The winter of 2017 has been grim for the scientists and volunteers who watch for endangered right whales off the Florida coast. Fewer whales have been seen than at any time since they started keeping track.

Only four adult right whales and three calves have been sighted offshore, scientists said this week. The winter migration season isn’t over, but chances are decreasing for any new sightings.

“It’s not looking good that the numbers will increase, either in terms of the numbers of individuals or calves,” said Jim Hain, program director for the Marineland Right Whale Project and a right whale scientist with Associated Scientists at Woods Hole. “This has all occurred despite relatively good weather and (aerial) survey conditions."

The low number of sightings come amid growing concern about critically endangered baleen whales along the North American coast.

Scientists have seen “a fairly dramatic decline in the distribution of right whales in other habitats such as their summer feeding grounds in the Bay of Fundy and the Great South Channel,” said Philip Hamilton, a research scientist at the Anderson Cabot Center for Ocean Life at the New England Aquarium.

A few reports have come from other locations, but not enough to account for all the ones that are missing, said Hamilton, who manages the North American Right Whale catalog. Off the Southeastern coast, scientists believe it’s the second lowest number of calves born in a winter season since they started tracking the whales.

“It’s disconcerting, to say the least,” said Hamilton. There’s concern “that the population as a whole has taken a turn and is in decline now.”

At one point, scientists were feeling better about the whales and their chances for survival. The National Oceanic and Atmospheric Administration passed new rules to help protect the whales from human-related mortality, including deadly commercial fishing gear and ship strikes. From a historic low of only about 50 whales after whaling was banned, the population had grown to more than 500 animals.

The whales were found off the coast of New England and Nova Scotia in the summer months. In the winters, pregnant females, accompanied by juvenile whales and some males, migrate to the waters off the Southeast Atlantic coast to give birth.

Over the winter of 2011, nearly 200 right whales were reported off the coastal waters off southeastern Georgia and northeastern Florida.

“As scientists, we used to think we had this figured out and everything was generally going in the right direction,” Hain said. “And then something changed and now everyone’s scratching their heads and trying to figure out what’s happening.”

Right whale scientists plan to gather at a meeting in Massachusetts in mid-March to address their widespread concern.

For years aerial survey teams and a network of shore-based volunteers have watched for whale sightings during the winter migration season, to help in the photo identification of the whales and to alert ships traveling in the area so they can avoid the whales.

Marineland’s Right Whale Project flies aerial surveys, as well as the Florida Fish and Wildlife Conservation Commission and the Georgia Department of Natural Resources. Marineland and the Brevard County-based Marine Resources Council coordinate the training and cooperation of volunteer whale watchers all along the Florida coast.

The most recent whale sighting off Florida was on Feb. 8, when a whale known as Tripelago was seen with her calf about nine miles east of Amelia Island. It was her fourth known calf.

A second whale, No. 1711, was seen with a calf, her third, off the coast of Georgia on Jan. 1, Hain said. They traveled south and were seen off New Smyrna Beach on Jan. 10.

A few days later, Julie Albert, coordinator of the whale sighting hotline for the Resources Council, photographed the pair off Satellite Beach. The next day the pair traveled into Sebastian Inlet for several hours.

Albert said she’s been hearing from volunteers who wonder where the whales are and why there aren’t any sightings.

Hain and others wondered if the whales were perhaps not migrating as far south, but the Georgia team has flown as far north as Cape Hatteras three times this winter and hasn’t seen any whales there either.

“It has been absolutely empty,” said Hain. Despite the fact there has been pretty reasonable survey weather, it’s just empty ocean.”

Calving dropped precipitously in the late 1990s, Hamilton said. In 1998, five calves were born. In 1999, 4 calves. Then, in 2000, only one calf was reported.

But even though there were few calves that year, Hamilton said 30 whales were spotted off Florida and Georgia, he said.

“We’ve never had all these things line up, the low number of calves, low number of individuals in the Southeast and the low number of individuals in the feeding habitat,” he said.

The only place seeing an increase in distribution is off Cape Cod, where they’re seeing more whales returning to a feeding habitat there.

Scientists have theories about what may be causing the declines.

Could it be the effects of climate change? The Right Whale Project monitors daily sea surface temperature reports and the water is warm, Hain said. Climate change may be a factor, he noted, but temperature events also are cyclical.

One of the most likely theories for the decline, Hamilton said, is that female right whales aren’t getting enough food.

“They have fairly long calving intervals, even when they’re healthy, delivering a calf only every 3 or 4 years,” he said. But while they’re pregnant and nursing, they lose up to a third of their body weight.

The evidence suggests that they may not be able to get enough food or that it may take much longer to restore their bodies enough to calve, Hamilton said, with whales calving only every 6 to 7 years.

Generally by this point of the calving season, around 90 percent of the calves have been seen.

There’s still a chance a mother-calf pair could show up offshore, and Hain encourages everyone, including mariners, fishermen and volunteers to continue scanning the ocean.

If and when a whale is sighted, Hain said, note the time and location, take photos if possible and call 888-979-4253 (888-97-WHALE).