In a bizarre and saddening marine event, about one hundred short-finned pilot whales were washed up on the shores of Tiruchendur beach in Thoothukudi, Tamil Nadu earlier this month. Though highly dismaying, this is not a one-off occurrence. Whales can and do get stranded on beaches from time to time; no one fully understands why.
The beached whales in Tamil Nadu
Beached Whales in Tamil Nadu
Over a 15 km stretch of the Tamil Nadu coast, about a 100 whales were washed ashore. Some whales were rescued by local fishermen and put back into the sea before they died. But it is feared that about 73 whales have died as a result of the beaching because of some rescued whales returning to their suicidal course and getting beached once again to finally die.
About 250 more whales were found to be in shallow water, which is life threatening for these deep sea creatures. They were driven back into deeper waters say reports. Marine scientist Velumani of the Fisheries Department has described the incident as unusual and now samples of the whale carcasses have been sent for testing to determine possible causes behind the fatalities.
What causes whales to get beached?
Beached Sperm Whale
Whales use echo navigation (like bats) to find their way around and to travel or migrate. Using these navigational systems, they travel over long distances with remarkable accuracy. However whales do get disoriented occasionally and wander off course and into shallow waters from time to time. It is a phenomenon that has been recorded as far back as 300 BC. The ancient Romans thought that this was the God Neptune punishing the whales for some transgressions.
Sickness or injury to the leader of a group of whales of the loss of a leader could also impact the whole pod or gam, causing them to stray off their usual route. Sometimes following prey or fleeing from predators causes the pod to stray into shallow waters.
What caused the whales to wash up on Tamil Nadu’s shores?
One theory is that the recent earth quakes in Philippines and Indonesia (measuring 6.5 and 6.9 on the Richter Scale could have disoriented the whales. Another theory postulates that unusually low tides and gently sloping beaches could have been responsible.
Manmade reasons for whale disorientation could be SONAR (sound navigation and ranging) low frequency sounds used for navigation by marine vehicles. This could cause not only disorientation but also cause bleeding in the ear and brain tissue of whales. Intensive fishing methods such as trawling, gillnetting and use of long lines could also impact whale behaviours it is thought. Water pollution and toxins could make whales sick. Collision with marine vessels could also cause injury and disorientation.
More results may emerge after about a month when thorough testing is conducted into the reasons for the beaching. Meanwhile the possible reasons for the whales being beached in Tamil Nadu, continues to flummox us.
Author: Reena Daruwalla
