Multiple fish that washed up dead in the Hudson River on the Nyack shoreline by Hook Mountain is causing concern.

Fishermen call the fish mossbunkers, but they are also known as menhaden fish. They say the fish washing up on shore dead is something that needs to be taken seriously.

Cliff Weathers, the spokesperson for Riverkeeper, says the fish could be dying of natural causes. However, he says nearby work on the Tappan Zee Bridge and the recent fire at Indian Point that led to an oil spill are matters that are being looked into.

The Department of Environmental Conservation is running tests on the fish to determine what killed them.