Motor-boat noise makes fish bad parents, leading to the death of their babies

Date: June 6, 2017

Source: University of Exeter

Noise from motorboats is making fish become bad parents, and reducing the chance of their young surviving, research led by marine experts at the University of Exeter has shown.

The sound of motorboat engines disturbed coral reef fish so acutely it changed the behaviour of parents, and stopped male fish properly guarding their young, feeding and interacting with their offspring.

The research, which involved playing recordings of natural reef noise or intermittent motorboat noise around 38 fish nests over 12 days, found that the death-rates of baby fish exposed to boat engine noise increased significantly, with six of the 19 boat-noise nests suffering complete mortality.

The Exeter University led team of marine biologists say that noise from boats is a 'global pollutant', distracting fish and making them unable to properly protect their young from predators. They believe motorboat noise should be factored in when trying to protect fish stocks and manage fisheries.

Dr Steve Simpson, an expert of the impact of noise on marine life at the University of Exeter.

"This study raises important implications for managing the noise of the 100,000s of motorboats used around the world in coral reef environments. We are now considering acoustic quiet zones and corridors, and exploring how engine and propeller development can reduce the impact of this globally prevalent pollutant."

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As oceans warm, coral reef fish might prefer to move rather than adapt

Date: October 5, 2016

Source: University of Texas at Austin

Scientists have new evidence that coral-reef fish -- who are capable of adapting to warmer temperatures brought about by global climate change -- will probably opt instead to relocate to cooler parts of the ocean.

In experiments using a fish found in coral reefs around the world, the blue-green damselfish, Chromis viridis, researchers found that the fish were capable of adapting to living in water 2-4 degrees Celsius above their normal summer temperatures; however, when given the slightest chance, the fish moved to cooler water.

"When fish have to adapt to increased temperature, there are physical consequences. They may not be able to handles stress, or reproduce, or even grow," said marine scientist Dr. Jacob Johansen from The University of Texas at Austin. "But, when they seek out temperatures that they've evolved to be in over thousands of years, they can mitigate the impact of increasing temperatures and not sacrifice critical physiological processes."

Johansen and fisheries biologists from the University of Copenhagen and James Cook University collaborated on the study, published in the journal Global Change Biology.

Marine fish are faced with a tough decision. The ocean is warming at a faster rate than occurs on land, because oceans operate as sinks -- trapping in the heat. Many ocean fish will need to adapt or move to avoid death.

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