Scientist Connects Toxins To Increased Seal Mortality

This seal avoids the water's toxins by taking a leisure day.

(MARINE SCIENCE) NEW ENGLAND — Since September 1st, 128 dead seals have washed ashore the New England coast. These seal carcasses are some of the most contaminated in the world. Read on about the toxin tests needed to confirm the sea mammal’s already ‘sealed’ fate. — Global Animal
This seal avoids the water's toxins by taking a leisure day. Photo credit:, Charles McMahon

The number of dead seals washed up on the New England coast is not the only thing expanding, a spokeswoman from the National Oceanic and Atmospheric Administration said Tuesday. The area in which the seals are showing up is also increasing.

Maggie Mooney-Seus, a public affairs official for NOAA’s Northeast Region, said the number of dead seals found along the shoreline since Sept. 1 is now at 128. Last Friday, the figure was 94.

“The distribution of where they’re showing up is expanding,” she said.

Seals were first found on shores from northern Massachusetts to southern Maine. But Mooney-Seus said more seals are now being found in southern Massachusetts. All are considered to be “young of the year,” she said.

Mooney-Seus continued to emphasize the importance of leaving the carcasses alone. She said people should not approach or touch any marine animals, dead or alive. Disturbing a seal, or the carcass of a seal, is a federal violation and can lead to a hefty fine or jail time, she said.

In addition, people should try to keep their pets, namely dogs, away from seals and seal carcasses. Mooney-Seus said there is potential for a domestic animal to contract a virus from a seal.

“I encourage people to keep a safe distance,” she said.

The cause of the surge in seal deaths has not yet been named. Mooney-Seus said results won’t be known until test results on blood, tissue samples and the contents of the seals’ stomachs come back.

At least one expert said the cause of the seal deaths has less to do with pathogens in the animals and more to do with contaminants in the water.

Dr. Susan Shaw, director and senior scientist at The Marine Environmental Research Institute in Maine, has been investigating Gulf of Maine harbor seals and their exposure to toxic contaminants for almost two decades.

Shaw said her findings have shown that polychlorinated biphenyls, flame retardants, dioxins and other persistent pollutants found in seal tissue could be compromising their immune systems.

The problem, according to Shaw, is that tests to identify contaminants aren’t performed right away — and often not at all — because of the cost of conducting such tests.

“The role of contaminants as a factor should be at the front of the list,” she said. “But these studies take longer and can cost more.”

Having done her own tests on harbor seals over the years, Shaw said the ones found off the New England coast are the most contaminated in the world. Shaw is not involved in the current testing and said she compared her past results with testing done on the West Coast and in Europe.

“These seals are loaded with hundreds of toxic compounds,” Shaw said.

The contaminants are man-made and often find ways of seeping into the ground and into rivers and streams, eventually finding a way into the ocean, she said.

Shaw said there have been many “die-offs” over the years. She said they go unexplained often because the proper testing for contaminants is not done.

“I believe that contaminants need to have a role in these studies,” Shaw said.