The project will entail fisheries observers, in-port catch sampling and satellite-based supervision of vessels costing USD 3 million. (Photo: spc.int)
Country seeks own tuna tagging programme
PAPUA NEW GUINEA
Friday, January 14, 2011, 01:40 (GMT + 9)
Papua New Guinea (PNG) wants to set up its own Pacific Tuna Tagging Programme and will fund a continuation of the work in its exclusive economic zone (EEZ). The programme will be conducted by the Secretariat of the Pacific Community (SPC) and the country’s National Fisheries Authority.
The three-year project will cost USD 3 million and will entail fisheries observers, in-port catch sampling and satellite-based supervision of vessels.
Tagging projects to better understand various aspects of tuna in the Pacific have been done before. The Oceanic Fisheries Programme (OFP) of New Caledonia-based SPC ran a highly successful tuna tagging programme in the Pacific between August 2006 and November 2009 that has achieved 260,000 releases and 40,000 recaptures with the support of the New Zealand Aid Programme, reports Islands Business.
The recovered data informs stock assessments of important tuna species, and its main goal is to sharpen the accuracy of the estimates regarding how much tuna can be sustainably fished and help establish scientifically-based catch limits.
As of July of last year, nearly 15 per cent of all tags had been retrieved; recaptures continue at a variety of unloading points.
|Tuna electronic tagging. (SPS)
Some 4,000 fish stomachs were collected and almost 3,000 Fatmeter measurements made to indicate the condition of the fish. Analysis on about half of the stomachs showed nearly 200 different species out of some 55,000 counted prey.
The SPC’s programme has used almost 1,000 ‘archival tags’ that get placed inside the fish’s belly and trail a pencil-length antenna on their outside. The tags then give precious details pertaining to the tuna’s behaviour, feeding times, depth habits and other factors.
Archival tags are considerably more useful than conventional tags, which offer information on growth, migration and mortality.
Tagged tuna have already been captured as far as 4,500 km from the point where they were originally released, and can show up in locations as far removed as Thailand and Ecuador.
|Skipjack tuna tagged with a conventional plastic tag (Photo: SPC)
SPC scientists have also travelled overseas to form collaborative arrangements with members of the tuna sector throughout the region as part of the follow-up to the main scheme.
Thus far, about 10 per cent of the archival tags have been recuperated and more are awaited.
This represents about 5,500 days of data for the Stock Assessment and Modelling section of OFP, offering insights into tuna behavior including:
- tuna have been found to dive to depths exceeding 1,000 m, possibly to avoid predators;
- to maintain an ideal body temperature, they adjust their depth;
- each species possesses a ‘favourite depth,’ evident as well in their diet; and
- tuna are known to assemble under floating objects; data showed that these tuna remain nearer the surface than those in free schools, such that they become more vulnerable to fishing.
- Pacific tuna still in decline
- Pacific tuna tagging project advances
By Natalia Real