Noise pollution in the ocean isn’t just a nuisance; it has grave consequences for the survival of some marine organisms. A recent study reveals that ship noises make young eels stressed and when confronted with predators, they are less likely to fend off attacks due to impaired escape behaviors, known as antipredator responses.
During exposure to harbor ship noise, young eels were less responsive when faced with a looming predator and showed slower escape behaviors than eels exposed to sounds of the harbor only. And when pursued in a simulated predator chase, they were caught faster than eels exposed to harbor-only sounds.
While humans have explored the oceans for centuries, ship traffic now is greater than ever before, largely because of international trade. Commercial shipping activity—transporting the myriad of consumer goods we have become increasingly reliant on—pervades the oceans. Many of the goods transported by ships may make our lives easier, but these unfamiliar man-made noises can pose a threat to marine organisms. In some cases, the effects could mean the difference between life and death.
Two cargo ships in San Francisco
Image: Line0534 by NOAA – California Publication of the National Oceanic & Atmospheric Administration (NOAA), USA via Wikipedia
Our burgeoning plastic waste—arising from the packaging of everything from food and drinks to toiletries and medicines—isn’t just littering the oceans, it is choking marine life. Almost twice as many endangered green sea turtles are ingesting plastics compared with 25 years ago, according to a study last year, led by Qamar Schuyler, a postdoctoral fellow from the University of Queensland.
But why are foraging sea turtles going after plastic debris? Can they not distinguish between real prey and plastic? Now, Schuyler’s team has found the answers, confirming what scientists have long suspected. Their recent study revealed that sea turtles eat plastic debris mistakenly because it resembles their natural prey; they prefer soft and flexible plastics, such as clear plastic bags that look like jellyfish.
Coral reefs usually conjure up images of pristine atolls teeming with colorful fishes and a vibrant community of organisms, including sharks, living in harmony with each other. For this reason, they are often, aptly referred to as “rainforests of the sea”, and although they comprise less than one percent of the ocean, they are home to a quarter of all marine species.