100,000 tuna will mark in the Indian Ocean

2004/01/22 Agirre Ruiz de Arkaute, Aitziber - Elhuyar Zientzia

• Ekologia

This work involves researchers from the AZTI Foundation, along with researchers from other countries. They study the typical tropical species of Indian Ocean tuna: yellow fin, serrucho and nun. In short, tropical tuna are currently the most common canned tuna, more common than bonito. AZTI researchers and other Australian, French and Canarian researchers have spent a month at sea to make their first attempt.

Difficult work

Finding and marking tuna is no easy task. In some cases, scientists should perform a real surgical procedure to mark tuna, as the probe is not placed on the skin. It will be inserted into the abdominal cavity and for this purpose a deep incision of the fish is made, with special care to introduce it more than necessary and not damage any essential organ. Then sew the wound before leaving the tuna in the water. And all in just two minutes, since it is not convenient for the tuna to have more than two minutes out of the water.

But in order to mark the tuna it is essential to find fish first and almost as difficult as marking. However, scientists know that any floating object in the water accumulates tuna under it. Fishermen throw many of these objects into the water, of any kind, but always attached to a buoy. Thus, the buoy sends them an exact position via satellite. AZTI researchers have also used fisherman buoys to look for tuna.

This first campaign has lasted a month, but it will take two or three years to go out to the sea and marking tuna. Those who know the most about the sea still know nothing. Even less, how fish stocks are found. The knowledge of tuna populations is even more difficult, since being migratory fish, they perform thousands and thousands of kilometers each year. Researchers are convinced that they will receive relevant information about the brands that will apply to them in this campaign.