Friday, June 3, 2011

Fish Kill 101: Government answers frequently asked questions about the event

The Fish Kill incident that hit Taal Lake in Batangas and Pangasinan recently has caused many people to ask whether the affected fish are still safe to eat, what causes the event and other related questions.

To answer those questions, a "Press Briefer on Fish Kill" was posted on the President's website earlier today. Check it out below:

Is the fish safe to consume?

Yes, provided the fish is still on its fresh state condition which should exhibit the following characteristics:
1. Eyes are clear and glossy and not dull and sunken
2. Gills are bright red and not brownish to gray
3. Odor is fresh and not stale or putrid
4. Flesh is firm to touch and not soft; color is not bleached
5. Scales are intact and not easily removed
All spoiled fish, regardless to its species, are not safe to eat and therefore must be discarded.

Why is there a fish kill?

Fish kill results from natural and/or man-made causes. These may include reduced oxygen in the waters which may be due to factors such as drought, algal bloom, overpopulation or a sustained increase in water temperature and pollution caused by man.
In lakes, a natural phenomenon known as water overturn or upwelling occurs as a result of weather or climate changes – from long dry spells to sudden strong rains, among others.

In Taal Lake the causes of fish are as follows:

1. Natural – there is lack of dissolved oxygen in the water due to natural upwelling lakes

2. Man-made – Dissolved oxygen in the water is depleted due to violations of the BFAR’s prescribed Code of Practice for Aquaculture and local government ordinances on proper fish cage management. It was found out that some fish cages had been overstocked and the depths of the fish cage were increased from the prescribed 5 meters to 15 meters. These wrong practices exacerbated the fish kills.

In Pangasinan (Anda and Bolinao)

The fish kill in the coastal waters of Bolinao and Anda are due to man-made causes – improper fish cage management and overcrowding of fish in the cages.

For close water system such as lakes, the prescribed stocking density is 20 fish/cubic meter. For open waters, stocking density could go up to 30 fish per cubic meter or more depending on water circulation among others.

How much fish in these areas were affected by fish kill?

As June 1, 2011 the reported losses are as follows:
Taal Lake: 700 metric tons
Anda and Bolinao: 50 to 70 metric tons

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