A new research found that noise pollution from ships is disturbing killer whales to a point where it might endanger their actual survival rate.
- Researchers studied the impact of 1,600 ships
- They observed over 2,800 trips of commercial, cargo, military ships and many others
- The high-frequency sounds emitted disrupted orcas’ echolocation
- The higher the speed of the vessel, the bigger the disruption
- For 1 knot of reduced speed, the impact could be lessened by 1 dB
Researchers from the Beam Reach Marine Science and Sustainability School of Seattle conducted a study to examine the effects of ship sounds on orcas in the Salish Sea. It’s potentially an important observation to make as the species is highly endangered. There are already numerous risks the are facing. And, in addition, the killer whale population in the Strait of Juan de Fuca and Puget Sound pose as an exceptional tourist attraction. In fact, earnings from tourism reach millions of dollars.
To better understand the impact of ships on orcas, researchers conducted the study on 1,600 ships of 41 different kinds. This ranged from major commercial ships, to cargo, to military ships. In total, the scientists observed 2,809 different trips. Unlike previous studies, their research focused on high frequency sounds, ranging from 10 Hz to as much as 40,000 Hz and how they might affect killer whale communication or their ability to chase prey.
Orcas are among a string of animals who use echolocation. In essence, their hearing is perfectly attuned to help them detect food, communicate, and navigate through the waters. The clicking sounds aid them in detecting obstacles, as they listen for the sound bouncing off and, in essence, tells them what’s in front of their path.
They can hear up to 20,000 Hz on average, and it’s their biggest weapon of survival. However, researchers found that the high frequency sounds emanating from the ships stretched for longer distances than previously thought. And, implicitly, it’s affecting the orcas abilities to hunt. In turn, the disruption in their tracking technique is detrimental to their hunting capabilities.
According to the researchers, around 50% of the hazardous noises around the Haro Strait were made by container ships and bulk carriers. Military ships, on the other hand, seemed to be the most quiet ones. While all vessels posed as a disruptions, the heavier and larger ships were the ones that caused the biggest disruption. The conclusion was drawn that the faster the ship goes, the bigger the impact their frequencies had on killer whales echolocation.
And, since the 1960s, the noise pollution created by commercial ships has increased tenfold. It further creates a unfortunate situation for the already endangered marine mammals. The only solution offered was to reduce the speeds of passing vessels, especially during crucial summertime periods. During that time, the whales are known to travel within just a few miles of the crowded shipping lanes.
On average, the researchers estimated that by reducing the speed of ships by 1 knot will reduce the damaging impact on the whales’ echolocation system by 1 dB. According to lead author of the study, Scott Veirs, killer whales are at the top of the list as they are an endangered species. However, they will conduct further studies to observe the impact of such ships on other types of fish, invertebrates, and marine mammals.
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