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Whale Coroners Probe Die-Off of Critically Endangered Marine Mammals

In recent weeks, nearly 2 percent of the imperiled North Atlantic right whale population has perished, while humpback whales continue to die in unusual numbers.

Written by Erica Cirino Published on Read time Approx. 4 minutes
Researchers examine one of the seven North Atlantic right whales that have died in the Gulf of Saint Lawrence in Canada since June.Marine Animal Response Society/The Canadian Press via AP

It’s dark, cold and dank, and the stale air of death surrounds me. Peering through the door of the steel freezer where I stand, I can see extra-long steel downdraft tables, bright overhead surgical lamps, sharp and shiny tools, floor drains and a fume hood. I’m in a morgue – not for people, but for deceased whales, porpoises and dolphins – at Woods Hole Oceanographic Institution’s Marine Mammal Center. Frost-covered creatures are hanging from hooks on the ceiling and are stacked on the floor waiting for the stories of their deaths to be revealed.

Showing me around is Michael Moore, a trained veterinarian and expert in marine mammal strandings and deaths. He explains to me in his British accent that the Center is responsible for investigating how and why these animals die. Currently, marine mammals are dying in unusually high numbers, notably endangered North Atlantic right whales in the Gulf of Saint Lawrence off Canada – where nearly 2 percent of the population has perished in recent weeks – and humpback whales off the Atlantic coast. Findings at Woods Hole and other marine mammal research centers suggest humans shoulder most of the blame for these deaths.

“We’re finding dead marine mammals covered with wounds from ship engines or tangled up in fishing gear,” said Moore. “Others we find have starved to death, because marine noise pollution or entanglement has reduced their ability to hunt, or they have been poisoned, succumbed to disease or simply lack food.”

According to Moore, entanglements with fishing gear pose the greatest threat to marine mammals, especially those with small, sensitive populations like the North Atlantic right whale. In fact, a full 83 percent of living North Atlantic right whales – a critically endangered species of which fewer than 500 individuals remain – bore scars of entanglement or were found wrapped in ropes in 2015, according to National Oceanographic and Atmospheric Administration (NOAA) scientists, who monitor marine mammal deaths off United States coastlines.

The Marine Animal Response Society, a Canadian nonprofit that responds to reports of injured, dead or disoriented marine mammals, has conducted necropsies on three of the eight North Atlantic right whales found dead in the Gulf of Saint Lawrence since June. The necropsies show that two whales suffered from injuries consistent with ship collisions, while a third was entangled in fishing gear. After an eighth right whale was discovered dead on July 19, Canadian officials closed the snow crab fishery in part of the gulf to prevent further entanglements.

Humpback whales feeding in the Great South Channel off Martha’s Vineyard in Massachusetts. (Erica Cirino)

In the recent humpback whale die-off, which NOAA scientists say first began in January 2016, 48 whales have been found washed up on the shores of 10 Atlantic states. Some of the whales have shown large gash-like injuries consistent with collisions with ship propellers. But scientists are reluctant to say that’s the sole cause of what they call an “unusual mortality event,” and instead remain open to the possibility that there is more than one factor involved in the deaths.

In one lethal event at Farewell Spit in New Zealand last February, more than 650 pilot whales beached themselves, leaving more than 400 dead. While people tried to save the whales by pushing them back into the water, many returned and washed up onshore. The cause of the stranding remains unknown. However, scientists at Massey University in New Zealand collected some of the whales for necropsies that may help them determine the cause of the stranding.

Marine mammals – especially whales – are very long-lived compared to many other ocean animals. When they die, they release large amounts of nutrients from their organs and flesh into the water, and their bones also create a habitat for other creatures. Historically, natural marine mammal deaths from old age or age-related disease would occur and help boost ecosystem health without harming marine mammal survival. Today, so many of these animals are dying there is concern for the future of their populations, according to Moore.

“There’s no doubt marine mammal deaths are on the rise,” says Mark Baumgartner, another marine mammal scientist at Woods Hole. “It’s critical we continue studying how and why they die to help prevent more deaths.”

The Marine Mammal Commission, an independent U.S. government agency created by the Marine Mammal Protection Act, is responsible for preventing human-caused marine mammal deaths. It oversees regulations governing the impact on marine mammals of fishing, noise pollution from seismic blasting and military activities and ship traffic. It also mandates research and environmental reviews when new, potentially harmful ocean activities are proposed. President Donald Trump’s proposed 2018 fiscal budget eliminates all funding for the commission.

“Human-caused marine mammal deaths are preventable,” said Baumgartner. “But we need rules in order for the deaths to be prevented – and we need enforcement so people follow them. And research drives rules – we need all of these things for the sake of these animals.”

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