Puget Sound orcas among most contaminated marine mammals on the planet

Scientist from the National Oceanic and Atmospheric Administration (NOAA) in the US have revealed studies that show orcas (killer whales) in the waters around Puget Sound off the northwestern U.S. coast are among the most contaminated marine mammals, with pollutants particularly high in the youngest whales.

This particular population of killer whales numbered more than 140 many years ago but was reduced by half in the 1970s when dozens of them were captured live to be displayed at marine parks and aquariums across the US. Since the 1990s the population has dropped by 20% with only 80 orcas now remaining.

In addition to pollution, a fall in salmon numbers, on which the orcas prey, is another major threat to the whales along with noise pollution and disturbance caused by increased boat traffic in the area.