florida 

 Keys are prevented from migrating offshore by Hawk 

 Channel (Glazer and Berg, 1994). Therefore, translocat- 

 ing nearshore conch offshore would, in effect, link these 

 isolated environments. 



The implications of this study are of particular impor- 

 tance to the FWC-Florida Marine Research Institute's 

 ongoing queen conch stock restoration program. Trans- 

 locating naturally recruiting nearshore conch to offshore 

 areas would be more cost effective than hatchery produc- 

 tion of juvenile conch, especially because production costs 

 are eliminated and survival of translocated conch is likely 

 to be much greater than that of hatchery outplants (see 

 Stoner, 1997. for a review of juvenile mortality in stock 

 enhancement efforts). Translocations would also have a 

 more immediate effect on reproductive output than would 

 the release of hatchery-reared conch. A translocation pro- 

 gram would focus on moving large juveniles and adults 

 offshore, whereas a hatchery program must release small 

 juveniles (to minimize production costs) that would then 

 have to survive to maturity. Consequently, translocations 

 would quickly alleviate the depensatory mechanisms de- 

 scribed by Appeldoorn (1995) that can affect the recovery 

 of queen conch stocks. Finally, translocations provide the 

 added benefit of maintaining the genetic diversity of the 

 population. Hatchery-reared conch are typically derived 

 from a few egg masses and there is a concurrent loss in 



