WORK IN PROGRESS:
Fish Kills in Taal
MANILA, Philippines (Xinhua) – The government will assist fish pen owners by providing them milkfish (bangus) fingerlings in a bid to revitalize the hard-hit fish industry in the provinces of Batangas and Pangasinan, a senior government official said today.
Presidential spokesperson Edwin Lacierda said mitigating measures are now in place to restore the quality of water in the provinces concerned.
“The national government will be assisting fish pen owners by providing bangus fingerlings for the restocking of bangus. But this can only be done when the water quality is restored, and can be maintained, to allow fingerlings to develop properly,” he said.
Lacierda called on for a stronger partnership between the national and local authorities to address the impact of the fish kill and to prevent the incident from recurring.
“A triple dilemma at present: the disposal of tons of fish kill; the interdiction of fish kill so that it won’t be sold in public markets; and the revitalization of the industry and the restoration of public confidence in bangus products, requires all concerned to work together and not at cross-purposes,” said Lacierda.
He said the Department of Agriculture (DA) is assisting the national government in enforcing mitigating measures such as lending pumps to aerate the water in Taal Lake in Batangas.
Thousands of tons of fish died in the two provinces due to the changing temperature of water.
Background on Lake Ecosystems
Lentic refers to standing or still water. It is derived from the Latin lentus, which means sluggish. Lentic ecosystems can be compared with lotic ecosystems, which involve flowing terrestrial waters such as rivers and streams. Together, these two fields form the more general study area of freshwater or aquatic ecology.
The general distinction between pools/ponds and lakes is vague, but Brown states that ponds and pools have their entire bottom surfaces exposed to light, while lakes do not. In addition, some lakes become seasonally stratified (discussed in more detail below.) Ponds and pools have two regions: the pelagic open water zone, and the benthic zone, which comprises the bottom and shore regions. Since lakes have deep bottom regions not exposed to light, these systems have an additional zone, the profundal. These three areas can have very different abiotic conditions and, hence, host species that are specifically adapted to live there
Water aeration is often required in water bodies that suffer from anoxic conditions, usually caused by adjacent human activities such as sewage discharges, agricultural run-off, or over-baiting a fishing lake. Aeration can be achieved through the infusion of air into the bottom of the lake, lagoon or pond or by surface agitation from a fountain or spray-like device to allow for oxygen exchange at the surface and the release of noxious gasses such as carbon dioxide, methane or hydrogen sulfide.
Dissolved oxygen (DO) is a major contributor to water quality. Not only do fish and other aquatic animals need it, but oxygen breathing aerobic bacteria decompose organic matter. When oxygen concentrations become low, anoxic conditions may develop which can decrease the ability of the water body to support life.
Aeration speeds up this process of oxidizing organic and mineral pollution. In fact, if there is sufficient aeration, the fish will be able to survive, where before they suddenly died. By pumping compressed air out to the bottom of a lake, lagoon or pond with the use of a diffuser, the rising air bubbles and the friction caused in the water will bring bottom water to the surface where it is exposed to the atmosphere. Large volumes of water thus release noxious gases to the atmosphere, water picks up oxygen while circulating at the surface.
Natural bacteria are stimulated by aeration and circulation and they will feed on muck, organics and the food that normally feeds algae blooms or aquatic plants growth. Using aeration and bacteria is often a safe and sound form of pollution removal.
The need to change consumption patterns
Aeration only address the impact of the reduced oxygen – it does not address the situation which led to the reduction in dissolved oxygen in the first place.
BOLINAO, Pangasinan, Philippines—In an aquarium no bigger than a foot-high box, five goldfish will survive without an aerator when their caretaker provides them a pinch of feed twice a day and a regular change of water.
But try putting 20 goldfish in that same aquarium, feed them a cup of feed daily, do not change its water for weeks and turn off its aerator. Then, pour in cold water. Chances are, the goldfish will die.
This was how Dr. Westly Rosario, chief of the National Integrated Fisheries Technology Development Center (NIFTDC) in Dagupan City, explained how “bangus” (milkfish) cultured in pens and cages in the Kakiputan Channel in Bolinao and Anda towns were decimated recently.
Dr. Edgardo Gomez, professor emeritus of the University of the Philippines Marine Science Institute, said: “[The fishkill was the result of] environmental degradation, with the [structures] exceeding the carrying capacity of the water due to heavy fish stocking and excess feeding.”
Rosario said fish cages and pens in the Kakiputan Channel were stocked beyond the carrying capacity of the water. He said a square meter of fish cage there contained 50 pieces of bangus, exceeding the recommended stocking capacity of 25 pieces.
Worse, the tidal flow in the 2.7-km channel had been obstructed by fish traps laid upstream of the Tambac Bay, as well as by fishery structures at the Catubig area leading to the Lingayen Gulf.
Scientists have been warning authorities that fishery structures, which mushroomed along the Kakiputan Channel in the last 10 years, would endanger the marine ecosystem there.
Extensive use of GIS technology.
Market-driven measures –
- fees on waste – more waste, more fees.
- incentives/deductions on green programs
- Water quality monitoring
Product Labeling Standards to include Source/Origin information(Address/city/province) Date, and Batch.
Review of Water Use Policy, Waste Management Policy, Licensing Process
Find other sources of revenue and job creation.
We can’t keep on handing out fingerlings if they will die as soon as they are released. That’s a total waste of money.