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Cultchless (Single-Seed) Oyster Crop Budgets for Virginia

Summary

There are two aquaculture production methods for oysters in Virginia: intensive culture (off-bottom, containerized) and extensive culture (loose on bottom). Intensive culture is also referred to as “cultchless” production because the oyster seed used is single-seed. Cultchless production is containerized for protection from predators and to improve growth rates and quality control. Containerization varies but most commonly consists of oysters deployed first in bags within cages that sit off the bottom. Then, when the oysters grow bigger, they are placed in cages without bags. Some producers grow their nursery oysters big enough so they can go directly into the cages without bags. Other methods include bags attached to rebar racks or bags within oyster floats. Intensive culture is more expensive because it requires more labor for gear and product maintenance. However, the end result is a single, more uniform product that sells at a higher price in the “boxed” or “half-shell” markets. The second aquaculture production method, extensive culture, is referred to as “spat-on-shell” or “cultched” production. This method is more traditional in that oyster larvae from a hatchery are set on clean oyster shells (cultch), planted directly on the bottom, and grown out in clusters. This production method is relatively less expensive because once the oysters are planted, there is little to no maintenance. However, mortality is higher overall for extensive culture, and the product is destined for the shucked market, which generally garners a lower price. Both production methods typically use sterile (triploid) oysters, which achieve fast growth, making the time to first harvest approximately 12 to 18 months. However, depending on where they are sited, oyster growth rate can be faster or slower than that timeframe. For the purposes of these crop budgets, only the intensive or cultchless method is considered.