Abstract

Traditional techniques for recapturing hatchery-reared juvenile queen conch used in stocking programs have typically relied on researchers visually locating the outplants. This made recovering juvenile queen conch after release difficult and labor intensive because of their cryptic behavior. We present a low-cost method of recapture in which underwater metal detectors are used to locate. tagged individuals. We compared recapture efficiencies of this method with those of the traditional, visual location method. Hatchery-reared juvenile conch (7.4 cm siphonal length) were tagged by securing a numbered aluminum tag around the spire and were distributed haphazardly within a 10 m x 10 m grid in an established conch nursery. The outplants were allowed 24 hours to disperse. Subsequently, the plot was surveyed simultaneously by a pair of divers. One diver searched visually; the other used a metal detector. Significantly more conch were located with the metal detector than were found visually (n = 2, X 2 = 28.5629, d.f. = 1, p < 0.0001). Overall, 93.9% of the outplants were located with the metal detector, whereas 28% were located visually. Based on these results, we conclude that metal detectors provide a significant improvement over the traditional method of locating small queen conch used in recapture studies.

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