Friday , April 27, 2018

Dagupan milkfish susceptible to 'thermal shock'

MILKFISH growers in Dagupan City were alerted amid the seemingly abnormal weather condition prevailing these days when a sudden downpour comes after a hot summer day at a time when the temperature usually reaches above 40 degrees centigrade.

City Agriculture Officer Emma Molina, however, reported that despite this abnormal situation that occurred since after the Bangus Festival ended on May 6, no force harvesting was noted in Dagupan yet.

Aquaculture scientists dubbed this kind of situation abnormal, which is a bane to fish in captivity and likely to bring thermal shock, leading to mass fish kill, Molina said.

She said nature was kind though, as the sudden abrupt rains come in the afternoon or early evening when water from the sea was entering the rivers and into the fishponds because of high tide.

With the colder water from the sea entering the fishponds, no thermal shock on the fish has ever occurred, said Molina. She, however, called on the fish farmers to open the gates of their ponds once high tide comes to let the colder water comes in.

In this hot weather, Molina called on fishpond owners and their caretakers to be always observant always.

She told them to watch out for signs of thermal shock, such as when the fish reach the water surface with their nostrils first.

This is also a sign of lack of dissolved oxygen in the water, so there is a need to undertake some interventions in order to save the fish, she added.

When these signs come, force harvesting is necessary if fish farmers do not want to incur more loses, which they surely will if the fish will die in the water, Molina said.

The city agriculture officer said they have started advising local fish farmers to do something to prevent the effect of thermal shock because of the prevailing abnormal weather.

Molina said the most vulnerable to thermal shock would be the bigger milkfish or those already within marketable sizes.

She also admitted that during hot weather condition, the growth of milkfish was usually slow. (PNA)