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.
It comes as figures reveal 2017 as a ‘devastating year’ for dolphins and porpoises, with a total of 249 cetaceans recorded as Marine Strandings along the Cornish coastline – the highest recorded since 2003.
About 12 of the 2017 cases were found in Monterey County sea lions, the Monterey Herald reported. Leptospirosis is caused by a spiral-shaped bacteria called leptospira. Two of the cases were in Santa Cruz County.
“We documented for first time marked changes in the pelagic food web length in response to various natural and anthropogenic related stressors,” said lead author Rocio I. Ruiz-Cooley, formerly of NOAA Fisheries’ Southwest Fisheries Science Center and now at Moss Landing Marine Laboratories. “This tells us that the food web is very dynamic, and reveals changes with the ecosystem around it.”
Researchers at Ano Nuevo found the mercury level in the water during the molting season 17 times higher than what it is at other times of the year. That led them to look at where the mercury was coming from: the seals themselves. The molted skin takes with it some of the mercury that the seals have accumulated from the prey they eat in the ocean. Their blood and muscles have higher concentrations of mercury than would damage the nervous system of a human.
“What I saw next really surprised me. There was indeed a dead otter on the beach but there was another otter touching it with its nose and paws almost as if it was trying to revive the deceased otter. This continued for several minutes.”