Scientists at a scientific meeting of the Western and Central Pacific Tuna Commission (WCPFC) held in Tonga last week concluded that bigeye, yellowfin, and skipjack were all being overfished and in decline.
WCPFC will discuss in December a plan to close four areas of international waters in the Pacific region to all fishing. Greenpeace is asking the New Zealand Government to back the plan, already supported by Pacific Island nations and Australia, to make the Pacific’s tuna fisheries sustainable.
Scientists assessing Pacific tuna stocks may thus advise additional measures to safeguard bigeye and yellowfin stocks. Tuna catches in the Pacific last year beat 2008’s record by 70,000 tonnes – with 2.4 million tonnes.
This means that 58 per cent of the planet’s tuna is now being caught in that region, what Greenpeace calls the world’s last relatively healthy tuna fishery.
Although yellowfin stocks are slightly safer, catches continue to fall and figures are indicating that stocks of skipjack tuna, while healthy, are taking a hit from commercial fishing, Radio New Zealand International reports.
Japan and Fiji both are worried about skipjack populations, which have historically been considered the least threatened and supply 55 per cent of the world’s canned tuna. Japan, Fiji and other southern countries are seeing skipjack numbers in their regions drop.“>
Principal Fisheries Scientist at the Secretariat of the Pacific Community (SPC) Shelton Harley said this is the first time skipjack stocks are suffering from fishing and that, because skipjack is a very important product in Japan’s coastal fishery, it is very significant for that country to be expressing concern. Japan has never before expressed worry about a tuna stock.
This is the sixth consecutive year, he told, with a record high of purse seine catches in the region.
“In the key part of the fishery it looks as though the fishery has reduced the population by about 50 per cent [since the 1970s],” he stated, Radio Australia reports.
Purse seine fishing is problematic because it takes considerable bycatch of juvenile bigeye and yellowfin, particularly when the vessels use fish aggregating devices (FADs). This has led to temporary bans on FADs.
But it is tricky to say exactly what is happening to the tuna stocks.
“One of the common themes when you are talking about maximum sustainable yield and trying to estimate what it is, normally you can’t estimate what it is until you have gone past it,” Harley explained.
“It is one of the main dilemmas of fisheries management. There is always that concern that when you believe the stock is in a healthy state that you might just be overestimating how healthy it is,” Harley added.