Unchartered waters: Exploring the unknown

By Vimukthi Weeratunga

In the days past from the medieval Vikings that chartered the mighty oceans to the sophisticated ocean-going vessels of today, man has always been linked to the ocean and its riches. Written references of marine mammals date back to the 2nd century AD with pre-historic descriptions of whale hunting as early as 1,000 BC. The said whale hunting, essentially a struggle of survival in history has now turned into a bloodbath and a gruesome sport in the high seas; unseen and mostly unheard (Folkens 2002).

The cetacean family includes whales, dolphins and porpoises and bear the same characteristics as all other mammals, yet specially adapted to living all or part of their lives in the oceans. To keep warm at sea, most of them depend on a thick layer of fat also known as blubber, which also streamlines their designs enabling them to swim faster. Many species can stay submerged for a long time, while surfacing is a must to breathe. To be able to stay under water for long periods, they store extra oxygen in their muscles and bloodstream. They also have more blood than land mammals in proportion to their body sizes, and can direct their blood flow to only their vital organs such as their heart and lungs, while being able to slow their heartbeat thus using less oxygen during deep dives.

Aeons ago, much akin to man that evolved from apes, the whales were known to be land creatures that resembled dogs and more closely related to the hippopotamus. Known to have evolved into ocean life about 60 million years ago, these ancestors quietly adapted to survive solely in the ocean. Their front legs evolved into paddle-shaped flippers, they lost their back legs, their tails grew larger and widened to form flukes, and they developed a thick layer of fat, called blubber, to keep warm in the ocean. They also evolved with skulls elongated and nostrils shifted to the top of their heads (blowholes) to aid in breathing at the ocean’s surface. Although these gentle giants spend all their lives in the ocean, they carry much resemblance to humans, being warm blooded, possessing the ability to give birth to their young, nursing them and possessing of minute traces of fur. This is further signified by their necessity to come to the surface to breathe through their lungs (Zimmer 2001).

With the passage of time, the anatomy of the whale changed. It adapted to diving with specialised organs in order to store more oxygen in their blood. There are two parvorders of whales; toothed and baleen whales. Separated around 34 million years ago, the toothed whale (odontocetes), as aptly named, has dental organs with one blowhole. There are over 73 species of toothed whales worldwide, including sperm and beaked whales, belugas and narwhals, porpoises and dolphins, and even fresh water dolphins that live in rivers. They range in size from the 60-foot (21.1 m) sperm whale to the 5-foot (1.5 m) vaquita. Treated as an introverted family member of the mostly eccentric tooth whale family, the beaked whales spend most of their time in the deep and are rarely encountered by explorers; it is why new species are yet being discovered. True to their character, some beaked whales bear odd features with only the male population blessed with teeth.

As somewhat whales, a lively pod, the tooth whales like bats, use echolocation or sonar to detect objects in their environment. They produce sounds through air passages in their heads, which are projected out in front of them. The sound bounces off solid objects and echoes so the animals are able to generate an “image” of what is around them; a phenomenon that has attracted much attention and research. Many species, such as the humpback and sperm whales, seem to have individually identifiable calls. Orcas (killer whales) live in groups or pods and each pod has a dialect or accent, just like humans have accents depending upon which part of the world they are from.

The baleen whale parvorders (mysticetes) include 11 species ranging in length from the pygmy right whale at 21 feet (6.4 m) to the largest whale, the blue whale at 100 feet (30.5 m). Baleen whales have two blowholes and instead of teeth, have hundreds of rows of baleen plates, which are made of keratin. Most baleen whales feed on krill (shrimp-like animals) or small fish. Right and bowhead whales feed in a slightly different way, which is called skimming. Water and food flows through a gap in the front of their mouth where the baleen is missing and the food gets trapped in the baleen fringe while the water flows out between the baleen plates. Even though baleen whales eat very small shrimp, which are low on the food chain, these whales are immense and eat great quantities at once. For instance, the blue whale is the largest animal on earth, weighing up to 150 tons, its estimated to eat 4-8 metric tons of tiny shrimp each day (Folkens 2002).

Diving into the depths

Cetaceans play an important role in stabilising the marine food chain and reproduction of other species through a benign form of geo engineering, participating in a trophic cascade (from the top of the food chain and tumbling down to the bottom of the food chain). Whales and dolphins help regulate the flow of food by maintaining a stable food chain, controlling the population of certain animals. Cetaceans are well known for their high level of intelligence, behaviour, echolocation, communication and environmental impact. This has led to a lot of discoveries and advancements regarding sonar, aquatic environments, marine life/biology and animal intelligence/behaviour and other important oceanic topics. Our growing understanding of them is important for improving conservation measures of all marine mammals as well as improving the oceans ecosystem (Berta 2002).

The maritime zone of Sri Lanka is inhabited by 30 species of marine mammals. Though the existence of marine mammals in the waters surrounding Sri Lankan was known since the 14th century with the writings of historical travellers, official scientific explorations began only in the 1980s. Therefore, what is known about the diversity, ecology and conservation of marine mammals is based on information gathered by research carried out during the last three decades. The 30 species of marine mammals recorded in Sri Lankan waters are classified under two groups, cetaceans and sirenians. Whales, dolphins and porpoises belong to cetaceans while manatees and dugongs belongs to sirenians. Cetaceans in Sri Lankan waters include 29 species of whales, dolphins and porpoises and sirenian has only dugong (Yapa and Ratnavira 2013).

Sri Lanka’s location, marine topography with deep ocean canyons and weather systems has created very hospitable conditions for marine mammals to thrive in our waters. Narrow continental shelf, averaging of about 22km, often close to the shore, concentrates the island’s plankton-rich water that attracts cetaceans. This makes Sri Lanka one of the best places to observe ocean giants in shallow water. During the past decade, Sri Lanka has gained a reputation as a treasure trove for whale and dolphin watching, both among local and foreign tourists mainly due to the spectacle created by the innumerable cetacean species. 

The most commonly sighted cetacean around Sri Lanka is the blue whale - the largest animal that ever lived on our planet. Second most commonly sighted whale is the sperm whale, the largest toothed mammal. Records of larger pod of sperm whales in Sri Lanka’s waters suggest that deep sea canyons are healthy enough to provide enough food sources to sustain large numbers of sperm whales. Mirissa, Kalpitiya and Tricomallee became hotspots to watch whales and dolphins with less effort. However, at present there are no regulations in place to control or monitor the whale watching industry and as such it may pose a major threat to the marine mammals, especially the larger whales. 

Lessons learned from other countries indicate that poorly regulated whale watching can leave deep craters on the marine mammal populations. As Sri Lanka plans to expand its tourist industry, marine mammals can prove an important economic resource as it can be marketed as a major tourism experience, heightening the necessity of conservation (Ilangakoon 2006 and Martenstyn 2013).

Transgressions of a superior race

The commercial value placed by the early adventurers and voyagers set the looming predicament of whales in motion. ‘Whale oil’, as mentioned in the famed novel Moby Dick, is the oil from the blubber of whales that was heavily traded and used for many purposes such as lighting, makeup, meat, pet food or even sinews for tennis racquet strings. A waxy substance called ambergris, found in a sperm whale’s digestive system, was used in perfumery. Ambergris was very valuable and a large lump found by a beachgoer was worth a fortune. 

Since 1986, there has been a commercial ban on hunting large whales for commercial purposes. However, the mindless slaughter continues in the name of science and monetary gain despite rising questions of the irony of hunting the animal to understand its existence. Certain Native American tribes are still allowed to hunt whales for subsistence. These hunts are regulated with specific rules for the method of hunting and yearly quotas that limit the number of whales taken.

With the fate of the dolphins and porpoises lying in the hands of fishing nets and abandoned trash on the ocean floor, the elevated toxins in the waters only diminish the immunity and sustenance of these creatures. Other species also suffer from the loss of habitats. Even well-loved past-times such as whale watching can also harass them, especially if the boats venture too close to the whales or separate the mothers from their calves. Small whales are sometimes captured for display in hotels, aquariums etc. this further detriments the quality of life of these creatures. In certain parts of the world, these whales are hunted and served for consumption.

The biggest threat to the marine mammals inhabiting the oceans around Sri Lanka is posed by the fisheries industry. Large numbers of dolphins and dugongs are killed annually both directly and indirectly by fisherman. In addition, increased shipping traffic, marine pollution by both land-based and marine-based sources, and habitat destruction, especially shallow habitats such as sea grass beds, are the other major threats faced by marine mammals. 

Even though Sri Lanka’s maritime zone is nearly eight times larger than its land area, there is a major discrepancy in the allocation of areas for conservation as evidenced by existence of only four Marine Protected Areas in Sri Lanka as opposed to more than 100 protected areas declared on land. These four protected areas are primarily aimed at conserving coral reefs without considering the protection of cetaceans (Ilangakoon 2006 and Martenstyn 2013).

Popular movements around the world have helped whales to expand their population. Unfortunately their threat is not completely eliminated. We need to understand and solve some of the problems currently threatening whales like climate change, boat strikes, entanglement in nets, and noise pollution. It is by understanding the issues and generating more awareness that one can contribute to conserve and help save these magnificent animals of our oceans. To observe them at sea can be a life-changing experience and for those lucky few with the good fortune to see these animals at sea are truly blessed to cherish such moments forever.

(This article first appeared in ‘Living Free’, a 196-page book of wildlife photographs by two of the country’s best-known shutterbugs Chitral Jayatilake and Vimukthi Weeratunga.)