Optimizing the tumble culture method to improve Pacific Oyster quality, and reduce labor for shellfish farms in Southeast Alaska

Optimizing aquatic farm gear to reduce labor and increase oyster growth and yield is a goal for many Alaskan oyster farms. Tumble cages have become a popular culture method in other oyster growing regions, as they improve oyster shape, size and yield while reducing labor for farmers.

The tumble cage method has numerous advantages including:

1. Harnessing tidal and wave movement to improve oyster shape
2. Mixing oysters within the cages to prevent uneven growth or crowding without the energy requirement of mechanized tumblers
3. Creating an unfriendly environment for sea stars which reduces predation
4. Reducing labor by lowering the frequency of removing oysters from the water.

Previous trials of tumble culture methods in Alaska have been unsuccessful however, due to the turbulent conditions found at many Alaskan oyster farms. These conditions create an “over tumbling” effect where oysters and gear can be damaged. With a collaborative team of engineers, oyster farmers, and a biologist we will design, fabricate, and test Alaska-specific and farm-specific tumble culture gear. We will utilize industry standard SEAPA cages installed in custom fabricated Alaska-capable support structures.

Typically cages are suspended in a structure using clips on a line, allowing for a large and uncontrolled range of motion. In order to account for rough conditions at SE Alaskan oyster farms, we have designed a novel method of mounting the cage to the frames that allows us to both dampen and finely tune the cage motion. Caging systems will be tested at three existing oyster farms spread-out throughout Southeast Alaska, each with a unique location (tidal and subtidal) and limitations for oyster production. Due to the risk, financial, and staffing burden of testing new gear at individual farms. This collaboration with AFDF funding support is crucial to determine the viability and Alaska-specific best practices for this potentially game-changing oyster growing method.

Learn more here.