Ear tag to help learn more about tuna

An ear tag for tunas - aimed at knowing more about the fish's aquatic life - is now ready.

The Hyderabad-based Indian National Centre for Ocean Information Services (INCOIS) seeks to use the tag - named PSAT (pop-up satellite archival tag) - to track the fish's movements with the help of GPS and satellite facilities in a bid to learn more about its habitat and create a database for fishermen communities.

The gadget is currently on display at the INCOIS stall at the World Oceanic Science Congress (WOSC) being held here.

The tag is attached to the gill of the fish after it is netted.

Weighing only 40 grams and measuring 12 inches that include the antenna, the instrument poses no difficulty for its wearer.

The PSAT will trace the path of the fish over a three-month period.

After 90 days, the tag will itself detach from the fish and float to the surface from where it would transmit information via satellite to the INCOIS monitoring system.

The PSAT-related research was in progress, said Rose P. Bright, an assistant with the pioneering project.

"As of now, the tool has been attached to 12 fish in the watery zones off Goa, Karnataka and Tamil Nadu. Four of them have delivered results," she said.

One tuna fish that was tagged with PSAT in Chennai is recorded to have swum around the entire island of Sri Lanka.

It is learned to have travelled in temperatures ranging between 20 and 27 degrees Celsius, seldom going deeper than a standard level.

Its travel path will also throws light on other varieties of fish and their habitat.

The study is important considering that data related to tuna in the Indian Ocean remains far less compared to that on their existence in the Atlantic and Pacific.