Dr. Ziro Suzuki, Tuna Scientist
The state of the stock of bigeye tuna has not been improving in a desired way. The principal cause of this situation is that the catch of bigeye by purse seine fishing vessels has not been reduced. It was in 2009 that the Western and Central Pacific Fisheries Commission (WCPFC) launched on regulations of fishing, centering on the restriction of purse-seine operations using the Fish Aggregating Devices (FADs), and reduction of catch by longline fishing vessels. The prohibition period of the use of FADs was set for two months in 2009, the first year of the introduction of the regulation. It is to be extended to three months in 2010-2011. But the catch of bigeye by purse-seiners outside the FAD prohibition period remained the same as in the period before the introduction of the measure. As a result, no effects of the regulation have been obtained.
In the regulation of bigeye catch by purse-seine vessels, member countries are entitled to choose from either (1) no-fishing during the FAD prohibition period or (2) the regulation to reduce their catch. All members except Japan and the Philippines chose no-fishing during the FAD prohibition period. Japan chose the reduction of catch by30%, which ensures the reduction of catch volume because Japan has a sampling system designed to grasp accurately the catch volume of juvenile bigeye caught incidentally in purse-seine operations. From 2011, however, all the countries agreed to take concerted actions to comply with the 3-month prohibition of FADs as regulations of purse-seine fishing. With respect to longline fishing, on the other hand, the regulation is designed to reduce the catch by 30% by gradual steps over a span of three years. In this regard, regulations are at least being complied with.
Japan is abiding by the established catch regulations both for purse-seining and longlining. But FAD regulations for purse-seine fishing by other countries did not generate the anticipated effects. FAD operations have high fishing efficiency, and the efficiency has been enhanced year by year. Even if prohibition is enforced for a few months, no limit has been imposed on catching bigeye outside the prohibition period. As the catch of small-size tunas cannot be curtailed, there is no benefit for longline fishing that catches large size fish. Rather, longline fishers alone are put at a disadvantage because their catch quotas are even more reduced. FAD fishing operation is primarily aimed at catching skipjack, but at the same time it catches incidentally the immature bigeye and yellowfin tunas.
To the present, efforts have been made to explore ways to reduce the catch of immature fish of these two species, without reducing the catch of skipjack. But no effective methods have been found.
In part of the purse-seine industry, there appears to be a move to level up the discovery rate of fish schools not aggregating around floating objects, etc. (called “sumure in Japanese) by using a helicopter in anticipation of reinforcement of FAD regulations in the days ahead. It seems that the right course to be taken is to advance toward enhancing the rate of successful catch in fishing targeting schools not aggregating around floating objects in the future. Drastic extension of FAD prohibition period, including total prohibition of the use of FADs, will become a central agenda at the WCPFC meetings in the future.
It should not be overlooked here that overcapacity, especially overcapacity of purse-seine fishing, exists in the background of this issue. Present potential capacity of purse seine catch exceeds grossly the current catch that should be reduced. While the need to reduce the overcapacity is seriously debated on one hand, purse-seine fishing efforts are actually increasing, on the other.
Japan’s proposal to freeze the number of purse-seine fishing vessels, tabled at the WCPFC annual meeting last year, gained considerable number of supporting views as a general approach, but at the same time, a number of issues were raised in relation to its implementation. It was unfortunate that the proposal was not adopted because time for debate ran out. The solution of the issue of overcapacity has a basic importance, and the reinforcement of FAD regulation can be viewed as an issue derived from it.