It’s bad enough that the orcas of Puget Sound, off the coast of Seattle, are swimming in badly polluted waters. Now we’re learning they have a whole other challenge to deal with: air pollution.
The Seattle Times reports:
Killer whales – from Puget Sound’s endangered southern residents to the transient whales living hundreds of miles offshore – are inhaling bacteria, fungi and viruses once believed to be found only on land. Some of the pathogens are highly virulent. And some are even antibiotic-resistant.
The discovery comes as researchers also learn that respiratory ailments may be a leading cause of orca deaths, and that leads biologists to a new question:
Given that Puget Sound’s orcas are stressed and potentially more susceptible to illness, how much risk could exposure to new sources of infection pose?
“It’s pretty disturbing and opens a whole new can of worms,” said marine-mammal veterinarian Pete Schroeder. “We have an iconic species of animal that is in danger and whose ability to withstand a severe infection is in question. Now we know they can inhale antibiotic-resistant bacteria and it can live in their upper respiratory tract.”
Scientists study the effect of air pollution on the orcas by holding a long pole over their blowholes. The pole has petri dishes on it to collect the breath samples. It turns out that orcas are inhaling bacteria, fungi and viruses that were thought to be found only on land. Some of them are especially dangerous – and resistant to antibiotics.
Both the whale breath and the sea-surface samples contained bacteria that didn’t appear to belong there. Some bacteria did belong, but was antibiotic-resistant. There were strains of Salmonella and a rare bacteria known to cause pneumonia in humans. There was a pathogen responsible for gastroenteritis and gangrene, and a form of Staphylococcus resistant to penicillin. One pathogen normally found in marine waters was, surprisingly, resistant to six different antibiotics.
All of this simply adds to the water-borne pollution. Bacteria, chemicals and other organisms are constantly being washed into the ocean. Farm animal wastes flow into the rivers. Badly treated sewage seeps in. Boats dump sewage. Runoff from storm drains carries dog and other animal waste.
Plus the orcas’ immune systems are already compromised because of all the toxic chemicals, including DDT and PCBs that are still found in the fish they eat. And there are fewer and fewer Chinook salmon in Puget Sound – and the Southern Resident orcas only eat Chinook salmon.
Transient orcas – who spend most of their lives further out in the ocean and eat marine mammals rather than salmon – are also contaminated. A killer whale who had washed up dead in California was infected with a strain of Salmonella normally associated with birds, humans and livestock and that had never been seen before in a killer whale.
The Southern Resident orcas were deemed endangered by the federal government in November 2005 after years of legal action by conservationists.