Ship Noise Shown to Affect Whales’ Dining Habits

     (CN) — Humpback whales’ ability to feed is often disrupted by low-frequency noises from passing cargo ships and freighters, a recent study finds.
     While getting struck by a ship is an obvious concern for whale populations, the sounds of these vessels — and their effect on whales — is often overlooked.
     A team of researchers examined the foraging behavior of 10 whales around the Gulf of Maine and found they descended more slowly in the presence of ships, limiting their opportunities to find food. The whales also performed fewer side-roll maneuvers, a technique they use to eat a type of fish called sand lance that’s found near the sea floor.
     “Overall, I was kind of surprised that we were able to detect any response statistically just because these humpback whales are very adaptable,” said Hannah Blair, a graduate student at New York’s Stony Brook University who led the analysis on the data.
     Sound is vital for marine life, as they rely heavily on communication during searches for food.
     The new study adds to a growing body of scientific evidence in recent decades that suggests noise caused by humans is hurting marine life, which can mask sounds produced by prey and distort the prey’s behavior.
     In July, the National Oceanic and Atmospheric Administration announced a project to address noise that negatively impacts marine life over the next 10 years. The agency’s goals include “minimizing the acute, chronic and cumulative effects of noise on marine species and their habitat” and educating the public about the issue.
     The researchers’ findings represent the first evidence that noise could be disrupting the feeding behavior of humpback whales.
     “They’ve been having to put up with this for decades probably. It’s another warning that we do need to be very concerned about noise in the oceans because we don’t know the impacts,” said David Wiley, a co-author of the study and a NOAA research coordinator.
     The team used an acoustic tag with underwater microphones and multiple sensors to study 10 whales in and around Stellwagen Bank National Marine Sanctuary between 2006 and 2009.
     The researchers collected data from 218 dives by the whales and found that nearby ship noise reduced the number of their side rolls by 29 percent per dive. The noise also limited the whales’ descent rates by 14.5 percent and their ascent rates by 12.8 percent.
     G.M. “Hans” Thewissen, an anatomy professor at Northeast Ohio Medical University, compared the findings with a spoiled dining experience for humans. Thewissen was not involved in the study.
     “If you sit at a black-tie dinner and someone blows a tuba in your ear, you might get up and leave. Same with the whales and the ship,” he said. “The critical question next is how badly it disrupts the dinner of the whales.”

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