It seems we humans are responsible for yet another nature problem, since killer whales cannot communicate because of ship noise. The information comes from a new study that proves that this also affects the hunting abilities of the marine animals.
Many of you have probably never given thought to underwater sound pollution because it is rarely put in the spotlight. Sound pollution created by passing ships through coastal habitats interferes with the echolocation of the killer whales, affecting both their chances of finding food and of communicating with each other.
Since we cannot give up on ships, scientists tested sound levels that are dangerous to the animals. In order to do this, they chose a shipping lane and sent out clicks, while observing the echoes of the sounds through the water. The results were not favorable. It appears that over the last fifty years the commercial shipping has increased so much that the low-frequency noise has a ten times higher frequency than it did in the 1960s.
Therefore, the ship noise that is emitted at the same frequency of the orcas is surely disrupting their lives and thus their survival chances. The researchers went even further and thought of other species that might be affected in the same way. As a result, they analyzed the higher frequencies used by tooth whales. By making the same test in the Haro Strait in Washington, they reached the conclusion that some ships can reach higher frequencies and thus affect the other whale species.
According to Dr. Scott Veirs, co-author from the School of Marine Science and Sustainability Beam Reach, the frequencies measured by the scientists are between 10 and 40,000 Hz, quite a wide range. Killer whales use the 20,000 Hz frequency.
It seems that military vessels have the lowest levels of noise, while container ships present the loudest frequency below the 20,000 Hz level. Since ships do affect marine wildlife that inhabits shipping lanes, the best thing to do is equip commercial ships with a quieter technology, or have them slow down when entering and passing through well-known marine sites. The second option might work since if a ship slows down by one knot, a broadband noise level is also reduced by one decibel.
As killer whales cannot communicate because of ship noise, we have another problem on our hands that we need to solve. It remains to be seen whether commercial actors can be persuaded to take measures for protecting wildlife or if they will be as careless as in all other incidents.
Image Source: True Wild Life