On the night of January 11, a couple of whales washed up on the shores of Kulasekarapatinam at Thoothukudi in Tamil Nadu. The fishermen immediately rushed them back to the sea before they died. But by Tuesday morning, just a few kilometres away at Manapadu in the same district, 86 whales were on the beach, of which 45 have died. Fishermen and experts rushed to rescue of the ones which survived.
This is not the first time something like this happening, and whales are known to wash up on the shores on both the coasts of the Indian peninsula.
So why does this happen? We spoke to Dr Jiyalal Jaiswar, Director-level scientist at the National Institute of Oceanography about it.
The ocean-bed closer to the shore in Thoothikudi is shallow, and the shallow section of the ocean-bed is very narrow by that coast.
Every day, there are two cycles of flooding and ebbing by the shores. During flooding, water gushes into the coast, and when it is ebbing, the water is receding fast away from the shores.
Dr. Jaiswar explains that whales have the nature of moving against the wave. So during the ebbing period, when the water is receding fast from the shores into the ocean, the whales are moving towards the coast. If they get too close to the coast, and the water recedes too fast, they end up landing on the shallow shores with no room to swim.
This is known to happen on the Western coast as well, but the shallow section of the shores are narrower on the south TN coast.
This is a worldwide phenomena and there are other reasons too. Brenden Borrell writes in the Scientific American,
Statistically, we are only able to determine the cause of a stranding in about 50 percent of all cases worldwide. In some cases it is obvious, like a ship strike leaving an animal in poor condition. In the northeastern United States pneumonia is a common cause of stranding. We see other diseases and trauma, such as shark attack on whales or dolphins or attacks by members of the same species. Poisonous "red tides" will also affect marine mammals. Some strandings have been speculated to be related to anomalies in the magnetic field.
Whalefacts writes that “Another common concept adopted by some marine biologists and scientists is that man-made sonar may be interfering with a whales echolocation and/or natural brain wave activity causing whales to become disoriented or sick forcing them to flee towards shallow waters where they end up beaching themselves.”