Calming the roar of the world’s oceans

Published in 2008

As shipping expands and whale populations slowly recover in the wake of widely observed whaling bans, collisions between ships, boats and whales are a growing problem. Searching for solutions, however, has taken Michel André, a Laureate of the 2002 Rolex Awards, to the forefront of a rapidly developing new scientific frontier of sound in the sea and to more projects designed to at least measure, and hopefully contain, the raucous, damaging din of humanity.

Collisions between fast-moving passenger ferries and large sea creatures such as whales are causing an increasing toll of human injuries and occasional deaths. More delicate craft such as hydrofoils can be disabled, remnant whale populations are again being put at risk and insurance companies are starting to re-examine their exposure.

Various attempts have been made to reduce the likelihood of collisions between large sea creatures and vessels. Off Boston, in the United States, for example, ships are required to report whale sightings and these are then relayed to other vessels in the vicinity. But the Japanese ferry in which 104 people were injured when it struck a suspected whale off Kagoshima Prefecture in April 2006 was at the time, according to the vessel operator, taking precautions by “transmitting a special sound underwater that whales dislike in an effort to keep them away from the vessel”.

This was no surprise to French biologist, engineer and director of the Laboratory of Applied Bioacoustics (LAB) of the Technical University of Catalonia, Michel André, who has found the hearing of some whales has been so damaged by exposure to human noise that they may no longer be aware of the approaching vessels. In early work on the collision problem in the busy ship and ferry passage between Tenerife and Gran Canaria in the Canary Islands, he briefly considered vessel mounted sonar to detect whales, as well as active warning devices. “But putting another sound in the ocean did not appear the way to go,” he explains.

André played a major role in highlighting the problem of human-generated noise in the oceans after whales were stranded during NATO naval exercises off the Canary Islands. In 2002, he was able to anticipate the strandings and be ready to perform inner ear analysis on freshly dead, but otherwise healthy, beaked whales. The autopsies confirmed the diagnosis of a direct relationship between the sonar sources and the death. “Military sonar and seismic surveys may be among the most intense sound sources, but we also need to be concerned with other constant noises such as shipping,” he says. “There is now not a single space in the oceans that is free from noise pollution.”

André’s Whale Anti-Collision System (WACS) is a passive listening system capable of detecting individual whales – most commonly from their distinctive songs – and giving ships in the area real-time information of their location. Even whales that are not singing can additionally be detected from the reflections their bodies induce in other sounds, including the songs of their companions.

WACS has successfully detected simulated whales in trials. Detecting real cetaceans and communicating their real-time locations awaits a commercial partner and the set up of a full array tuned to the sounds and topography of a specific location. Michel André has no doubt this will occur. Some business investors are already exploring the commercial potential of WACS as a system to minimise damage, down time and injuries.

André also notes the beginnings of regulatory initiatives to protect whales from collisions, with WACS perhaps occupying a key role in the compliance initiatives of leading shippers. The insurance industry is also likely to take an interest in the possibility of reducing its mounting risks by requiring that ships be equipped with anti-collision systems. Some talks have occurred, a business plan is being refined and four areas of possible application are under consideration.

Ironically, one of the potential areas for the trial of WACS could be Massachusetts Bay, the springboard of the “Yankee whaling industry” that spread around the world to decimate whale populations and led to the international whaling ban. The last whaling vessel sailed out of Boston harbour in 1903. In June 2007, Boston shipping lanes were shifted to reduce the danger to the area’s North Atlantic right whales, following 14 known whale deaths in a decade. The other areas under consideration for the trial are Japan, the Canary Islands and the Mediterranean, where André and his colleagues are pioneering the sound mapping of the sea in a project supported by La Caixa Foundation.

A prototype acoustic map, which can be found at www.lab.upc.es/mapa, traces noise levels between Majorca and Ibiza, with ferry tracks and harbour noise showing as a red glow. “We know there is noise, but we do not know what levels can affect the ecosystems,” André says. “Acoustically mapping a problem area is the obligatory first step to developing mitigation solutions.”

In addition to the mapping and acoustic profiling that are now being extended to areas of the Spanish coast, Spain’s science and environment ministries are supporting the development of a noise interaction simulator. “If you understand how anthropogenic noise interacts and affects biological sound sources in specific areas – the sound propagation in water greatly varies depending on the salinity, temperature, pressure, geophysical profile, etc. – you will then be able to anticipate the potential harm or effect of adding another noise source, such as when there is a proposal to conduct seismic surveys in regions where there is a heavy acoustic budget associated to shipping,” André says.

Whole series of new applications of protecting marine creatures from noise are now being developed at the LAB. While the European Commission has made obligatory the use of acoustic “pingers” on fishing nets to deter dolphins from feeding on entangled fish, the introduction of these deterring signals is generally perceived by most cetaceans as a “dinner bell”, often worsening the interaction and definitively contributing to the ocean noise pollution. André and his team thought about the problem and developed a passive system, activated by the dolphin’s acoustic probing that liberates gas bubbles. This is a development of the observation that when scuba divers approach dolphins, the dolphins swim away as soon as the divers breathe.

“We thought for many years that they fled because of the loud sounds of the gas bubble explosions, but we know now that the bubbles reflect their sonar like an acoustic diamond, suggesting they have no way to ‘see’ behind them,” André says.

“Whales and other cetaceans are the bioindicators of the acoustic health of the oceans,” says André. “In addition, in an environment where many other organisms see via sound as an adaptation to limited light, our grinding propellers, thundering hulls, sonar blasts and incessant drilling could have other consequences we are yet to discover.”

To help understand how marine noise has evolved in the past hundred years André and his colleagues have designed a website (www.sonsdemar.eu) where the visitors can listen to whales and dolphins as well as to artificial noise associated to human marine activities.

André believes we have the technology that would make oceans much quieter. Seismic surveys, he says, could map underwater subsurface geology through detecting the echoes from existing ambient ocean noises with only marginally more difficulty than in continuing their reliance on disruptive explosions. As for the much-needed possibility of quieter shipping, Michel André points out that “the technology exists, the military has used it for long, it is neither complicated nor very expensive – we ‘only’ need to draw up some regulations which make it obligatory.”

Phil Dickie

iTunes Channel

iTunes Channel

View and download Rolex Awards videos in iTunes.

Go to iTunes