Noisy, acidic oceans harmful to whales

Environment News Service: Oceans and seas are becoming noisier with more vessels, increased seismic surveys for oil and gas, off-shore construction and recreation, and a new generation of military sonars, an alliance of wildlife groups said today. They warn that the cacophony is intensifying threats to marine mammals that use sound to communicate, forage for food and find mates.

The groups, attending the United Nations Environment Programme's Convention on Migratory Species conference in Rome, are urging governments and industry to adopt quieter engines for ships, tighter rules on the use of seismic surveys, and new, less intrusive sonar technologies by navies.

At the conference, the International Fund for Animal Welfare issued a report, "Ocean Noise: Turn it Down," showing that the distance over which blue whales can communicate is down by 90 percent as a result of intensified noise levels.

The largest animals on Earth, blue whales are vulnerable to noise and ship strikes. This blue whale died in September 2007 in the waters off Santa Barbara, California. (Photo courtesy Santa Barbara Museum of Natural History)

Ship noise in the Pacific Ocean has doubled every decade over the past 40 years and the global shipping fleet is expected to double in size by 2025, after doubling between 1965 and 2003, the report calculates.

Airguns used in seismic surveys generate "colossal" sounds peaking at up to 259 decibels and can be repeated every 10 seconds for months. These sounds travelled more than 3,000 km from the source. There are 90 seismic survey ships in the world, the report states, and a quarter of them are in use on any given day…

Engraving of a beached whale by Dutch artist Jacob Matham. Apparently made after an engraving by Hendrick Goltzius.