Posted by: The ocean update | August 12, 2015

From feeding grounds to killing fields : How shipping is threatening the blue whale (Sri Lanka)

The blue whales are in danger from shipping lanes

The blue whales are in danger from shipping lanes

Wednesday, August 12th, 2015 (Stuart Winter). ENDANGERED blue whales – the world’s largest creatures – are being killed in appalling numbers because their feeding grounds have become a major shipping lane.

At least 11 of the supersize cetaceans – measuring 100 ft long and weighing up to 200 tons – have died after being struck by ships but many more may have perished and their huge bodies washed away by the seas. 

Scientists are hoping a simple solution will help stop further carnage for a species that was hunted to the brink of extinction. As few as 5,000 blue whales may still exist, a fraction of the numbers before harpoon guns were invented in the 19th Century by whalers.

Although blue whales are today protected from whaling, they are again under threat from collisions with huge modern ships passing close to the southern coast of Sri Lanka, one of the best places on Earth to see these gentle giants.

Here, the deep tropical waters with their strong upwelling provides perfect feeding for the plankton eating blue whales, but their densest numbers are in dangerous shipping lanes. Eleven blue whales are known to have been killed between January 2010 and April 2012 but the true number could be much higher as winds and currents can carry carcasses off shore.

Researchers estimate there are as many as 1,000 interactions, or near misses, a year in these waters. An interaction is described as an incident where either a ship or whale has to take avoiding action to stop a collision.

The same research has also produced a solution to save the whales. By simply moving the shipping lane 15 nautical miles could reduce the risk to blue whales by 95 per cent.

This conclusion was reached after survey work coordinated by the University of Ruhuna in Sri Lanka, local whale watch operator Raja and the Whales, International Fund for Animal Welfare (IFAW), Biosphere Foundation and Wildlife Trust of India (WTI) over the last two years.

The survey focused on the whale strike hotspot off the coast of Mirissa and provided evidence for a scientific paper, “Distribution patterns of blue whale (Balaenoptera musculus) and shipping off southern Sri Lanka” which was recently accepted for publication in Regional Studies in Marine Science.

Patrick Ramage, IFAW’s global whale programme director, said: “It is not often that a serious threat to whales can be so easily resolved and at minimal cost, but here we clearly see not only the problem, but also a straightforward practical solution which can prevent more endangered blue whales from suffering fatal ship strikes.

“A little more analysis is needed before Sri Lanka can start the process of asking for the shipping lane to be moved, but we are confident that this step will result in a dramatic reduction in the number of fatal collisions involving this great whale.”

Vivek Menon, Executive Director of WTI, added: “Moving the shipping lane this short distance would provide a positive solution for all. It would increase protection for whales and whale watching boats in the area and therefore also help tourism.”

To get the shipping lane moved, the Sri Lanka would have to put a proposal to the International Maritime Organisation. There is proof that moving shipping can help whales. Eight years ago, the shipping lane approaching Boston Harbour in the USA was moved to help right whales and the risk of collision was cut by 58 per cent.

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