The rise in the number of purse seiners in the western and central Pacific is threatening the future stocks of Pacific bigeye tuna.
In recent years, large scale purse seine fishing vessels, with tonnages ranging from 1,000 tonnes to 4,000 tonnes have been increasing and they have a negative impact on small-size Pacific bigeye tuna because while their main target is the skipjack tuna, purse seiners surround fish schools with seine nets and small-size bigeye tuna are caught incidentally.
Speaking to the Organisation for the Promotion of Responsible Tuna Fisheries, (OPRT), Takashi Koya, the Deputy Director for International Negotiations at the Fisheries Agency in the Government of Japan, said that the rate of increase both for the number of purse seine vessels and the tonnage of tuna caught, have increased conspicuously in recent years.
According to Mr Koya, in 2001, there were 202 vessels, operating for a total of 44,866 vessel days. In 2004, there were 218 vessels operating for 58,762 days. In 2004, there were 226 vessels fishing for 62,314 days.
"Japan has been restraining the number of its large scale purse seine fishing vessels to 35 during the past years in consideration of the tuna resources," he said during the interview. "But there are certain countries or territories that continue to increase their vessels and expand catches without giving any thought to the state of the resources."
The Western and Central Pacific Fisheries Commission (WCPFC) is planning to implement a 30 percent cutback by prohibiting the use of fish aggregating devices (FADs) for three months. These devices easily cause bigeye incidental catch. The WCPFC would also ban the discard of small size fish and would require observers on all fishing vessels.
"Unfortunately, the reality is that the number of purse seiner fishing vessels has been increasing at a faster pace than those measures," said Mr Koya. "The stock management measures will not be sufficiently effective unless the increase in fishing vessels is restrained."
Mr Koya said that it was crucial for developing countries to learn to cooperate with each other to dispel the sense of distrust among them.
"It is a fact that they tend to become allergic to the argument on the management of tunas, considering that advanced countries talk only about the need to control the overall number of fishing vessels but hamper the development of fisheries in developing countries.
"I think it is time for us to discuss ways to reduce fishing capacity while at the same time assisting developing countries in the development of their domestic tuna fisheries."