Why do you flip oyster cages?

In June 2017, triploid oyster seed was produced at the Louisiana State University oyster hatchery in Grand Isle, LA and nursed for four months. Juvenile oysters were delivered to Florida in accordance with the Florida Department of Agriculture and Consumer Services’ rules pertaining to oyster seed importation; a diagnostic report and certificate of inspection by a licensed veterinarian was obtained. In late September (2017), triploid oysters were deployed at a commercial grower’s lease located in North Dog Island Aquaculture Use Area off Cedar Key. At that time, oysters measured 52 mm in shell height (SH), 39 mm in shell length (SL), and 16 mm in shell width (SW). Oysters were stocked into 14 mm Vexar bags at 150 per bag. Seventy-two bags were placed inside 12 six-slot floating cages (OysterGro®). Three aerial drying regimes, from now on referred to as “flipping” regimes, were followed allowing for evaluation of four cages each flipped weekly, biweekly, and triweekly (Table 1). Three bags with an antifouling coating and three uncoated bags were placed in each cage (Figure 1). Placement of bags in each cage (three on the top level and three on the bottom level) was also followed throughout the growout period (Table 1). The bag position was determined when the cage was in the drying position during aerial exposure (Figure 1).

Table 1. Summary of field trials evaluating biofouling management strategies for triploid oysters cultured in floating cages.