News // April 30, 2017

To quantify the effects of seasonal harvests on ploidy type, several spawns using tetraploid oysters held from the spring 2016 spawn were attempted in the fall at a participating commercial hatchery; however, viable gametes were not obtained. Since availability of triploid seed was limited, it was decided to purchase single-set seed with project funds from the Louisiana Sea Grant oyster hatchery and Auburn University shellfish hatchery. Disease certifications and ploidy verification required by the Department of Agriculture and Consumer Services for out-of-state oyster seed were obtained. These stocks were combined. A similar number of diploid seed was obtained from a

Six months after seed oysters (average 25 mm in shell height) were stocked into 14 mm mesh Vexar bags (October 2016), they were harvested in April 2017 (12 months from spawn). Replicated field trials were conducted at the UF experimental lease within the Dog Island Aquaculture Use Area off Cedar Key to document the effects of ploidy (diploid versus triploid), stocking density (125, 150, 175 oysters/bag), and float design (square versus bullet) on oyster production. To determine growth, a sample of 35 oysters from each of the 42 bags (six replicate bags per treatment) were measured for shell height, length,