By Camelia Nathaniel
Sri Lanka’s southern coast is one of the busiest shipping paths in the world and ironically, it is also an area frequented by the fabled blue whales.
In recent times there have been many instances where whales, having crossed paths with a ship’s passage, have been killed- or badly injured.
Marine research scientists say the ship-whale encounters are a leading cause of death among whales around the globe. Many species of this mammoth mammal that are killed are from endangered populations such as the blue whales.
Unregulated whale watching
The problem is particularly troublesome in Sri Lanka, where a largely unstudied population of blue whales, possibly numbering in the thousands, has come under increasing pressure from commercial shipping and from a boom in unregulated whale-watching boats.
With the end of the 27-year long war, tourism began picking up. Whale watching in the south and the east of the country commenced and soon became a major attraction to both foreign and local enthusiasts. However, there are allegations that with the increase in activity around the shipping lines, greater numbers of whales are now being killed.
With the death of a sperm whale just last week off the Kalutara coast, the number of reported deaths of these gigantic whales has risen to seven this year. According to the National Aquatic Resources Research and Development Agency (NARA), the guts of this sperm whale were spilling out of a deep gash on its belly, indicating that it could have been caused by a ship.
In March, a blue whale was found draped over the bow of a container vessel and was dragged into the harbour in Colombo. According to reports last year, some 20 whale carcasses (not all of them blue whales) were seen around the island, as reported by NARA Research Officer, Arjan Rajasuriya. It is not known how many of the deaths resulted from ship strikes on whales. However, researchers believe the numbers reported could be much higher as whales often sink to the bottom of the ocean floor once they are hit.
Harassed by whale-watching boats
Whale researcher Asha de Vos notes that whales are known to regularly swim inside the trajectory of the busiest shipping lanes, lying 15 miles off the southern coast. Some scientists state that the increase in whale watching expeditions could be forcing the whales to seek food farther out at sea, pushing them into the big ships’ path.
According to De Vos, whales are harassed by the whale-watching boats, which could affect their movement.
Available data from several general surveys done in the 1970s show that there were whale sighting at this location, but it was not until the 1990s that interest started to grow. Researchers were particularly drawn by the whales’ tendency to stay around the shallow waters off Sri Lanka all year long; whereas elsewhere, blue whale populations are known to migrate across vast distances.
De Vos started the Sri Lankan Blue Whale Project, a long-term research program, that she hoped will help stop the whale deaths and raise awareness of the whale phenomenon here. For the last three years, from December through May, she has been going out to photograph the whales and uses scientific instruments to better understand their feeding and behavioural patterns.
She claims there must be a reason as to why the whales remain in these waters, but adds that more research needs to be done to find out what the exact reasons are.
In March, De Vos was assisted by a marine lab research team from Duke University, United States. The experts brought along an electronic echo sounder, which uses sound waves to measure the density of prey in the water. For 10 days, she and the team crisscrossed miles of water, taking measurements and finding spots thick with krill.
Better scientific understanding
The aim of her study was to help scientists better understand where and when the whales are feeding and, she hopes, persuade the government to shift the shipping lanes farther out to sea.
De Vos maintains that Sri Lankan authorities need to implement tougher regulations for whale watchers and those who operate these tours—alleging that the tour operators were often manoeuvring the boats around the whales, causing them disturbance.
In countries with established whale-watching industries, laws prohibit getting close to the animals; while the United States sets the minimum distance at 100 yards.
NARA’s Rekha Maldeniya, said that July 2010 through December 2011 there were 15 whale strandings—which is a beached whale or a whale that has stranded itself on land—among them were 13 blue whales, one bryde’s whale and Indo-pacific great whale. So far this year, four sperm whales were stranded while another had been rescued by the Sri Lanka Navy—a total of six incidents by mid-year.
“NARA has observed sperm whales, blue whales and even killer whales in our waters. Killer whales were rarely seen in our waters but recent sightings have been reported. However, a complete study needs to be done to ascertain the environmental changes etc that might be causing these killer whales to venture into tropical waters,” Dr. Maldeniya said. Whale watching on the south coast mainly targets the blue, sperm, and killer whale types, while it is mainly blue whales that are seen on the east coast.
“Unregulated and unmanaged whale watching could have a negative impact on the whale populations. Regulations have been drafted and currently pending Cabinet approval. While whale watching brings in revenue to the country, it cannot be allowed to happen in a haphazard manner as it threatens the survival of the species,” warned Maldeniya.
Increase in incidents
Speaking on the recent reports of increased whale-ship incidents, she said the incidents required close study. While it was not possible to come to a conclusion over the cause, the situation demanded close monitoring.
“We don’t have a clear account of the number of whales in the region though there is an abundant stock of whales in our waters. Last month alone, around 200 blue whales were spotted in Kalpitiya—these whales usually having a preference for the northern waters. Considering the number of stranded whales within the past two years, it is clear that there is an abundance of whales in this region,” she justified.
Environmental lawyer Jagath Gunawardena said that whale watching needs to be regulated in a manner that will not interfere with the whale populations in our waters. “Many whale-watching tour operators are trying to earn a living by engaging in this industry that is currently harming the whale behaviour patterns—forcing them into the commercial shipping path. Regulations must be imposed to ensure the continuity of the species as well as the whale watching industry in a responsible manner. If we don’t regulate and control this activity, all the whales could venture off into more peaceful waters,” he said. courtesy: Ceylon Today