Credit for the video: Ahmed Shaheen (Egypt)
Review: Abdel Rahman El Gamal (Founder of the website and video channel)
Typically, the fattening of bluefin tuna (Thunnus thynnus) is done in sea cages. The tuna is caught by purse seiners in the Mediterranean and the ones that are targeted for fattening are taken to cages in which they are grown for a period that might range from 6 months to two years depending on the initial and target sizes. Japan in the principal market for fattened tuna.
As the video –filmed in Italy- shows, caged tunas are fed on small oily fish such as herring, sardines, anchovies, and squid; the greater the fat content of produced tuna, the greater the price on the Tokyo fish market. Often these small fish that are fed to tuna are kept frozen and are thawed before feeding. This is done either at ambient room temperature or by pumping seawater over the frozen fish blocks.
There is a considerable debate and opposition against the use of small fish in feeding tunas. The main reason is the poor efficiency of the practice; 10-20kg of feed fish is needed to produce one kg of tuna. The has led to increased pressure on some fish species that are used for human consumption which has been seen by some groups as unsustainable and unethical towards the world’s poor/hungry, Moreover, some opinions warns that the feeding of the pilchards to the tuna is associated with the spread of diseases.
Note: the water turbulence within the cage indicates the aggressive feeding of tuna as demonstrated throughout this video