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Getting out of the way of whales

A fin whale surfaces and exhales a spout of warm air. © Shutterstock/Juan Gracia
A fin whale surfaces and exhales a spout of warm air. © Shutterstock/Juan Gracia

International sea lanes and whales don’t mix, that’s why a group of researchers has worked out a way to keep the two apart, potentially saving scores of lives.

The Western Mediterranean contains around 3 000 fin whales, attracted by the sea’s abundant, small, shrimp-like crustaceans. The area also hosts major sea lanes: 30 % of all international ships ply waters that make up just 0.8 % of the global ocean surface.

Scientists at the European Commission’s in-house science service, the Joint Research Centre (JRC), have been trying to figure out how to evaluate one of the inevitable results of the area’s popularity: collisions, which leave whales dead or injured.

Dr Jean-Noël Druon and Tom Vaes compiled ship locations and movements using the automatic identification-system transceivers now carried by large ships. They also estimated favourable whale habitat (probable positions) using data on feeding habits and movements. Combining this information will, they hope, give policymakers the basis they need to take steps to protect the whales.

Speed limit

One early result could come if the International Maritime Organization (IMO), the United Nations agency with responsibility for the safety and security of shipping and the prevention of marine pollution by ships, takes up a recommendation for ships to reduce their speed in the high-risk areas identified by the researchers.

The project has generated precise data on whales’ feeding habits and their probable locations at different times of the year, allowing scientists to locate more precisely which areas are at high risk, and therefore to give precise recommendations as to where the speed limit should be enforced. Indeed, the report highlights a maximum risk of collision in the Liguro-Provençal basin, between Italy and Spain, during summer time when both the whale habitat is reduced and the maritime traffic peaks, notably with passenger ferries.

‘Limiting ships to a maximum speed of 10 knots in whale-rich areas would drastically reduce the risk of fatal collisions.’

Dr Jean-Noël Druon, Joint Research Centre

The recommendation, which could be presented to the IMO next November by France, Italy, and Monaco under the Pelagos Agreement for the protection of marine mammals, would limit ships to a speed of 10 knots (18.52 kilometres per hour) in the high-risk zones.

‘Limiting ships to a maximum speed of 10 knots in whale-rich areas would drastically reduce the risk of fatal collisions,’ said Druon.

He said that the IMO recommendation, as such, would not have a compulsory character. However, he believes it will still help. ‘Even if we have just a recommendation, at least this will increase awareness,’ he said.

Incident numbers are hard to nail down. A 2006 study of the Mediterranean found that of 287 whale carcasses found between 1972 and 2001, 46 were certainly killed by boats. However, the numbers are likely far greater, with perhaps only one in 10 collisions between boats and whales being reported, experts say.

 Percentage of collisions in the different areas of the western Mediterranean Sea. © Panigada et al. 2006Percentage of collisions in the different areas of the western Mediterranean Sea. © Panigada et al. 2006

Some whale strikes are not even noticed, especially when a larger boat bangs into a relatively small whale. Whales sometimes become lodged on the bulbous bows of large vessels and are discovered only when the ship arrives in port. In the Mediterranean Sea, fatal ship strike was estimated to increase the fin whale mortality by 19 % according to expert analysis.

Fin whales – also called finback whales, razorbacks, or common rorquals – have been getting rammed by boats for centuries, examination of skeletons in museums shows. Today, they are the victims of a quarter of known collisions, according to an International Whaling Commission analysis. At maturity they average around 20 metres in length and weigh 50 tonnes, and they can live to 90 years old.

Collision warning systems

Beyond speed limits, Druon and Vaes’ research could be used to devise other measures. These include collision warning systems for ships and traffic restrictions in popular feeding zones in the Liguro-Provençal basin, such as the Pelagos Sanctuary, an area north of Sardinia popular with whales.

Such moves might be necessary given the continuous increase of maritime traffic. The U.S. National Marine Fisheries Service imposed a mandatory speed limit on ships in an area on the east coast waters, but only about half the ships respected this limit in 2011, after three years of implementation, and about one-third in 2009 and 2010, said Druon.

Reducing speed in the Pelagos area will be more difficult, said Druon: the area is larger and harder to police, and any IMO recommendation may not deter cargo companies in competition to deliver goods fast.

Still, he said passenger vessels might be able to use whale-friendly speeds as a marketing tool reducing both the risk of collision and noise pollution. ‘Ferry companies could use this in a commercial argument, since the associated reduction of fuel consumption may compensate for the decreased number of round trips,’ he said.

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