Shipping isn’t what it used to be. The romance of wind propelled vessels exploring the high seas is a thing of the distant past. Today, the surface of the word’s oceans are a platform for a massive, multi-billion dollar transport industry. This computer generated image shows the extent of shipping traffic coverage over the word’s oceans and gives a sense of the sheer scale of the enterprise.
Now consider the size of each individual cargo ship and the frequency of their passage on a particular rout. If you’ve ever marveled at size of a cargo ship on the horizon, you may also have noticed that it’s soon followed by another, and another.In-fact; there is a constant stream of them passing the horizion, day and night all year round!
Each of these massive ships produces underwater noise pollution; sound that travels great distances under the sea and that combines to form a continuous background din.
Press play to hear what it sounds like. Cargo-Ship-at-20-knts (Source: ©Thomas R. Kieckhefer, http://www.savethewhales.org)
This noise is produced from their engines, propellers, generators and bearings and falls withing the frequency range of 20-300Hz which is sadly the same range used by whales.
It has been long known that sound is critical to whales for their very survival. Whales use sound for navigation, finding food, finding a mate, avoiding predators and for communicating directly with each other.
Sadly, increasingly, they must do so in competition with human made underwater sound of which shipping noise is only one contributor.
Imagine if your immediate neighbour insisted on using a generator or electric broom 24/7. Imagine how much harder it would be providing meals for your children, talking to your partner, watching TV. Now imagine that constant noise multiplied by every house in your street. This is what ocean animals are having to contend with and unfortunately a substantial cause of our Ocean’s rapidly diminishing health.