The Loss of Bluefin Tuna from the World’s Oceans

A Pacific bluefin tuna swims in a tank in the Tokyo Sea Life Park in Tokyo, April 2, 2015. All but one of the nearly 160 tuna and bonito fish have died for unknown reasons over recent months, leaving this one tuna the last remaining fish of the vast tank's original population, local media reported.  REUTERS/Thomas Peter - RTR4VTIV
A Pacific bluefin tuna swims in a tank in the Tokyo Sea Life Park in Tokyo, April 2, 2015. All but one of the nearly 160 tuna and bonito fish have died for unknown reasons over recent months, leaving this one tuna the last remaining fish of the vast tank's original population, local media reported. REUTERS/Thomas Peter - RTR4VTIV

The bluefin tuna are the largest tuna and can live up to 40 years old. They are able to travel across oceans and can dive to as low as 4000 feet. They grow to as long as 10 feet and weigh as heavy as 1500 pounds. They are incredible hunters seeking out shoals of mackerel and herring with their incredible vision. They are capable of swimming at speeds of about 40 miles per hour. The tuna has one of the highest blood hemoglobin concentrations among fish, and the resulting large percentage of oxygen being delivered to the muscles, give it its incredible speed and power in the water.

The Bluefin tuna

It has always been a popular catch for game fisherman rivalling merlin and swordfish as their favourite catch. One tuna that was caught off Liverpool, Nova Scotia in 1934 took 6 men 62 hours to eventually land. There are three types of Bluefin, the Atlantic, the Pacific and the Southern. They vary in size but what they all have in common is that they are popular food fish. This is particularly the case in Japan where the top restaurants crave large tuna so that they can produce their raw delicacies such as sushi and sashimi.

The cost of the price for the tuna is not cheap. In January 2017 at Tsukiji market in Tokyo a 212-kilogram Bluefin tuna was bought for 500,000 UK pounds. This price was highly inflated as the buyer Kiyoshi Kimura saw it as a great marketing opportunity for his Sushi Zanmai restaurant chain. The overfishing of Pacific Bluefin tuna for these highly demanding markets, has resulted in a reduction in the population of the fish by 97%. The most worrying aspect is that 70% of the fish that are caught are less than one year old. By the time the fish are three they have only a 5% chance of surviving, and this is hampering the fish’s chance of being able to reproduce.

The Tuna that cost 500,000 UK pounds

That Japanese catch 80% of all tuna that is landed. In 2015 Japan and other members of the Western and Central Pacific fisheries Commission agreed to halve the numbers of tuna weighing under 30kg from the average caught between 2012 and 2014. By April 2017 it was found that the Japanese were going to hit their quota two months early. Some fisheries in Japan are ignoring the quota as there are no financial penalties. Yet there are people in the country who are really worried about the stocks of the fish. Aiko Yamauchi, the leader of the oceans and seafood group for the world wildlife fund in Japan, feels that the quotas should be mandatory with failure to comply resulting in stiff financial penalties. The Atlantic Bluefin is also suffering from overfishing. There were large stocks of the fish in the Mediterranean but fishing from Italy Spain and North Africa has resulted in stocks being severely depleted.

The International Commission for the Conservation of Atlantic Tunas in 20017 set a quota of 22,500 tons of tuna per annum being allowed to be taken from the sea. In 2010 the quota was reduced to 13,500 tonnes when it was realized that in order to make the harvesting sustainable the limit should really be 7,500 tones. In reality with all of the figures available the international community are still happy to allow the amounts of tuna that are being fished from the oceans to outweigh the numbers that are being created by natural reproduction. This in future years could eventually lead to the extinction of the species.

Man has the power to control the numbers of this wonderful fish, but does it have the will power to implement the quotas which will allow it to survive.