inbriefs

Are earthquakes responsible for beached marine animals?

New Delhi, January 13 (G’nY News Service): Scientists are of the opinion that just as earthquakes cause fatalities in the human world – it also causes disorientation in marine mammals leading to beaching and eventual death. This aspect is probably what was responsible for the recent happening where beached whales off the coast of Tuticorin in Tamil Nadu was seen in scores. However, commenting on nomenclature, Dr. Jai Bhaskar, Senior Scientist in Central Marine Fisheries Research Institute (CMFRI) pointed out that the stranded whales were not ‘true’ whales but instead part of the oceanic dolphin family known as Delphinidae, named Short Finned Pilot Whales.

Short Finned Pilot whales are deep sea mammals. They are related to Long Finned Pilot Whales which are similar in size and shape. Dr. Bhaskar said that the most likely cause for the stranding could be an earthquake that occurred four days ago, off the coast of Indonesia. This is not the first time such a stranding has taken place he added. In 1973 on Jan 14th,147 such dolphins were found stranded on the same beach.

On Monday evening,12th Jan 2015, around 81 Short Finned Pilot Whales washed up on Manapad beach in Tuticorin district on the Eastern coast of Tamil Nadu. Around 45 whales died on the beach while the rest were towed back with the help of local fishermen and authorities.
Most marine animals stranded on beaches are mammals. Mammals are more susceptible to strandings as they require a certain depth of water to survive and cannot survive on only land or shallow water. Mammals who display highly social behaviour are more likely to be a part of a mass stranding. A mass stranding consists of more than one marine animal in the same geographic location and generally in the same tidal cycle. An exception to a mass stranding is when a mother/calf pair are stranded. Sea turtles can also get stranded due to a variety of natural and human reasons.

Scientists say a lot of marine animals get stranded intentionally or unintentionally. Whales, dolphins and seals get regularly stranded due to both manmade and environmental reasons. Injuries from ships, being shot and getting entangled are some of the major manmade reasons for beaching which have been identified by scientists. Other man made reasons include pollution which can make whales and dolphins sick and confusion due to manmade sonar which can disorient whales. Natural reasons which can lead to stranding of marine animals are diseases, poison from various aquatic species, changes or abnormalities in the Earth’s magnetic field, earthquakes, trauma caused by various elements in the sea, old age and changes in weather.

Another reason for getting stranded that researchers say are attacks by predators. When being pursued by predators whales or dolphins will move to shallower waters where the chance of getting stranded is higher. Some predators such as killer whales strand themselves intentionally on beaches to get access to prey such as seals.

In this case however, scientists allude to the most probable cause being the earthquake and highlight the need to help them get back into the water as early as possible.

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