The mammoths of the Atlantic are back on the move — right whales headed south to calve. The huge, rare, imperiled animals will soon be swimming off the Lowcountry coast.

This year, though, you’re not likely to know when. For the first time in years, no survey crews will fly from here. The only time commercial ships will be alerted to watch is if somebody happens across one or more of the whales and reports it.

That alarms conservationists who have fought to protect the few remaining whales of what is considered the most endangered marine mammal species in the world.

“There’s no question that this species is still on the brink of extinction,” said Charles “Stormy” Mayo, Provincetown Center for Coastal Studies senior scientist. The whales’ two biggest manmade threats are ship strikes and line entanglements.

The survey flights gave “a real time reflection of the position of the whales, and whether they were injured or in trouble. It’s basic biology as well as direct management and protection of the species,” he said. Without the flights “they are at substantial risk.”

Last year, 18 individual whales including five mother-and-calf pairs were spotted off South Carolina.

The flights were suspended because of the loss of private funding and cuts in federal funding. They still will be flown over Georgia and Florida, the heart of the winter calving grounds.

As the flights end off South Carolina, the National Oceanic and Atmospheric Administration is poised to continue leasing the East Coast offshore waters for Navy training and testing that includes explosives and loud sonar known to harm whales, that communicate and navigate by echolocation.

And the fought-over ship slow-down rules are under review.

“Both of those work very much against the whales,” Mayo said.

The coastal waters are heavily trafficked. The presence of the whales and rules to protect them are disrupting everything from commercial shipping to naval warfare training.

Partly because of the aerial survey work, NOAA in 2008 mandated that large ships within 23 miles of the coast must slow to half-speed when the whales are around. Shipping and ports interests fought the rule. Observers say it is sometimes violated by both military and commercial vessels.

Shipping interests have maintained that whales were not often struck before the rule, and no whale has ever been reported struck in the Charleston shipping channel.

NOAA scientists say that, while few whales were struck before the rules were put in place in 2008, no whales have been struck since in the slow-down range.

Right whales are the rarest of the large whales, 40-ton creatures hunted close to extinction a century ago. Today fewer than 500 are known to exist in the north Atlantic Ocean, a slight improvement from a low of few more than 300. But with so few animals remaining, every whale is considered vital to the survival of the species.

“Even with the ship speed rule in place I always have concerns about right whale interactions with ships,” said Cynthia Taylor, of Sea to Shore Alliance, the group that flew the surveys. “I remain optimistic that the ship speed rule will be extended. Aerial surveys do help with the mitigation of ship strikes, but because we only fly during daylight hours on good weather days, it is a limited system and not the ultimate solution to the problem.”

Reach Bo Petersen at 937-5744, @bopete on twitter or Bo Petersen Reporting on Facebook.