Kona Blue Water Farms today released an analysis of its kampachi that demonstrates fish farmed in a sustainable manner have an ecological footprint 60 times less harmful on the ocean than wild-caught fish.
The Kailua-Kona, Hawaii, company's findings support Food and Agriculture Organization recommendations for an increase in aquaculture amid declining wild stocks and closures to key fisheries like West Coast rockfish, Gulf of Mexico grouper and East Coast red snapper.
"If we examine the true environmental cost of wild-caught predatory fish, such as swordfish or tuna, we find that sustainably maricultured fish have some 60 times less impact on fish stocks at the base of the food chain, such as sardines and anchovies," said Neil Anthony Sims, president of Kona Blue, which farms sashimi-grade Kona Kampachi®, a Hawaiian yellowtail.
"What would ocean-conscious consumers rather have on their plates - 1 pound of Kona Kampachi, or one sixtieth of a pound of tuna? The impact on the oceans is about the same," said Sims, basing his estimate on three primary considerations.
First, aquaculture is moving towards sustainable substitutes in fish feed to lessen reliance on fishmeal and fish oil. Kona Blue's current feed formulation includes only 35 percent fishmeal/fish oil from wild baitfish, of which approximately 3 percent is from capture fishery by-product. Contrary to outdated ratios of 5:1 or higher quoted by some environmental groups, the current ratio of "wild fish in to farmed fish out" has fallen to approximately 1.5:1 (0.5 pounds of anchovies producing 1 pound of sashimi-grade farmed fish).
By contrast, wild fish are subject to the laws of trophic transfer, where only 10 percent of their prey's food value is transferred up each step of the food chain.
"If a tuna eats a mackerel that earlier ate an anchovy, then there are two trophic steps, compounding the costs," said Sims. "A tuna may therefore need to eat the equivalent of 100 pounds of baitfish to increase its weight by 1 pound." As the fishmeal/fish oil for farmed fish feed involves only one efficient step, trophic transfer loss is minimized.
Secondly, Sims points out that farmed fish have a life cycle that is estimated to be three to 10 times more efficient than wild predatory fish, since they are harvested at a young age, after their most efficient growth, and do not expend energy reproducing or competing to survive in the wild.
The last consideration is bycatch. Some fisheries generate up to 11 pounds of bycatch for every pound that is retained, Sims said. Experts estimate that almost 30 percent of the global wild harvest is discarded. Farmed fish have no bycatch.
Sims said responsible open-ocean aquaculture is a key solution to the depletion of ocean resources, but cautioned, "We still need to ensure rational, effective management of baitfish resources, and take into account ecosystem impacts."
