Wild Tuna vs Farmed


  Wild tuna Farmed tuna
Volumes Globally 5.6 Million Ton (99,9%)

5.544 Ton (represents only 0.1% of the wild catches)

Available species Skipjack , Tongol, Albacore Yellowfin, Big-eye,and Bluefin 
(More info species guide)

Bluefin (Southern, Northern and Atlantic Bluefin tuna)
Yellowfin farming only experimental

Living environment Living in the high seas – swimming freely – their entire life span

Living in circular floating cages in coastal areas – usually for no more than one year

Feeding behavior Very variable, natural, depending on migration pattern, the prey available on the spot and the characteristics of the eco-system.

Based on wild fish sardine, squid and mackerels. This involves that these fleets go for fishing these wild species, and then transport them frozen to farms in order to provide feed  for fattening the bluefin.

Sizes Available in all sizes

Bluefin between 60 and 100 kgs

Weight conversion rate Fed naturally – irregular pattern

15.8 Kg of feed needed for the tuna to gain 1Kg of body weight

Fishing method Purse seiner on FADs,
Purse seiners on free schools (Unassociated),
Purse seiner associated,
Pole & line,
Hand line and
Long liners.

Catching by purse seiners – wild bluefin is kept alive within the net and then carefully transferred into cages  or pens for fatting in floating cages in the ocean. Recently there are 2 centers for breeding Bluefin tuna from fertilization to maturity in captivity (the closed cycle) for Bluefin in Japan and Spain. Experimental research in Yellowfin hatchery in Panama.

Status of the tuna stocks Only the big-eye tuna species in the Pacific approaches overfishing

Overfished globally

Sustainability claims Some fisheries for Albacore, Yellowfin and Skipjack have been MSC certified

Not yet possible

Pollution and contamination No negative impact; fully in balance with the ecosystem

* High pollution comes from solid waste (droppings and unconsumed feed) onto the sea bottom in coastal areas and dissolved nutrients into the water column.

* Use of chemicals that include antifoulants to keep cages free from colonial algae and animals; and therapeutants to deal with disease and parasitism.

Energy use (carbon footprint) (2009) *Purse seiner (Skipjack and Yellowfin)  368 liters of fuel per live weight ton of landing.

*Pole & line (Skipjack and Yellowfin) 1485 liters of fuel per live weight ton of landing

Average fuel consumption varies slightly by ocean.

*Purse seiner (Bluefin)  estd. 400 liters of fuel per live weight ton + fuel spent in catching bait (sardines, mackerel and squid)

*Catching baits
Mackerel 80 liters/ton (Atlantic)
Small pelagic 106 liters/ton (Atlantic)

Availability – Fishing areas All oceans worldwide Farming areas : Mediterranean sea especially in Spain, Malta and Croatia; South Western Pacific ocean in Japan and Australia
Central Eastern Pacific ocean in Mexico

Markets Fresh, frozen and processed (canned, pouches, glass jars)
Consumed globally

Fresh (sashimi and sushi) - 90% goes to Japan. Frozen (Ultra Low Temperature minus 60 Celsius) also mainly Japan.

Nutritional value Very similar content of: Protein, sodium, carbohydrate and total fat. Farmed Bluefin has an exceptional high fat content
species guide1