Marine life enriches the beauty of Sri Lankan beaches and seas and they are home to a vast majority of marine life. But during the past couple of months, it has been quite a debacle for pilot whales, dolphins and turtles. On November 2, 100 pilot whales stranded off the coast of Panadura The Marine Environment Protection Authority of Sri Lanka declares this to be the largest single pod whale stranding in a South Asian country. The MEPA also said that it’s very unusual for such a large number of whales to reach the shores within a short period.
In early October, more than 10 dead turtles were washed ashore on the Colombo beaches and last week, three dolphins were washed ashore at Katukurunda, Kalutara. The Director General, Marine Pollution Prevention Authority, Dr. Terney Pradeep said that the National Aquatic Resources Research and Development Agency (NARA) and the Department of Wildlife Conservation may have obtained samples of the carcasses to ascertain the possible causes of these deaths.
The Director of the Environmental Conservation Trust, Sajeewa Chamikara said, when taking into account the incident of the turtles, it is nothing unusual because sea turtles habitually reach the shores to lay eggs and that they are familiar with the shorelines. However, the Department of Wildlife Conservation has launched an investigation to find out any obscure risks these animals have had to battle with.
Strandings are claimed to be common to a large degree because they can occur at a certain time of the year. This phenomenon is known as ‘cetacean stranding’ when whales and dolphins strand themselves on the beach and the majority of those strandings result in death. Even if a precise explanation as to why they reach the coasts cannot be given yet, scientists assume that stranding happens because of the highly sociable nature of these animals. Cetacean strandings have gone down in history: in 1946 in Argentina, 835 false killer whales stranded on the beaches and last September, in Tasmania, more than 400 whales were spotted on the beach.
Background
The earliest recorded pilot whale stranding was recorded in 1918 in Chatham Island, New Zealand where 1000 pilot whales stranded on the shores. But according to Sajeewa Chamikara, this is the first instance where such a large number of marine animals, especially pilot whales stranded on the beaches of Sri Lanka after 20 pilot whales stranded on the Eastern Sampur coast on May 31, 2017.
Consequently, the recent stranding is a real jolt to our conscience about what we will otherwise soon lose track of.
Pilot whales are estimated to grow up to 20 feet long and weigh a ton. In Sri Lanka, short-finned pilot whales are the often-observed whale species. They are known as ‘cheetahs of the deep sea’ for their deep, sprint dives and quick pace. Both dolphins and whales reside in deep waters yet, as Sajeewa Chamikara says, dolphins also reside in lagoons such as the Kalpitiya and Puttalam ones.
Whales are a genus which lives in ‘pods’ or the social groups of whales. Usually within these pods, they protect one another, travel and hunt together. If one from the pod strays close to the shoreline and gets pushed towards the beach by the waves, the others will also follow. Sometimes, if one whale calls for help on reaching the shore, there is a possibility of others coming to the coast and getting into trouble. According to arachnologist, conservation biologist and co-founder and principal scientist, Biodiversity Education and Research, Ranil P. Nanayakkara, tooth whales are more prone to stranding, as they use sonar to navigate and forage for food.
Both whales and dolphins navigate via ‘echolocation’ (using sound propagation to navigate) which is the technique of emitting sounds to the environment and listening to the reverberations of those sounds which return from objects near them. The dolphins and whales use these reverberations to locate and identify objects around, to find their way through them and to seize their prey.
Whales breathe from their blowholes located on the top of their heads. If they are stranded on the beaches, it becomes difficult for them to keep their blowholes unblocked since they cannot stay upright lying on the beach. If they lie on the beach for hours, they will be near death by collapsing under their own weight, succumbing to dehydration and the obstruction of their blowholes.
Possible causes
Speaking to the Sunday Observer regarding the possible causes behind the phenomenon, Ranil P. Nanayakkara said that they cannot ascertain the cause of the deaths without conducting a necropsy (autopsy). He also spoke about the stranding records maintained by him and his team which reveal that there is a clear peak during this time of the year, especially August to date. He said military sonar exercises are carried out. (exposure to mid-frequency military sonar).
Sajeewa Chamikara also said that presumed pitfalls for these animals can be prominently in the veering of the paths of the sea currents which subsequently may lead to ir stranding on the shores. “Radars,naval exercises and joint missions too can perturb them when they usually dive in the deep sea. The sea constructions leave a huge impact on the swerves of the sea currents” As Sajeewa said, the changes in the atmospheric pressure levels and basically the climate changes veer the patterns of sea currents. Sea constructions have by and large caused coastal erosion (Panadura to Negombo and Kochchikade coastal line comprising 1270km), changes in wave radiation and ramifications in ocean systems which are interdependent, Sajeewa said.
The Director of Species Conservation and Project Manager of the Tree Society of Sri Lanka, Pubudu Weerarathna said, there is a serious issue as to why such a number of marine animals embraced death during the last couple of months. “Fishermen have complained about an unusual green colour in the water, which we suspect to be a form of algae.
We still cannot say whether it is linked with the recent deaths of marine animals, he said. He is not sure whether the responsible authorities have done the postmortem of these animals. According to Weerarathna, NARA, the Department of Wildlife Conversation and the Department of Fisheries are the institutions t which are in charge of probing this incident.
Injuries
Apart from what is predicted so far a spate of marine animal fatalities can be a single turn – out of a series of events such as blast fishing (also known as dynamite fishing), changes in water temperatures, geomagnetic disturbances, hunting too close to the shore, infection and sickness due to old age. These are natural and environmental causes (except blast fishing) which may not be relevant to the recent incident.
All the environmental officials who spoke to the Sunday Observer said that no external injuries could be observed in the carcasses of the animals. Pubudu Weerarathne said that the deaths can be a consequence of shock created by a soundwave. “Generally, these animals get dehydrated, exhausted and damaged by the sand reefs, stone reefs and coral reefs. Also, their lungs and internal organs get mangled and become weak,” said Sajeewa. Aside from these complications, they may also suffer disorientation, hemorrhage in ear, lungs and jaw fat, gas-bubble lesions, fat embolism and decompression sickness.
Legal measures
Under the Flora and Fauna Protection Ordinance, these animals are protected species. If investigations pertaining to these tragic deaths of marine animals prove any type of human conduct to be accountable under Section 30 of the Flora and Fauna Protection Ordinance, the Fisheries and Aquatic Resources Act, and as per the Maritime Law, legal measures can be taken against the culprits for killing, attempting to kill and possessing parts of these animals.
The health of the marine environment determines a considerable part of the food chain. The precious lives of these animals too are invaluable! Getting alienated in an unfamiliar domain would be traumatic and ghastly to all living beings including us, humans. Therefore, let’s contribute to the protection of the natural system, be responsible for our part on Earth and the rest will be taken care of by the environment itself.