The Catch Of The Day - Kampachi
Knute Hogan, The Culinarian, March 2007

Open Ocean aquaculture provides an opportunity for innovative eco-friendly fish farming. Kona Blue, a new fish ranch, located off the Big Island of Hawaii, is at the forefront of open ocean aquaculture and gaining a lot of attention by producing a premium quality amberjack.

The amberjack, also known as kahala in Hawaii and kampachi in Japan, has meat that is often compared to hamachi which is coveted in Japan for sushi and sashimi. Hamachi is often referred to as yellowtail, (not to be confused with yellowfin), and is part of the tuna family.

In the wild, amberjack is among tropical species often prone to the ciguatera toxin. Fishermen have considered them undesirable fish and toss them back into the water rather than risk food poisoning. The combination of nature and disease has made farming this fish a viable proposition.

At Kona Blue's open ocean fish ranch, the fish cages are in waters that reach more than 200 feet deep. Kona Blue leases 90 acres of open ocean from the State of Hawaii, but actively uses just nine acres. The fish are raised in submersible cages in deep water, where ocean currents disperse the wastes. The technique may prove to be a model for other species of fish.

The cages, called Sea Stations, are oddly shaped structures made of steel and nets that stretch 80 feet in diameter and consist of a 65-foot tall center pole called a spar and a Saturn ring made of 12 segments. The nets, woven with a fiber used in bulletproof vests called dyneema, are attached to the steel frame. When the cages are fully submerged, they and the fish are protected from storms that would cause significant damage on standard surface cages, thereby separating them from other farms which use surface cages that need to be located in protected bays.

When harvesting, the cages are attached with a hose to an air compressor on a boat, that is linked by a diver to the spar. Much like a submarine, ballast can be filled alternately with air or water to shift the cage above or below the surface. The process of raising and lowering the cage can take 10 to 40 minutes. The full harvest process takes one to two hours.

Kona Blue has been leasing space at the Natural Energy Laboratory of Hawaii Authority, an ocean science and technology park located at Keahole Point in Kona, which offers space for research and commercial endeavors.

Wild and cultivated brood stock is maintained in large inland tanks, where they are allowed to spawn. The eggs are collected and kept in larval rearing tanks. Once the eggs hatch, the newborn fish are fed a zooplankton that is cultivated on site. About four to six weeks later, the fish are moved into to nursery tanks. The fish are eight to 12 weeks old when they are moved to the Sea Stations, where they spend about ten months before they are harvested. When harvested, the fish weigh about 4 to 6 pounds. The total weekly harvest averages about 15,000 pounds.

While most people agree there is no such thing as food free of contaminants, the actual concern is at what point the contaminants become a health concern. Kona Blue employs a firm called Surefish for quality inspection. Surefish quality testing is sensitive enough to detect contaminants at levels many times less than the limits set by the Food and Drug Administration.

The State of Hawaii requires frequent third-party testing of the water. Kona Blue sends water samples from and down-current of the farm site to test for ammonia and turbidity. Once every three months, the fish are tested for contaminant levels. Eventually, it will be once every two months. There have been no detectable levels of mercury or PCBs.

As a carnivorous fish, the kampachi are given a high-fat pellet feed that is manufactured from sustainable resources, and to minimize the feed used, the fish are fed once a day thus keeping them hungry enough that the food released is eaten quickly which prevents the feed from moving into the ocean. This once-a-day feeding also creates an optimum food conversion ratio: 1 pound of dried feed to produce 1 pound of fish. Other attributes of the fish include high levels of Omega-3s, a lengthy shelf life of up to two weeks and a fat content in excess of 30 percent (wild kampachi contain about 3 percent fat) which equates to flavor and moisture.

When confronted with all these factors, (particularly emerging eco-friendly aquaculture practices supporting sustainable aquaculture and informing the public) it is a responsibility held in part by food service professionals. Looking to the future, kampachi will most likely be available to meet the growing need for seafood sources apart from wild stocks.