There were no significant differences in shell height, total weight, meat weight, or survival of diploid oysters cultured at three stocking densities (125, 150, and 175/bag). White lines at the top of each bar represent the standard deviation, which is the variation among replicate bags. These data were averaged across stocking densities tested the number of replicate bags was 18 per ploidy type. The differences in growth and survival of diploid and triploid oysters cultured in 14 mm mesh bags supported by square floats are illustrated below. Nonetheless, results obtained for both ploidy types over a “winter” growing period (October through April) are considered commercially acceptable.įigure 2. In contrast, survival was higher in diploid oyster bags with an average survival of 97% triploid oyster bags had an average survival of 90%. Likewise, meat weights differed with triploid oysters averaging 13 grams and diploid oysters averaging 9 grams. Total weights were also significantly different with triploid oysters averaging 143 grams (3.2/lb) and diploid oysters averaging 109 grams (4.2/lb). The shell height of triploid oysters averaged 83 mm (3.3”), which was significantly higher than the average height of diploid oysters (76 mm, 3”). Measurements were averaged by ploidy type across all stocking densities tested. Results: Ploidy Comparison, Diploid (2N) versus Triploid (3N)Īfter six months in growout, differences in ploidy type were determined. From left to right, bottom: Measuring oysters for total weight (TW) and meat (wet) weight (MW) with an electronic scale. From left to right, top: Measuring shell height (SH), shell length (SL), and shell width (SW) with calipers. This information, which will be used to approximate labor costs, along with seed and gear costs will help to estimate profitability based on production data obtained in these trials.įigure 1. Throughout the six-month trials, the amount of time required to complete various tasks was recorded. These data were statistically analyzed to determine the significance of ploidy, stocking density, and float design on oyster growth and survival. Survival was determined by counting the number of live oysters per bag and dividing by the number of oysters originally stocked.
#Oyster spat student field worksheet verification
Another five oysters per bag were preserved for verification of ploidy, as well as 10 per bag were frozen to analyze later for dry meat weight, condition index, and biofouling. Susan Laramore for assessment of health (presence of parasites). In addition, a sample of five oysters per bag were shipped to Dr.
Pictures of meats and shells (external and internal) were taken to document appearance. Five oysters per bag were shucked and meats weighed. 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, and width and weighed (see Figure 1). 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. 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).
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