The Center harvested the first crop of Atlantic cod ever to be farmed in the open ocean in 2006. The cod were the offspring of wild Gulf of Maine brood stock, collected by local fishermen and provided to Great Bay aquaculture in Portsmouth, N.H.
The cod first put their fins in the Atlantic in fall of 2003, when they were about six-months-old and the size of a penknife. After a four month stint in covered nursery pens, attached to the pier outside UNH’s Coastal Marine Lab, they were transported a 3,000 cubic meter Sea Station cage at the demonstration farm.
The cod were fed a formulated diet and periodically monitored by firsthand diver observations and video cameras. The fine scale movements of several fish were tracked using ultrasonic transmitters and underwater hydrophones. This evaluation revealed cod are most active in the day, and unlike many other species that school in circular patterns, they appear to move randomly and linger along the netting. They also practice moderation when feeding—not always partaking when food is delivered, or not feeding for the entire time it’s available.
In late spring 2005, researchers conducted a pilot live harvest. The fish were in excellent health and weighed about three pounds each. However, with available technology, the live harvest was labor intensive and challenging. Future success will require the appropriate infrastructure.
Harvest for the fresh filet market began in November and December of 2005. In this process, fish were pumped directly on to the boat through a harvesting tube inserted into the Sea Station cage. Researchers observed that while earlier harvests produced good quality flesh, as the fish approached spawning, the yield decreased and the flesh wasn’t as firm. They opted to wait until spawning had passed to complete the harvest in February 2006.
Research results indicate that while cod culture has promise, there are challenges to be overcome to insure that the process is profitable and sustainable. To address these questions, researchers stocked a new crop of cod was stocked at the demonstration farm in 2006.