The study showed that when noises were involved, European eels were 50% less likely to respond appropriately to a predatory threat (i.e., flee the predator), and those that did respond had a 25% slower reaction time. Says study co-author Dr. Andy Radford, "The fact that eels were affected physiologically and spatially suggests that other important functions may also be affected. We focused on anti-predator responses as, unlike impacts on movement or feeding, there is no way to compensate for being eaten after the disturbance goes away." This essentially means that eels are less capable of avoiding predatory fish if there are acoustic disturbances, which could incur an even greater dip in the eel's already scant population.
Since this phenomenon likely affects whole populations, Dr. Simpson asserts that "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."