ANGELES CITY, Philippines – Experts from the Philippine Institute of Volcanology and Seismology (Phivolcs) yesterday ruled out the possibility that an underwater earthquake sent hundreds of melon-headed whales fleeing to the coast of Pilar and Abucay, Bataan last Tuesday.
More than 300 melon-headed whales, cetaceans of the oceanic dolphin family also known as electra dolphins, invaded the coastline of Bataan province, nearly stranding in Pilar and Abucay towns. Melon heads usually gather in large numbers and often strand together.
“Dolphins are not among the animals known to react to earthquakes,” Dr. Jane Punongbayan, Phivolcs supervising science specialist, told The STAR yesterday.
She said no earthquake has been recorded in either the Bataan or Subic area in the past days, although a magnitude 2.4 tectonic earthquake was recorded at about 8:11 a.m. yesterday, with its epicenter noted some 17 kilometers northeast of Tagaytay City.
Punongbayan said yesterday’s tremor was felt at Intensity 3 in Lipa City in Batangas and Intensity 2 in Calamba, Laguna, adding that an earthquake in the area of Bataan and Subic would usually be felt in Metro Manila.
She said there is no historical record that shows that dolphins react before, during or after earthquakes, unlike other animals such as frogs, snakes, cows, and pigs, among others.
Punongbayan cited the case of Haicheng City in northeast China where damage was minimized during a strong earthquake on Feb. 4, 1975 because of warnings manifested by local animals as early as January.
She said unusual behavior of animals intensifies before an earthquake.
Before the strong tremor hit many parts of China in May last year, thousands of frogs were seen on the streets of Mianzhu two days earlier.
A few hours before the earthquake occurred, zebras were seen banging their heads against walls, elephants swinging their trucks wildly, lions and tigers, normally asleep at midday, walked tirelessly around, and peacocks started screeching in a zoo in Wuhan City.
However, Punongbayan said there is no correlation that can be established between the dolphins in Bataan and earthquakes.
Earlier, Dr. Mundita Lim, director of the Protected Areas and Wildlife Bureau (PAWB) of the Department of Environment and Natural Resources (DENR), said veterinarians from the Ocean Adventure in Subic Freeport and the bureau are studying the dolphins’ ears to determine the cause of their disorientation that led them to surface in Bataan.
Members of the Philippine Coast Guard, fishermen, and other volunteers eventually drove the dolphins back to the open sea.
Looking for reasons
Meanwhile, veterinarians and representatives of Ocean Adventure, World Wide Fund for Nature (WWF), UP Institute of Environmental Science and Meteorology, and PAWB agreed during a meeting with DENR Secretary Lito Atienza that dynamite fishing could be a reason for the disorientation of the dolphins.
Dr. Lemnuel Aragones, of the UP Institute of Environmental Science and Meteorology, said acoustic trauma, which can be caused by sudden and powerful explosions that often lead to damaged ear drums, among others, could be due to dynamite fishing or sounds emitted by passing ships as well as seaquakes.
However, Aragones has ruled out seaquake as the cause of the dolphins’ massing up off the coast of Pilar town.
Lim, for her part, had not ruled out acoustic trauma, and added that veterinarians had taken tissue samples from the dead dolphins for further study, specifically to determine the presence of toxic substances, at a laboratory in UP Los Baños in Laguna.
She also said that experts would still have to observe another infant dolphin that was recovered alive trapped in a fishnet Tuesday afternoon off the coast of Abucay.
“Histopathology (would be done) to provide more insights into the cause of death or other exposures of the animals. Also what is being looked into here as a whole is whether there is an indication of a bigger environmental problem,” she added.
Dr. Rafael Guerrero, executive director of the Los Baños-based Philippine Council for Aquatic and Marine Research and Development, however, suspects that climate change could have caused the dolphins’ erratic behavior.
“It is possible that sea currents are changing because of climate change. There is something in the ocean that we should know about,” Guerrero said, adding he would conduct further studies to validate his theory.
Atienza, meanwhile, said Bataan Gov. Enrique Garcia Jr. admitted during the meeting that dynamite fishing still exists in some parts of Bataan waters.
“He confirmed. In fact, he said they were battling it… they were campaigning against it,” Atienza said. – Katherine Adraneda, Evelyn Macairan, Helen Flores, Raffy Viray