Hundreds of East Coast seals are showing up, stranded on New England shores dead or sick.

Harbor and gray seals on the northern Atlantic Coast of the United States have tested positive for avian influenza, or bird flu, according to the National Oceanic and Atmospheric Administration’s fisheries. Others have tested positive for phocine distemper virus, similar to the virus dogs can contract and which has caused epidemics among seals in other parts of the world, killing thousands, according to the National Institutes of Health.

Harbor seals

NOAA Fisheries

Both gray…