According to the AZTI-Tecnalia researchers, the first estimations of the geographical location of the recovered tag revealed that this fish had undertaken migrations between the Azores and Portugal during the winter, later to return to the Gulf of Bizkaia in spring and also that it had dived, during the winter, to depths of more than 1000 metres.
The bluefin tuna was tagged 26 of August 2008 in the Gulf of Bizkaia at coordinates 4334'N and 200'W and that day it measured 89 cm. fork length and its weight was 13.5 kilograms. When caught, it was at 4444'N and 249'W, weighed 22.3 kilograms and its length was 104 centimeters. The electronic tag used in this case was provided for the project by the University of New Hampshire in the United States, within the remit of the cooperation agreement for the tagging of juvenile bluefin tuna in the North Atlantic. The fishing was undertaken with the collaboration of the San Sebastin and Hondarribia Sailing Clubs.
Conventional tagged fish are identifiable by a a visible tag on the second dorsal fin of the fish. During the release, once its biological data - species and size have been noted and the time, date and position of the catch, as well as the state of the sea, amongst other parameters, the animal is tagged and freed. When the fish is caught again the information is sent to AZTI-Tecnalia, where it is analyzed together with all other recapture details. In this way, comparing initial and final information helps to determine variables such as growth and migration rates, data that is of great interest to the scientific community, the fishing sector and can help the stock assessment.
However, in this case, the electronic tag used was surgically implanted in the peritoneal cavity of the fish and, besides the previously mentioned data, it also stored information about temperature, pressure and light intensity, which enables a detailed monitoring of the medium in which the fish is moving at any time
|Contact: Irati Kortabitarte|