A minke whale washed up on the Outer Banks last week, one of several dead whales found in the region in recent days.
Two humpback whales also washed ashore in Virginia Beach, and the first right whale calf born this year was found dead in Georgia. The calf had serious injuries to its head, mouth and lip, likely from a vessel strike.
Related: First North Atlantic right whale calf of the season spotted near the Carolina coast
A beached sperm whale stranded on a sandbar off Florida's Gulf Coast on Sunday and later died. Federal officials say at least 18 whales have washed up on East Coast beaches since Dec. 1.
North Carolina Museum of Natural Sciences Mammalogy Research Curator Dr. Michael Cove said that list also includes a dwarf sperm whale that washed up this week in the Outer Banks, and the number of whale deaths in such a short time is concerning.
"It does seem like a lot,” he said, “And it can be a little bit scary and depressing, frankly.”
With necropsy – or animal autopsy – results still pending, the cause of the deaths and strandings is not clear, but Cove worries that pollution in the Atlantic could be one factor.
"Some of this makes me wonder if we'll see evidence of things like the unfortunate consumption of plastics by these animals, and that is causing them to have blockages that that affect them,” he said.
In November, a live Gervais' Beaked Whale washed up in Emerald Isle and died soon after, and a necropsy found the female calf died from eating a plastic or mylar balloon.
He said the stranded whales in the past few weeks were of many different species – both toothed whales that eat things like squid, octopus, crustaceans and fish, and baleen whales that eat zooplankton and small fishes – and climate change is another factor that may have had a role in their demise, with rising water temperatures impacting the search for food.
"Some of our ocean temperatures are the hottest they've ever been,” Cove said, “And I have to wonder what that means for the food resources for some of these species, and if they're moving more because they're looking for food.”
Another risk to cetaceans is entanglements in fishing gear, but Cove said the modern commercial fishing industry is much more responsible – thanks, in part, to increased awareness – but there remains a lot of detritus in the sea.
"A lot of the flotsam out there, that's just old nets, old discarded nets that are floating around that are available for animals to get entangled in,” he said. “If they're plastic-based, they could be several decades old and have just been out there floating around and accumulating because those plastic nets don't breakdown.”
Whale conservation began in the 1970s and was needed because some species of whales like right whales were depleted -- extirpated -- nearly everywhere through commercial whaling in the 1800s. Others like sperm whales were depleted in many places, but apparently not all. Humpback and gray whales were heavily depleted, especially on their breeding and calving grounds.
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While any whale death is disquieting, Cove is most concerned for the future of the North Atlantic right whale.
"At least the minkes and the humpbacks are the lowest classification of endangerment, least concern, So, that's at least something to feel a little bit good about -- that their numbers have rebounded since historical whaling days and really, really detrimental declines back in commercial whaling days,” he said.
One of the difficulties of bringing the populations back up is that whales have long pregnancies, and long periods of time between them. "They hang out with mom for quite a while, and so the population growth rate is very slow as a consequence of that,” Cove said, “Because these whales have one calf and put so much energy into rearing that calf and it's really detrimental, especially in the case of the right whales, where their population is only in the few hundreds of individuals.”
Related: Dead sperm whale found near the point at Cape Lookout National Seashore
One method of reducing the harm to whales is to hold commercial ships to lower speed limits in areas the whales may be hanging out. On the East Coast, they are mandatory to protect the right whale. Data shows ships there comply 80% of the time. On the West Coast, where slowing down is voluntary, compliance is just 60%
But Cove said the speed limits work and, "We have seen kind of long-term benefits of these speed limits for vessels where there are fewer boat strikes than there historically were.”
Related: NOAA: stricter boat speed regulations being considered to save endangered whales
On the West Coast, a new system is called Whale Safe uses data from high-tech buoys, satellites and entries on a whale-watching app to predict the presence of whales in shipping lanes — warning the companies in near-real time so they can voluntarily slow down to 10 knots. Cove said with advances in technology, it’s a system that could make a difference in whale population recovery.
"Maybe using artificial intelligence to analyze that data in near real time so that it could continuously monitor and put out maps, almost like a heat map, of where whales are at any given point based on all of these different data streams,” he said. “From folks taking pictures with their cell phones, satellite tags, acoustic monitoring of the whale songs and other data streams. I'm sure there's plenty of other contributing data that I'm not even thinking of that probably exists.”
He also gave a warm shout-out to the organizations that give their time to the stranded and wounded creatures.
Related: Dead humpback whale found at Cape Lookout National Seashore
He said, "Marine mammal stranding teams that are responding to these animals, in many cases trying to save them while they're still alive and get them back out into the ocean, my hat goes off to them for their super responsiveness, their speedy reaction times, and all of the largely volunteer groups that help to do that.”
Not all of the whale news in the last week or two has been bad; though. A gray whale, whose species has been considered extinct in the Atlantic Ocean for 200 years, was recently spotted off the coast of Nantucket.
"It's always exciting when we hear about a species we thought was extinct is not extinct.” Cove said, “And that is part of why it takes so long for the fish and wildlife service or the IUCN or other institutions that are the groups that declare when a species is extinct is because these types of things happen.”
