BAYOMBONG, NUEVA VIZCAYA, JANUARY 8, 2011 (STAR) By Charlie Lagasca - Tilapia growers in the vicinity of Magat Dam in Ramon town, Isabela have complained that the extreme cold weather in Northern Luzon during the past days could be disrupting the appetite of fish and affecting their normal breeding habits.

Dr. Jovita Ayson of the Bureau of Fisheries and Aquatic Resources (BFAR) for Cagayan Valley, said the cold weather might affect the metabolic processes of the tilapia and lead to loss of appetite and prevent the fish from achieving full growth.

“Fishes have a tolerable temperature range from 18 to 32 degrees Celsius depending on the species. Below or beyond this range, their metabolism is affected. Among these symptoms are loss of appetite, skin lesions and becoming more vulnerable to diseases,” Ayson told The STAR.

The fish growers said buyers refuse to purchase the smaller tilapia at the current rate.

Tilapia, also known as Saint Peter’s fish, normally breeds in fresh water, particularly in shallow streams, ponds, rivers and lakes.

The fish could not breed normally in cool water or cold weather.

Ayson said the ideal water temperature for tilapia growth, survival and reproduction should be between 25 to 30 degrees Celsius.

“Below that, the metabolic rate of the tilapia decreases which causes them to lose appetite, resulting in stunted growth,” she explained.

The current cold weather has forced tilapia growers to sell their stocks even though undersized.

Reports said the cold weather has affected the big tilapia growers at the Magat Dam in Ramon town.

In Pangasinan, the bangus or milkfish and other fish species are also suffering from loss of appetite due to the cold weather.

Dr. Westly Rosario of BFAR said that during the cold season fish become prone to disease and are sluggish, just like humans.

“If it is cold, it’s stressful and abnormal condition to them,” he said.

He added that their spawning is also affected. Since November, there has been no spawning of bangus.

Rosario said spawning is triggered by two factors – the so-called photoperiod or the length of day and night, and the temperature.

He said fishes are raised either in tropical or temperate areas. Fish in the Philippines are warm water species, he added.

“For them in the temperate areas, it’s the opposite. If it’s summer, it’s stressful,” he said.

Rosario said, however, the cold weather benefits other species like oysters because the sudden change of temperature induces them to spawn.

He assured consumers that some fish growers have advanced their breeding process to produce the normal bangus before the onset of the cold months.

Rosario said consumers should expect higher prices of normal-sized bangus and other fish.

“But overall, there would be no drastic impact on the fishery industry particularly bangus,” he said.

He said unlike vegetables that are damaged by frost during cold season because the plants are immobile, bangus and other fish have their own way of moving to areas with warmer temperature. With Eva Visperas

Chilly January: 18.5º in Metro By Helen Flores (The Philippine Star) Updated January 06, 2011 12:00 AM Comments (0)

MANILA, Philippines - Temperatures in Metro Manila and Baguio City dropped to 18.5 degrees Celsius and 9.6 degrees Celsius, respectively, Wednesday morning, the lowest since the start of the northeast monsoon season, the state weather bureau said.

Last year, the lowest recorded temperature in Metro Manila was 18.3 degrees Celsius.

Robert Sawi, weather branch chief of the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), said the cold weather would prevail until February.

Good weather is also expected to prevail in Metro Manila in the next three days. Also, no tropical storm is expected to enter the country this month.

“The cold weather and the strong easterly wind are not favorable for tropical cyclone formation this month, “ Sawi said.

The tail end of a cold front, however, would continue to bring rains over Eastern Visayas and Mindanao until tomorrow.

By Saturday, the cold front is expected to move to Bicol region and bring moderate rains.

Chief News Editor: Sol Jose Vanzi

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