Farm Raised Bluefin Tuna

I recently came across a post on Ms. Glaze’s blog about a farm raised bluefin tuna called Kindai which caught my attention. My initial reaction was – how in the hell do you farm raise a fish that grows to around 1,000 pounds? As it turns out, they don’t grow this large in captivity. The Fisheries Laboratory at Kinki University in Western Japan are farm raising the over fished bluefin tuna in a healthy and ecologically sound manner that allows sushi aficionados to again taste the fat laden toro.

The name Kindai is an abbreviation of the Japanese translation of Kinki University. This farm raised tuna is the end result of lifelong research of Hidemi Kumai. Kumai spent 30 years devoted to establishing a way to raise this delicate species of tuna. Early attempts at capturing and transporting these fish proved a failure due to the easily bruised skin damaged by fishing nets as well as the fish’s necessity of constantly moving water to supply oxygen to the gills. In the nets, the fish would most often die. Once these problems were solved, Kumai quickly encountered other problems of captivity. The fish died quickly, but through trial and error he eventually kept a few alive and in 1979, the captured fish spawned for the first time. In these early spawning, the fry did not survive. This remained a constant until 3 years later when the fish stopped spawning altogether. However, Kumai got the fish to successfully spawn again in 1994 and managed to keep the fry alive through several more years of trial. By 2004, the first bluefish tuna raised from egg to adult in captivity was sold.

The tuna are held captive in 100 foot diameter pens in the open ocean and fed a diet of squid, blue mackerel, and sand eel. Once the fry are born, they must be removed to indoor tanks to avoid the cannibalistic nature of the adult fish. Once large enough, they are reintroduced to the open ocean pen where they grow until ready to sell. Once sold, each fish is accompanied with a certificate of authenticity as well as a life history of the particular fish.

Due to its high demand, and prices reaching a whopping $110 per pound, the bluefin tuna has been over fished. With this demand, it has been nearly impossible to force fishers to follow guidelines. In the Mediterranean, the fish is on the brink of extinction and the Atlantic population has been reduced by 90% since the 1970’s. Now, due to the work of the University, many chef’s are paying between $40 and $70 per pound for this fish being raised in a sustainable manner.


~ by Schwarvin on November 17, 2008.

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