Off-bottom oyster aquaculture is a labor-limited industry with slim profit margins. Production inefficiencies can amplify the economic strain on a company. Therefore, any technique that improves production and reduces operational costs has tremendous potential to increase the economic sustainability of shellfish aquaculture. While previous studies have highlighted the benefits of low stocking densities (which presumably increases water flow and food availability), less is known about the effects of densities that trigger the practice of splitting, or thinning into lower densities. This project addresses this gap by investigating the effects of splitting oysters at three different triggering densities (25%, 50%, and 75%) on growth metrics, yield, and time-to-market.
In April 2023, 27 FlipFarm baskets were stocked with ~25 mm oysters at 10% of total basket volume and deployed across three lines on the VIMS Research Farm in the York River, Chesapeake Bay (9 baskets per line). Baskets were haphazardly assigned one of three thinning densities, and regularly observed for growth, split once a treatment level reached the trigger volume, and restocked at 10% by size class (creating additional baskets). To date, the 25% treatment has been split three times, the 50% treatment split twice, and the 75% treatment split once. Preliminary data show oysters in the 50% treatment grew faster than the 25% treatment over the second half of the sampling period (Fig 1). The cumulative mortality of these treatments has not differed. Anticipated splits in the coming months will provide further insights into yield, time-to-market, and estimated labor-related cost-benefit scenarios.