 Farm-raised tuna generally have a higher fat content than wild tuna.A one-metre tuna needs about of live fish to gain of fat, and about 1.5 to 2 tons of squid and mackerel are needed to produce a bluefin tuna.Research evaluating ingredients for use in southern bluefin tuna feed is ongoing, and gathering information on ingredient digestibility, palatability and nutrient utilisation and interference can improve lower costs for tuna ranchers.