Marine Mammals

Why Are Gray Whales Dying Off?

Some scientists believe there may be too many whales for the population to sustain itself. Others say this explanation of “overcapacity” and “natural causes” overlooks the gantlet of hazards that grays now face — including ecosystem alteration, ship strikes, entanglement in fishing gear, plastics pollution, disease, ocean acidification and loss of kelp forests.

Mass Die-Offs Continue to Threaten Marine Life

Balmy temperatures can lead to conditions perfect for the spread of infectious diseases, Sanderson said. When sea ice melts too early in the season, seal pups must enter the water before they are ready to be weaned, leaving them weaker and more vulnerable to disease. Vanishing sea ice also means that seals and sea lions in cold regions will have less space to emerge from the water to rest, breed, or escape predators, forcing them to crowd more tightly together.

Lerptospirosis Outbreak among Calif Sea Lions

The center said it sees a surge in the number of sea lions admitted with symptoms of leptospirosis every four to five years. Before the 2017 outbreak, the most recent ones occurred in 2011 and 2008. During the 2011 outbreak, about 200 sea lions infected with leptospirosis were admitted to the center, according to a news release.

Less than 500 North Atlantic Right Whales Remain

Last year saw an alarming dieoff of North Atlantic right whales, something researchers refer as an “unusual mortality event.” Their carcasses littered the shores of the east coast—12 in Canada and 5 in the United States. Necropsies revealed that most of the animals died from blunt force trauma or entanglement issues. This brings the North Atlantic right whale’s fragile population to an estimated fewer than 500.