Abstract

The culture of larval and juvenile queen conch is a labor- and capital-intensive process that requires efficient systems, techniques, and protocols. We describe advances in water distribution, larval and nursery culture systems, and husbandry techniques devised to maximize efficiency in the queen conch culture program at the Florida Department of Environmental Protection. Advances in larviculture protocols include the design and implementation of software that calculates algal feed dilutions in static and flow-through systems for up to three algal species. Implementation of an ozone system to treat and condition incoming seawater resulted in larval production that approaches 20x the larval production in untreated water. Ozone injection is controlled by meters that electronically monitor the change in the oxidation-reduction potential of the seawater. A nursery system was developed and implemented for postlarval conch that includes downwelling feeding and upwelling cleaning phases. Algal culture tanks are integrated into the process in order to precondition the screens to be used as substrate for postlarval conch. A benthic diatom (Nitzchia sp.) isolated from local waters is used as the inoculum. After conch reach approximately 10 mm they are transferred to nursery system troughs and-are fed an artificial diet developed on-site that yields growth rates approximating those observed in the wild. The juvenile conch are cleaned and fed daily and culled by size at regular intervals. Feed rations are based upon conch wet-meat weight. All nursery troughs are covered and shaded 100% to reduce intraspecific interactions implicated in reduced growth rates. These advances have enabled the State of Florida’s queen conch hatchery to increase production to a maximum of 15,000 postlarval individuals per mouth while maintaining labor requirements at one culturist. Future research will focus on nursery system designs that will maximize production by increasing densities and, consequently, capacity without increasing labor requirements.

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