Tuna resource
conservation

The yellow fin tuna is the most important tuna species in Philippine marine waters. It occurs mostly in the Suluwesi Sea, and the major landing site for its fishery is General Santos City in southern Mindanao. This species has been heavily exploited during the past 35 years. Tuna fisheries, consisting mainly of three species, have been one of the major sources of economic wealth of southern Mindanao. There is a large export of yellow fin tuna to Japan, and negotiation is going on for the export of this species to the European Union and the Islamic countries. This demand for tuna could ensure the continued economic development of the country particularly southern Mindanao.

But there is a problem: Philippine tuna resources are over-exploited. One report, according to my informant, states that at the present rate of exploitation the yellow fin tuna stock will disappear by the middle of this century. This and other species are now relatively rare or exist in much reduced numbers in our southern seas. Tuna fishers now fish far out into the Sulawesi Sea in the vicinity of Indonesian islands and even farther away toward New Guinea. The reason: Not enough fish for commercial purposes in Philippine southern seas.

I think that the prediction of future collapse of yellow fin tuna fisheries is sound, considering the facts about tuna exploitation. If there are skeptics, I would like to remind them of the sudden collapse of the cod fishery in the early 1900s.

Tuna fishermen who are concerned with the sources of their wealth have recommended some measures to prevent the predicted collapse. One measure is to direct exploitation to large individual fish by the use of selective fishing gears. They argue for the use of hand-lines with single hooks designed to catch only large fish, sparing small individuals and allowing them to grow to large sizes before they are fished.

They further argue for the banning of other gears that are non-selective such as long-lines, ring nets, baby seines, and especially those using super-lights. These gears catch juveniles and rare species, and may be considered anti-conservation in terms of their effects on the fishery resources.

There are some 3,000 hand-line fishers in the General Santos area. Government fishery regulators should listen to them.

To these recommendations I would like to add that the use of fish aggregating devices such as "payao" and resource-destructive gears such as beach seines, and small mesh nets of all kinds be banned. Two important papers by well known fishery scientists have implicated the "payao" as one cause of fishery depletion because it facilitates the catching of juvenile fish, including those of yellow fin tuna. Beach seines definitely catch fingerlings of tuna and other pelagic fish (such as barracudas) and coral reef fish. This can easily be verified. For example, my graduate students studying fish in Bayawan City fish market reported juveniles and fingerlings of tuna and barracuda being sold there.

I am told that fishers using the resource destructive gears mentioned above cheat by presenting large-mesh nets when confronted by fishery regulators, but revert to their bad practice of using fine-mesh nets when these officials are no longer aboard fishing vessels. This must be going on because how else can one explain the presence of small fingerlings and juvenile fish sold in fish markets?

In summary, fishery authorities must take aggressive steps to conserve our tuna.*