What Warning Signals Does Nature Give Us?

Scientists are always looking for signals in nature that tell us about the human impact on the environment. They take measurements of water quality or air quality. They watch the fate of certain tell-tale species - the survival of polar bears, the changing migration of birds, the reproduction of tiny benthic creatures in river bottoms. These are barometers of the health of our eco-system.

That’s one reason why endangered species attract such attention – not just for their own survival but also because if they are in danger, that says something is wrong with the eco-system, something that may eventually come back to haunt human beings.

The Orca whales in Puget Sound are an endangered species. They an enormous tourist attraction because of their dramatic black and white coloring and their playful antics. But they are also a valuable scientific indicator. Like humans, they are at the top of the food chain and so they accumulate the contaminants that get into the environment.

These Orcas make Puget Sound their home. They’re known as “residents.” So they reflect the general health of Puget Sound. Their residence has enabled marine biologists to know them well, literally by name. Scientists have watched families of Orcas travel together, have charted family trees, recorded babies being born and older whales dying off in their sixties or seventies, after a life-span much like humans.

What alarms specialists like Ken Balcomb, Director of the Center for Whale Research, is that younger whales are dying, too – “dying way before they even mature,” says Balcomb. “The population is declining. Probably the next twenty years we’ll be witnessing the departure of this population.”

Scientists at NOAA, the National Atmospheric and Oceanic Administration, have been sampling Orca whales for clues to their increased vulnerability. NOAA has been shocked by the high levels of PCBs and other toxins found in young whales, passed along through mother’s milk. Other scientists have established that Puget Sound seals and King Salmon - a favorite diet of Orca whales and humans – are far more PCB-contaminated than elsewhere on the Pacific coast.

Although PCBs were banned by Congress in the 1970s, they persist in nature liked many other toxins. They can still cause cancer and interfere with the immune, development and reproduction systems of mammals – whether whales or humans. PCBs make whales more vulnerable to other illnesses. According to Canadian scientist Peter Ross, NOAA’s tests have established Puget Sound Orcas as “the most PCB-contaminated marine mammals in the world.”

“We need to pay attention to what’s going on to these guys because if we don’t, we’re going to have the same problems coming back and affecting us,” says NOAA scientist Brad Hanson. “These animals are eating wild fish we want to eat. Wild fish is good for us, too. But if there’s contaminants in it, it’s going to have an adverse impact on us.”

Background Essay Written by Hedrick Smith.

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