We have long witnessed the damage that we, as humans, have inflicted upon the natural existence of wildlife and the consequences, in some cases, are irreparable. However, we rarely consider how our noise pollution disturbs the existence of marine life. A new study highlights how orcas are severely affected by standard ship noise.
With only a few of them still left, the killer whales are generally considered on the brink of extinction. They are not on the list of endangered species yet, however their existence is fragile, as they are surrounded by a multitude of threats, both natural and anthropogenic.
These types of whales have existed since the beginning of mankind, but with an increased human population and the constant need for diversity, our activities have come to seriously affect their habitat.
The killer whales are said to have first appeared 11 million years ago, but now out of the many factors that threaten their existence, excessive noise is one of the most important ones. Why is that an issue you may wonder?
Since orcas use echolocation in order to find and catch fish, the underwater noise that comes from ships and oil tankers could very well be disrupting their communication with other species, making it impossible for them to find food.
In this extensive study, which was conducted for 28 months, between March 2011 and October 2013, scientists have measured the noise frequency and volume coming from approximately 1,600 ships, while they were passing through Haro Strait, in Washington State.
The researchers focused on this area in particular because this is where we find the most endangered population of orcas.
Since this species uses mid and high frequencies in order to send signals to other fish, the team of analysts focused on a wide variety of frequencies, spanning from 10 Hz to 40,000 Hz, so they can determine exactly the level of impact that can occur.
The study’s main researcher Scott Veirs of Seattle’s Beam Reach Marine Science and Sustainability School explains how they have included listening devices inside the natural habitat of the orca population and their findings clearly showed that ships are indeed responsible for interfering in the communication between killer whales and their prey, making their survival all the more difficult.
It is worth mentioning that from all the vessels analyzed, container ships revealed the highest median levels of noise, while military ones showed some of the lowest.
One solution that is presented by the team of researchers is for the vessels to simply slow down. The information indicates that any decrease in a ship’s speed by 1 knot reduces the noise levels by 1 dB.
Image Source: PETA