Friday, July 18, 2008

Technology to Sense Whales in the Water

Recently, after looking at the flashy Fred Olsen Express web page, I decided to re-read the following recent academic report:

A couple of things I noticed. There is a significant, reported or documented fatal vessel-on-whale strike in the Canary Islands every few months. They have noticeable increased since 2002 with 3 fatal strikes, 2003 with 8 fatal strikes, 2004 with 6 fatal strikes, 2005 with 6 fatal strikes, 2006 with 5 fatal strikes, and 2007 with 9 fatal strikes. There are a number of high speed vessels operating there. I compare that to Hawaii over the past year where I have not heard of a single documented and reported fatal whale strike yet. Does this mean that there have not been any or just that they were not known to have happened or that they just weren't reported? I don't know, but it is an interesting point to ponder.

The other point mentioned at the end of that academic report is Passive Acoustic Monitoring (PAM). When I look that up, there are some interesting articles, and this reminds me of some sort of related funding that Congress may have approved in the past few months. About the articles, here are the most interesting ones I found:
"Award Winning Technology To Protect Whales From Ship Strikes"

"Once prey to an industry that hunted them almost to extinction, whales today face a new threat – violent encounters with ships and pleasure craft. French biologist Michel André has pioneered a groundbreaking system to prevent collisions between whales and sea-craft." Julian Cribb reports.

"The unlucky passenger who died when a high-speed ferry rammed into a sperm whale in the Canary Islands was the world’s first known victim of a new form of pollution – ocean noise.

Worldwide, the number of ships and pleasure craft that come into collision with large sea creatures is climbing inexorably – and the insurance bill with it – as numbers of both vessels and whales multiply and the sea-lanes become more crowded. The cause of the accident, says marine biologist and Rolex Awards for Enterprise Laureate Michel André, most probably lay in damage to the whale’s sensitive hearing apparatus caused by the rising roar of man-made noise throughout the oceans. The whale was stone deaf – and simply didn’t hear the ferry coming in time to avoid it.

Burgeoning Sea Traffic Deafening Marine Wildlife

What no-one expected when commercial whaling ended was that whale numbers would one day rebuild sufficiently to become a hazard to sea craft. But in places where marine traffic is heavy, vessels fast and whale numbers expanding, crashes are increasingly common. Where the ship is large the whale comes off second best, but in the case of cruisers, yachts and smaller vessels, damage can be mutually serious - even deadly.

We often speak of the ‘silent deep’, but the exact opposite is true. Sink a few metres into the ocean, and light begins to fade. At 40 metres you enter endless night, where eyes are of little use and hearing is all. Here, noise moves five times faster - and much farther - than on land. High frequency sounds decay rapidly but low frequency noise can travel right around the planet using a special ‘sound channel’ in the oceans, centred about a kilometre down. The oceans are the true realm of sound.

Most sea creatures – from whales and dolphins to fish, squid and shrimps – respond to sound, and many produce it. They use it to hunt and to avoid the hunters, to find mates and food, to guide schools of fish, to navigate, to send messages and transmit warnings, to establish territories and warn off competitors, to stun prey and deceive predators, to ‘illuminate’ their surroundings acoustically, to avoid obstacles and sense changes in water and conditions.

They click bones and grind teeth. They use drum-tight bladders and special sonic organs to chirp, grunt, sing and boom. They belch gases and liquids. They vibrate special organs or their entire bodies. They gather to form great choirs. Sounds emitted by sea creatures span the range from 0.1 hertz to 300 kilohertz.

Far from the ‘silent deep’, the oceans are a raucous uproar.

Into this age-long tumult, in the blink of an evolutionary eye, has entered a new thunder: the throb of mighty engines and the thrash of propellers as 60,000 huge vessels plough the world’s sea lanes; the hammer of diesels and scream of outboards as 4 million fishing boats and more than 10 million ferries and pleasure craft surge to and fro; the thump and ping of military and fishing sonars; the deafening crash of seismic ships seeking oil and gas; the blare of acoustic harassment devices; the grinding of drills and dredges; the low-frequency growl of scientific experiments designed to monitor global warming.

Scientists report that background noise in the ocean has increased 15 decibels in the last half-century and 1000-fold since the industrial age began. This is enough, scientists say, to mask and scramble the normal sounds of ocean life going about its business. Dr Michel André, for one, is convinced the human uproar is killing whales – and now, apparently, people too. ‘One of the major short-term and worldwide threats for the sea and marine mammals is constituted by the noise produced by artificial sources,’ he says.

In the Canary Islands between six and ten whale collisions a year were being reported, mainly by fast ferry services. When a passenger died after a high-speed ferry rammed a basking sperm whale, André, a marine acoustics expert at the University of Catalonia, was asked to investigate. He decided to start by studying the dead whales. The first two he examined showed severe damage to their inner ears. They were, in short, deaf to certain sounds.

‘The inner ear lesions we found in sperm whales came from two resident whales which died after collisions. These lesions affected animals of different ages,’ he says, indicating the damage is due to an external factor, not to aging.

The injuries also occurred at a place in the ear’s sensitive structure corresponding in frequency with the sounds emitted by shipping. To test whether the wider whale population was affected, his team ran controlled exposure experiments on 215 sperm whales in the Canaries in which they played sounds in the same low-frequency range as the affected regions of the ears. The whales failed to react..." See rest of article at: [About the writer: Julian Cribb is a well known Australian science writer. He was science Editor at The Australian, has won more than 30 awards for journalism and is Adjunct Professor of Science Communication at the University of Technology Sydney.]

Other good articles on PAM include:

Efficacy of passive acoustic monitoring for marine mammals set to ...
Of all of the mitigation effort and expense that's been placed on the seismic industry, it's Passive Acoustic Monitoring (PAM) that simultaneously holds the...

Ketos Ecology Passive Acoustic Monitoring (PAM)
Passive Acoustic Monitoring (PAM) is increasingly used as a marine mammal ... mid-frequency Seiche and Ecologic towed arrays to monitor sperm whales...

Passive Acoustic Monitoring Systems .... PAM probably makes the biggest contribution in detection of sperm whales principally because they can be detected ... - Online Magazine Article: Special Focus - Dec-2007
NMFS also requires seismic operators to visually monitor the water surface for 30 min. or, in times of low visibility, use Passive Acoustic Monitoring (PAM) ...

Aloha, Brad

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