January 17, 2006
Tahong (mussels) saves bolinao bangus
The “tahong” (mussels) saves the day for this town’s bangus industry which is beset with problems like polluted waters and high cost of commercial fish feeds.
Lawyer Virgilio Solis Jr., a bangus (milkfish) fish cage operator, said many operators have resorted to tahong culture because of several reasons such as the high cost of feeds and high cost of fingerlings.
Many operators could no longer afford the high cost of inputs and fingerlings while the market price of bangus is low so bangus culture is not very profitable anymore, Solis said.
The poor condition of seawater brought about by the bangus industry itself, also results in high mortality of the cultured fish.
So many operators abandoned their bangus cages and are now into tahong culture, Solis said.
Another bonus of mussel culture is that tahong thrives in contaminated water and they act as cleansers of the sea. They actually feed on organic matters such as excess feeds given to the cultured bangus.
So the sea gets cleaner, the bangus can thrive better and the residents are earning,” Solis added.
Mussels were not known to be endemic to the town but somebody must have introduced the species that soon proliferated.
Solis said fish cage operators used to be irritated with the mussels which cling to and destroy the nets. But soon found that the shell food culture could be a profitable venture.
“So they put up bamboo poles alongside the cages and so the tahong culture in Bolinao was born,” Solis said.
Except for the cost of the bamboo poles and labor, the tahong culture operators do not have to spend for feeds so the expense is minimal. Each bamboo pole costs 50 pesos (P30 for the pole and P20 for handling and setting in the sea), a minimal expense compared to thousands of pesos for a cage structure.
Solis explained that for every 1,000 bamboo poles, an operator can harvest 6,000 sacks of tahong every six months. At 200 pesos each sack, the operator earns a cool P1.2 million every harvest.
There are areas in the water off Bolinao town which were designated for tahong production. “Practically all bangus operators are engaged in tahong industry,” Solis said.
Still, the production is short of the orders from traders and retailers from different provinces, he added.
Comments
January 19, 2006
Simon Francis Blaise R. Vistro said:
Before bangus (milkfish) fish cage operator rush and exchange their fish nets into bamboo poles for “tahong” cultivation. It would be enlightening to read some facts about the said shellfish.
The Philippine green mussel or “tahong” as it is locally known is the only species of mussel farmed commercially in some areas in the Philippines. It is known scientifically as Perna viridis.
P. viridis is commercial important because of rapid growth rate and high population densities (Rajagopal et al. 1997). The green mussel is also a good candidate for cultivation because reproduction can be induced throughout the entire year (Sivalingam, 1977; Coeroli et al., 1984). The mussel can also be transplanted from one environment to another with little adverse effects(Parulekar et al., 1982).
Salinity tolerance: The high growth rate of the green mussel is related to high salinity and an abundance of phytoplankton(Chatterji et al. 1984). According to Sivalingam (1977), the bivalve has a 50% salinity tolerance between 24 and 80 ppt. The green mussel has a high tolerance for reduced salinities, increased survival during atmospheric exposure, and high survival rates in turbid water (Morton, 1987).
Temperature tolerance: Chatterji et al. (1984), also demonstrated that growth was significantly affected by temperature. According to Sivalingam (1977), between temperatures of 10-35°C the green mussel is 50% temperature tolerant.
The bivalve has also been used as an indicator of biopollution of heavy metals, organochlorines, and petroleum hydrocarbons (Bryan, 1976). According to Philips (1980), and IOC (1981), P. viridis is one of the best mussel species to test for biopollution.
The impact potential of a species is expressed in terms of their actual (or potential) impact to human health, economic and environmental impacts. P. viridis has been categorised as one of ten potentially most damaging species. The potential international target species are prioritised by their location in the invasion potential/impact potential space. P. viridis has been categorised as 'High priority'. (Hayes et al. 2005)
Threat to humans: They can be carriers of diseases and parasites harmful to native species. P. viridis has also been recorded with high levels of accumulated toxins and heavy metals and is linked to shellfish poisoning in humans.
Personally, this is a cause of alarm rather than an applause for the apparent economic benefits because “tahong” is not known to be endemic in the waters of Bolinao. Their proliferation and species adaptation in the area would mean that there is high pollution in the waters of Bolinao (due to irresponsible Bangus fish culturing?).