Gray whales continue to wash up dead and emaciated, but causes remain elusive
With a massive and unpredictable killer whale population in their midst, the world’s oceans may be in for a new bout of marine mammal extinction.
Recent evidence suggests that the rate of marine mammal die-offs has increased over the past decade and that the largest population in history is dying at a furious pace.
The National Oceanic and Atmospheric Administration (NOAA) reports that there have been more than 20,000 carcasses found in the waters around Hawaii since 2005, the majority of which are black and white striped orcas.
While scientists have long suspected that the mass extinction of cetaceans was occurring, it remains a mystery as to what has been killing these whales, or why they are dying.
The culprits are still being sought.
“What we can’t know right now is what’s killing them,” said marine biologist Dr. Amy Vickers of NOAA’s National Marine Fisheries Service-University of Hawaii’s Marine Mammal Institute.
“For us to be able to say what’s killing them or what’s making them sick, we need to do more research on them.”
NOAA has made a commitment to continue investigating the causes of the extinction.
As part of its ongoing research, scientists have been sampling the stomach content of more than 120 California sea lions and found that 90 per cent of them had some stomach-turning symptoms, including bleeding, ulcers, bleeding disorders and stomach ulcers.
Researchers also found that the stomach contents of many whales and dolphins are riddled with stomach conditions such as bacteria, viruses and parasites.
The symptoms of illnesses in dolphins and whales have a similar pattern, but scientists are not yet sure what diseases drive them.
NOAA is also on the case.
Agency spokesman Tom Simon said the agency was “working closely with NOAA’s Marine Mammal Institute to investigate other suspected causes of whale mortality.”
The institute is based at the University of Hawaii’s Marine Science Institute.
“We’re trying to find exactly what the health conditions are in the ocean and also what’s causing them,” Simon said.
Dr. John Topp, the director of the Marine Mammal Institute, said he was concerned about what he thought was a declining population of marine mammals, but he was unsure of the source of the population decline.