re: Why do you think the whales are dying near the new windmills in the NE?

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I heard a possible reason is due to the bathymetry surveying activity with low frequency sonar taking place in the area to install new windmills are causing these whales to go deaf. However this kind of ocean surveying is done around the world and we don't see these whale killing issues in other parts of the world.

What's going on?

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Apparently, their eating plastic garbage is the likely cause of death.

It's not possible for directionally-focused multi-beam bathymetric survey sonars to transmit Sound Power Levels (SPL) sufficient to kill a cetacean. The modulation scheme i.e. type of acoustic signal transmitted is relatively low power, and decays by the inverse square law.

Using seismic survey air gun arrays, I suppose it's theoretically possible in near proximity say 100 meters @ 240 dbm SPL, but whales hear them coming and swim away to avoid.

Long ago I did the calcs for an operation involving platform based saturation divers, with two seismic vessels periodically passing by in tandem transmitting source levels of 230 dbm each. The primary acoustic beam pattern was directional in the vertical.

With 80 dbm used as the divers initial threshold of discomfort, the safe closest-point-of-approach was established as 3 kilometers. Could have been a bit shorter but was calculated with abundance of caution in mind.

Wind Farm offshore construction doesn't require large air gun type surveys. And, low frequency (20-100 hz) vibrations and harmonics produced when operational are at low SPL values inconsistent with long range propagation. By long range here I mean 1 kilometer. Not an issue.

I've greatly simplified the ocean acoustic propagation physics involved, search for The Sonar Equation if interested in knowing more.

Avoid Blue Whales, they can ping you with power up to 190 dbm, some 40 db above a jet taking off 25 meters away. That "one ping" you heard during The Hunt for Red October? Yea, don't stand in front of that.

Bottom line, there is no man-made acoustic transmission in the water column near wind farm activity causing whale deaths.

Below is what a bathymetric wide-beam survey generally looks like. There's tons of examples on the web.