Weather-proof fish cages seen as savior of aquaculture industry
ROSARIO, La Union—Marine biologist Al Sobrejuanite was not a bit worried about the fish cages he is tending off the coast of Rosario town in La Union, when Typhoons “Pedring” and “Quiel” left the country through the Lingayen Gulf in September and October.
Like in the past, he was confident that the 20 cages stocked with a variety of high-value fish would not be crushed by huge waves that the successive typhoons induced as they plowed through the gulf.
“Ours are rope-framed cages. They are weather-proof,” Sobrejuanite says.
Again, he was proven right. Not one of the cages was damaged. All 20 were intact and millions of pesos worth of high-value fish saved.
Sobrejuanite’s company, Tiger Property Developers’ Group Inc. (Tiger), is the first to adopt the rope-framed cage technology on a large commercial scale after the Bureau of Fisheries and Aquatic Resources (BFAR) regional office in San Fernando City in La Union developed and introduced it in 2009.
The cages occupy a portion of a 10-hectare mariculture park about a kilometer from the shoreline of Barangay Bani in Rosario. The company grows “pompano” (silver pomfret), “siganid,” snapper, sea bass and “bangus” (milkfish).
“We are new in the fish cage industry at that time and we did not quite know how to go about it. So we sought the help of the BFAR,” Sobrejuanite says. “When the BFAR told us about the rope-framed cage, we immediately fabricated and used it.”
Today, Tiger is the leading pompano distributor in northern Luzon, regularly supplying popular restaurants in the area and Metro Manila. It’s also fabricating rope-framed fish cages, selling them to fish cage operators who have begun to shift to the new technology.
BFAR first tested the rope-framed fish cage in 2008 when its prototype was completed after a year of study.
“We first deployed it in the waters off Badoc, Ilocos Norte, because the underwater current there is strongest. Then we tried it in Rosario, La Union, where the waves are biggest,” says the bureau’s regional director, Nestor Domenden, who led the development of the fish cage.
Fishkills
“These are extreme [water] conditions and the cages have withstood all these,” he says.
The rope-framed fish cage technology, Domenden recalls, was born out of the need to find solutions to the recurrent and devastating fishkills in many fishery areas of the country.
Fishkills occur, he says, because fishing structures have crowded the sheltered mariculture areas, such as rivers, lakes and coves.
“These structures were built too close to one another, preventing the water to refresh naturally, producing water pollutants in the process,” Domenden says. The only solution, he says, was to disperse the fishing structures.
“But the question was: Where do we go?” he says. There’s only the open sea or the exposed areas left for them. The sheltered areas are already saturated.
“And this was how the idea began to take shape. We thought that maybe, there is a kind of material that can be used for fish cages that is flexible enough to withstand the destructive forces of the sea,” he says.
At that time, the most popular fish cage was the Norwegian-type, which uses a circular frame made of polyvinyl chloride (PVC) or steel pipes. Around this frame, which is held by floaters and anchors, a net cage 7 to 10 meters deep is hung and stocks are released and raised inside it.
“We just simply changed the frame of the cage, from PVC or steel pipes, to rope, and hung the same net cage,” he says. “We have thought of the rope because we believed it was flexible enough.”
He was right. When Typhoon “Juan” ripped through Pangasinan last year and Typhoons “Juaning,” “Mina,” Pedring and Quiel battered Pangasinan and La Union this year, the rope-framed fish cages were intact.
In contrast, Domenden says, a fish cage operator in neighboring Sto. Tomas town in La Union, using the Norwegian-type steel frame, had all his cages crushed by the typhoons, losing the stocks to the sea. “This proves that the design, especially the use of the rope, is very appropriate for semi-exposed or exposed areas,” he says.
Aside from its durability, Domenden says, it’s a lot cheaper to build the rope-framed cage because it is simpler. What makes the Norwegian-type frame expensive, he says, is its use of steel or PVC pipes. A rope-framed cage costs half its price.
From their experience with Tiger, Domenden says the rope-framed fish cage has been refined to near-perfection. “We now have better design, better material and it’s now more economical to fabricate it,” he says.
In fact, he says, many industry players have asked him for the details on the design. Fish cage operators in Eastern Visayas have adopted the technology, he says.
Sobrejuanite says at least two big fish cage operators have ordered rope-framed cages from his company. Tiger has applied for patent of the technology and it is awaiting approval.
“On our part, it’s just okay for the private sector to adopt this. They can have it for economic intention as long as they will recognize the source of the technology. We’re [a] government [office] anyway,” Domenden says.
There’s one thing though that he wants to see in the future: Deep-sea mariculture farming using the rope-framed fish cage technology.
“I know it won’t be easy and it will be a bit challenging [for industry players], but it’s very promising,” he says.
