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Only about 450 Northern right whales are known to exist, according to the National Oceanic and Atmospheric Administration. File/New England Aquarium/AP

Any day now, walking the beach or in a boat offshore, you could come across something you might never again: a huge huff of breath and distinct double spout of air and water.

The rare right whales will begin arriving in South Carolina waters in the next few week to calve, at least researchers hope they will.

The whale is considered to be on the edge of extinction, with few remaining and no calves born last winter. The latest round of research might be its last line of hope.

On the heels of rules that slowed down commercial ships near the coast to prevent striking the whales, NOAA scientists have found that continuing to remove bottom-trap fishing lines could help more females survive.

The numbers are staggering:

  • 80 percent of all known deaths of female right whales (70 of 87) were caused by humans, either from getting tangled in fishing lines or struck by a ship. About half were from entanglements, based on a separate study.
  • 83 percent of all known whales have been tangled in fishing gear at least once in their lives, and the entanglements can last from months to years.
  • 59 percent have been tangled more than once.

The Northern right whale is a 60-foot-long, 40-ton giant mammal with fins as big as boats. By the last century, whalers had hunted them almost to extinction. Plentiful before the hunting, they are the now rarest of the large whales, with only abut 450 known to be alive, including only about 100 mature females.

Their recovery appeared to have turned a corner in recent years — a decade ago, 30 calves were spotted in a single year. But then four years of calving decline hit rock bottom last year, when no new calves were born.

The whales migrate seasonally between rich feeding waters off New England and warmer calving waters in the Southeast. Pregnant females make the 1,000-mile expedition so close to the coast that a mother and calf pair was spotted in 2005 in the breakers off Pawleys Island near Georgetown.

The proximity to fishing lines, boating and shipping has been deadly for them. 

The researchers found that struggling with fishing lines, among other hazards, has stressed the whales, and that females in a weakened body condition reproduced poorly. Getting them healthy could mean a 4 percent population growth per year, the study said.

"The body condition of North Atlantic right whales, as estimated using visual health assessments, has been declining over recent years, and periods of reduced calving success coincide with periods during which all individuals of the species showed poorer overall health," NOAA researcher and lead author Peter Corkeron said in the study.

The researchers recommended restricting the use of vertical trap lines — buoyed lines that hold traps on the ocean bottom. New acoustics technology is making it more feasible to find and collect "ropeless" traps without the buoys and lines.

"Any fishing trap with a line to the surface is a problem for the whales," Corkeron told The Post and Courier. "Even when the right whale numbers were increasing, they (the whales) could have done better and if they had we wouldn't find ourselves in a crisis now."

The whales do get tangled in their migration runs. In a well-publicized incident, biologists in 2011 were forced to use sedatives to calm a female enough to free her from 50 feet of line wrapped through her mouth and around her flippers off the border of Georgia and Florida.

The lines for bottom-placed black sea bass traps would appear to be the biggest threat in the Southeast. But the fishery was closed for a few years until 2017 to rework restrictions to better protect the whales.

Among other limits the federal South Atlantic Fishery Management Council has put in place are seasonal prohibited fishing areas, a reduction in the number of traps used and line modifications, said spokeswoman Kim Iverson.

Today, the pot lines generally are placed farther offshore than the 20-to-30-miles-out waters generally traveled by the whales, said Tom Swatzel, director of the South Carolina-based Council for Sustainable Fishing, which represents both commercial and recreational fishing interests. Longline fishing boats also tend to operate farther out.

From a commercial fishing standpoint, the council and NOAA have addressed the problem in the Southeast, he said.

Reach Bo Petersen Reporter at Facebook, @bopete on Twitter or 1-843-937-5744.

Science and environment reporter. Author of Washing Our Hands in the Clouds.