More than 400 dead or stranded seals have washed up on the Maine coast so far this year, more than in any of the past seven years, according to National Oceanic and Atmospheric Administration (NOAA) statistics.
The immediate cause of the die-off is not yet known, but marine biologist Susan Shaw told the Portland Press Herald it could be related to toxic chemicals like polychlorinated biphenyl (PCB), which are found in high quantities in Maine harbor seals and make it harder for marine mammals to fight off disease.