Manila City, 8 June 2009. Tunas are migratory oceanic fishes, which are capable of attaining large sizes. It also includes tuna-like species such as billfish, swordfish, and marlin. In the Philippines, twenty-one species have been recorded. “But only six species are commercially important,” says Dr. Rafael D. Guerrero III, PCAMRD executive director of the Laguna-based Philippine Council for Aquatic and Marine Research Development (PCAMRD).

Among the shallow-water/small tunas, the most commercially important are the frigate tuna or “tulingan” (Auxis thazard), the eastern little tuna or “kawa-kawa” (Euthynnus affinis), and the bullet tuna (Auxis rochei). Most of these tunas are consumed locally.

The important species among the deep-water/big tunas are the yellowfin tuna or “albacora” (Thunnus albacores), the big-eye tuna or “tambakol” (Thunnus obesus), and the skipjack or “gulyasan” (Katsuwonus petamis). These are caught using commercial fishing boats with purse seines and ring nets. Small fishermen catch these species using handlines (hook and line).

Yellowfin tuna is considered as "meat" of the ocean.

Tuna is found in all of the major temperate and tropical oceans of the world. The western and central portions of the Pacific Oceans of the Food and Agriculture Organization (FAO) Statistical Area 71 contain the biggest tuna resources among the world’s oceans. The Philippines straddles FAO Area 71 in which half of the world’s yellowfin tuna is harvested.

“Tunas are caught throughout Philippine waters,” says Dr. Guerrero, “but the most productive fishing grounds are the Sulu Sea, Moro Gulf and waters extending to the North Celebes Sea. Viable tuna fisheries also exist in waters off Western Negros, as well as Northwestern and Southern Luzon.”

Deep-water or oceanic tunas are believed to be breeding in the Moro Gulf when 3-4 years of age. The juveniles (less than one year old) stay in shallow waters (inshore) until they swim out to the West Pacific or Indian Ocean depending on the current. This is the reason why the big tunas are called “fishes without a country.” They have also been referred to as migratory or straddling stocks.

“The Philippines is in a strategic position because of its proximity to offshore fishing grounds,” says Dr. Guerrero, referring to the West Pacific. “It also has an established tuna canning industry and skilled fishermen.”

There’s also the transshipment offered by the Davao Fish Port Complex (DFPC) in Toril, Davao City. A relatively new phenomenon, transshipment is a place where a fishery product may pass through without paying taxes on its way to auction destinations like Japan, Canada and the United States.

“Davao is now a major player in the Asia-Pacific tuna industry because of the transshipment activities taking place here,” said Mario Malinao, DFPC’s manager. “We are exerting all efforts to attract more long-line vessels from South Korea and Vietnam to make Davao a transshipment point. Additional vessels will mean a better outlook for us.”

In recent years, the world tuna industry has undergone remarkable expansion and structural changes. In the 1970s, the five major tuna processing countries were the United States, Japan, Spain, France and Italy. The 1980s saw the increasing participation of Asian countries like Japan, Korea, and Taiwan. Other Asian countries, especially the Philippines, Thailand, and Indonesia, followed suit.

The Philippines, a top tuna exporter.

To outdo other Asian countries, the Philippines employed FAD (Fish Aggregating Device), locally known as payao. “FAD is the most important factor that triggered the phenomenal of the tuna fishing industry,” says the PCAMRD position paper. “The tuna fisheries became the largest and most valuable fisheries in the Philippines during the mid-1970s when payao was introduced.”

As a result, the Philippines became a tuna exporter. “Tunas are marketed worldwide in the international market in the form of tuna flakes, katsubushi, canned tuna, fresh/chilled/frozen tuna, but the bulk of tunas are imported and exported in canned form,” states the PCAMRD position paper. About 95 percent of the major species of tuna are sold and consumed in canned form.

All is not rosy, however, for tuna. The big demand has turned tuna stocks on the verge of depletion. The popularity of Japanese sushi in the western world is putting pressure on tuna populations, turning them into endangered species.

In London, for instance, many sushi restaurants serve bluefin tuna, the world’s most popular fish after the cavier-producing sturgeon. The fatty underbelly of the fish, often on the menu as toro, has become Japan’s cavier and can command prices of up to US$100 a plate.

As bluefin tuna becomes scarce, people turn to other tuna species. “Collapsing bluefin tuna fisheries world wide that supply the high value sushi market are increasing demand for big-eye and yellowfin tuna,” deplored Peter Trott, fisheries program manager of the Worldwide Fund for Nature. “What we are seeing now is an international tragedy where the failure of one fishery adds to the pressure on others.”

The Philippines is a member of the Western and Central Pacific Fishery Commission established by the Convention on the Conservation and Management of Highly Migratory Fish Stocks in the Western and Central Pacific Ocean. It aims to conserve and manage migratory fisheries like tuna.

Compounding the depletion issue is climate change. The Earth’s rising temperature is driving tuna species out of the reach of fishermen, according to Mariano Fernandez, manager of Ocean Canning Corporation in General Santos City.

In an interview with a national daily, Fernandez explained that as tuna are now more difficult to catch, production has slowed down. He surmised the warming temperature of water has been driving tuna species deeper underwater making it difficult for fishermen to catch them. “It’s difficult to catch them because they go deeper. Our fishing nets could no longer reach them,” he pointed out.

The tuna has been commercially promoted as being the “chicken of the sea” because of its commonness and popularity in people’s diet worldwide. Tuna sandwich, for instance, is a mainstay of many restaurants. Tuna meat is rich in omega-3 (polyunsaturated) fatty acids that build up high-density lipids or “good cholesterol.” Consuming tuna is said to be effective in preventing heart attacks.