When describing oyster aquaculture, it is tempting to think ‘there are a thousand ways to grow an oyster’. As the industry evolves, farmers are using their personal experiences to innovate on the go, and thus have come to a variety of gear types and husbandry tactics that best suit their needs and environments. Having spent time managing large-scale oyster farms on both the East and West coasts, my goal is to provide insights for farmers to help their operations succeed.
In the Northeast, annual farming patterns are heavily influenced by the weather. Particularly in the Damariscotta River, ME, the farming cycle consists of raising gear from the river bed in spring, thinning, planting seed, tumbling seed, then sinking gear; all while harvesting and maintaining the gear. Floating cages must be sunk in the fall to prevent winter ice and winds from destroying it. On the West coast, especially in California, ice is much less of an issue. The yearly husbandry involves planting seed from fall through spring; tipping racks, flipping bottom bags and harvesting occur year round. There is much less seasonality to oyster grow out on the West coast, and many farms plant seed at harvest density, typically in intertidal gear. Intertidal gear is growing in popularity on the East coast, due to the ability to ‘set it and forget it’. This gear type self-regulates biofouling, however on the West coast only for around 10 months; after that, barnacles and seaweed start to take over. On the East coast, intertidal gear is only used for about 4 months as a nursery in the summertime.
The differences between East and West Coast cultures that I see make the biggest impacts are the culture types of subtidal vs intertidal gear. While subtidal gear requires more year round effort to control biofouling, mortality can be as low as 4%. While intertidal gear requires less maintenance during grow out, proximity to the mud causes an average mortality of 50% in Tomales Bay, CA. Both coasts are adapting to the changing climate, where waters are warmer than ever before. The East coast is adopting more intertidal gear while the West coast is adopting more subtidal gear. Both gear types have their advantages, and will help growers succeed as this industry flourishes.