October 16, 2014 — Predominantly west-to-east movements and geographical concentration – the Equatorial Pacific bigeye tuna’s behaviour is gradually revealing its secrets. This and other findings have been reported in a new scientific paper authored by scientists from SPC and the Inter-American Tropical Tuna Commission, published recently in the journal Fisheries Research.
Bigeye tuna: better management through better understanding
Bigeye tuna (Thunnus obesus) live in temperate-to-tropical waters of the Pacific Ocean. In the 1950s, this species began to be targeted by longline fleets; fishing then intensified in the 1990s as purse seine fishing developed, leading to overfishing in the 2010s.
Since 1977, Pacific Island countries and their development partners have realised that tagging is essential in order to gather information on the state of stocks, growth and tuna movements. Tagging with conventional tags has been providing these data for more than 60 years, while over the past 15 years or so, electronic tags have produced additional information, especially on fish behaviour.
Large-scale tagging campaigns
As the first glimmer of light appears on the horizon, bigeye tuna are being constantly reeled in by the trolling lines of the longliner ‘Pacific Sunrise’. One after the other, these tuna are placed on the tagging tables, where they are measured by the scientists, who insert a tag behind the second dorsal fin and return them to the water, all in under 10 seconds.
Read the full story from the Secretariat of the Pacific Community