Animal carcasses floating down the St. Lawrence is a grisly but familiar sight and one group is asking witnesses to report such morbid aquatic observations.

Every year hundreds of expired animals, such as seals, turtles and whales float down the river and the Emergency Response Network for Marine Mammals want people to help then learn how and why they perished.

Many aquatic beasts are claimed by unfortunate contact with boat propellers, so those who have seen such incidents are asked to call and advise the group at 1-877-863-5884.

Some animals, such as beluga whales, are closely monitored by Fisheries and Oceans Canada. Those carcasses are often sent for dissection at a lab to test for toxins. Some deteriorated corpses are given cursory tests on site.

The network of Marine Mammals has hundreds of volunteers and welcomes others to join in their efforts.

-With a file from The Canadian Press