Eels are losing the fight to survive when faced with marine noise pollution such as that of passing ships, according to a study published in the journal Global Change Biology.
Scientists from the Universities of Exeter and Bristol that found that in the presence of ship noise, European eels (Anguilla anguilla) were 50% less likely to respond to an ambush from a predator, while those that did had 25% slower reaction times. Those that were pursued by a predator were caught more than twice as quickly.
Lead researcher Dr Steve Simpson, Senior Lecturer in Marine Biology & Global Change at the University of Exeter, said: “Our findings demonstrate that acute acoustic events, such as the noise of a passing ship, may have serious impacts on animals with direct consequences for life-or-death behavioural responses. If these impacts affect whole populations then the endangered eel, which has seen a 90% crash in abundance over the past 20 years due to climate change, may have one more problem to deal with as they cross busy coastal areas.”
When scientists played recordings of shipping noise to eels, the fish had higher stress levels and reduced right-left preferences.
The study highlights the importance of assessing the scale of impacts of the noise that now pervades many coastal environments.
The European eel is classified as ‘Critically Endangered’ by the IUCN Red List of Threatened Species. As well as noise pollution it faces loss of habitat, physical barriers to migration, problems with parasites and over-fishing.
Simpson, S. D., Purser, J. and Radford, A. N. (2014), Anthropogenic noise compromises antipredator behaviour in European eels. Global Change Biology. doi: 10.1111/gcb.12685
Photo credit: David Perez (CC BY 3.0)