Environment, Europe, Headlines

ENVIRONMENT-ITALY: Whales Can’t Hear Love Songs of Potential Mates

Francesca Colombo* - Tierramérica

GENOA, Italy, Mar 26 2005 (IPS) - The whales inhabiting the waters off Italy’s Liguria coast are in danger of remaining forever ”single” because severe noise pollution is drowning out their mating calls.

The area known as the Ligure Sea, which comprises the Gulf of Genoa and the northern Tirreno Sea in the Mediterranean, is considered a sort of ”whale sanctuary”, but the daily merchant ship traffic causes so much noise that it has become nearly impossible for the giant water mammals to communicate with each other.

Found in these waters are fin whales (Balaenoptera physalus), a species of baleen whales, which have sieve-like plates instead of teeth, used to filter krill, plankton and small fish.

The males emit certain sounds to attract the attention of females, who indicate whether they are ready for mating, ”especially in the winter months, and with greatest volume and frequency in February and March,” Fabrizio Borsani, a marine acoustic researcher with the Rome-based marine research institute, ICRAM, told Tierramérica.

The whale ”song”, which sounds something like hammer strikes, would be heard up to 500 kilometres away if there is no interference. But the female whales in the Ligure Sea don’t hear the males’ call, ”and there is a danger that they will be left single,” said Guido Ognone, research coordinator at the Genoa Aquarium.

An ICRAM study conducted between 1999 and 2003 found that the Gulf of Genoa and northern Tirreno Sea are among the world’s noisiest marine areas due to ship traffic, especially merchant vessels.

Some 300 tanker ships alone pass through the area each year, carrying 18 million tonnes of petroleum and its derivatives to northern Europe.

ICRAM recorded 16,000 hours of whale song, using 18 devices with micro-computer chips placed at depths of 600 to 2,000 metres, and found that on a daily basis the sounds from ships interrupt 97 percent of the whales’ messages.

According to the researchers, that means that every 24 hours there are only 43 minutes free of noise, not enough for the whales to finalize their mating communications.

The fin whale can measure 24 metres long and weigh 60 tonnes, with a lifespan of around 90 years. Its strong musculature allows these undersea giants to swim at a rate of 40 to 50 km per hour.

Hundreds of whales inhabit the Mediterranean Sea, and spend most of their time alone, covering hundreds of kilometres each day.

The reproductive capacity of the baleen whales is relatively low, with females producing an average of three offspring in a lifetime. Females are ready to become mothers at around age 14, and males are sexually active beginning at 18.

The gestation period ranges from 12 to 16 months, and mothers nurse their young for one year. The baby whales consume some 200 litres of milk daily.

Faced with the ”noise explosion” of the last century, much of it resulting from more and bigger ships, ”it is possible that the whales have increased the volume and frequency of their song, but that remains a hypothesis to be tested,” said Ognone.

In any case, it is clear that noise pollution is harmful to the sea’s inhabitants, and is why United Nations and European Union agencies are seeking ways ”to limit human activities in the sea, but there have been no results nor changes in direction,” Maria Teresa D’Agostino, head of the marine campaign for LAV, an Italian animal rights group, said in a Tierramérica interview.

According to ICRAM, to prevent further harm to whales, it is essential to regulate ship traffic in the navigational corridors, establish preferential routes, and build vessels, ports and other infrastructure that reduces noise pollution.

The World Wildlife Fund reports that a quarter of whale species are in danger of extinction. The populations where decimated by hunters in the past centuries, and continue to be threatened by toxic substances in the seas and oceans.

Furthermore, the International Whaling Commission estimates that 300,000 whales die each year, trapped in fishing nets. The whales off the Liguria coast face all of these threats.

(*Francesca Colombo is a Tierramérica contributor. Originally published Mar. 19 by Latin American newspapers that are part of the Tierramérica network. Tierramérica is a specialised news service produced by IPS with the backing of the United Nations Development Programme and the United Nations Environment Programme.)