Australian authorities last week said they would euthanise around 90 false killer whales which survived a mass stranding on a remote beach in Tasmania. The decision came after experts had announced that it would be impossible to save the whales due to complex conditions.These whales are part of a pod of 157 whales that had beached near Arthur River, in the island’s north west, according to a report by BBC.What is whale stranding and why does it happen?Whale stranding is a phenomenon in which whales are stuck on land, usually on a beach. Other aquatic animals such as dolphins and porpoises are also known to beach. Most of the stranding events involve single animals but sometimes, mass strandings, consisting of hundreds of marine animals at a time, can happen.Mass strandings have been occurring since the times of Aristotle — back then, they were considered a gift from the gods as the stranded whales and dolphins were a rich source of food and oil. However, experts do not know exactly why they take place.In a 2023 interview with The Indian Express, Vanessa Pirotta, a wildlife scientist specialising in marine mammals at Macquarie University (Australia), said, “Whale strandings are a mystery. We do not know why they happen.” The reasons for mass strandings are several, including the topography of the region, illness, human activities, and increasing noise pollution in the oceans.Among the major hotspots for the beaching of aquatic animals are Tasmania, New Zealand’s Golden Bay and Massachusetts’s Cape Cod in the United States. Pirotta explained that these areas witness several instances of stranding possibly because the deep water here quickly becomes shallow due to tidal variations.How might human activities be causing whale strandings?Experts believe that mass strandings could be becoming more common as the health of oceans continues to deteriorate due to human interference. One of the prime reasons for such incidents could be an increase in noise pollution in the oceans.Story continues below this adAlso in Explained | Why Iraq is (slowly) sinking into EarthSeveral studies have shown that noise from large commercial ships, military sonars or offshore drilling severely impacts whales’ and other marine animals’ ability to use sound to navigate, find food and protect themselves. This can drive them ashore by deafening, disorienting, or frightening them.Pirotta said, “For some, this (noise pollution) can reduce the available space to talk to each other. It becomes too loud. For others, it might be a sudden sound that spooks individuals, causing them to rise from the depths at speed.”Another factor could be the rising temperatures of the oceans that cause changes in prey and predator distribution, resulting in whales coming closer to shore.“Whales and dolphins often travel where there is food. Changes in prey movements due to environmental changes like sea temperature and currents may play a role in where whale and dolphin food is located,” Pirotta explained.Story continues below this adCan we prevent mass strandings?It is very difficult to prevent them. Also, as strandings happen due to a host of reasons, no one-size-fits-all solution would work. However, “taking more care of our actions in the ocean to try and minimise human activities which might impact marine life” might help reduce the chances of such incidents, Pirotta said.