A cargo ship and a carcarrier ship that were operating off Charleston are among nine commercial ships that have been charged with "egregious cases" of repeatedly violating a ship slowdown rule designed to protect rare right whales offshore on the East Coast.

But the ships represent only a fraction of the hundreds that come in and out of Charleston each year, among thousands in the East overall. By and large, ships appear to be complying with the rule.

Since the rule was implemented in 2008, one right whale death from a ship strike has been reported, a whale that stranded at Nags Head, N.C., said David Laist of the federal Marine Mammal Commission. A second dead whale was found in northern Maine, outside the slowdown zone.

At least two right whales were killed each year for four years before that.

Among them, the nine ships were issued a total of 56 violations in a period from 2009 to early 2011, according to reports released recently by the National Oceanic and Atmospheric Administration.

The MV Mol Endowment, a cargo ship, and the MV Courage, a carcarrier ship, were cited with seven violations off Charleston from mid-January to mid-April 2010, among 16 violations overall.

The violations each carry a $5,750 fine, but the amount can be appealed.

The right whale is the rare giant of the Atlantic, a 40-ton, 50-foot-long mammal that whalers nearly wiped out in the 19th century.

Only about 400 are known to exist today, so few that researchers consider each whale vital to the survival of the species.

The whales travel back and forth from their summer feeding grounds off New England to calve in the warmer winter waters off the Southeast coast.

Those waters are heavily trafficked, and ship strikes are considered a leading threat. 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 port interests fought the rule. The presence of the whales and rules to protect them were said to have disrupted everything from commercial shipping to naval warfare training. Shippers said the slowdown costs millions of dollars, and the whales are rarely struck.

Ship or propeller strikes aren't always fatal, and whales struck by a ship aren't always discovered. A collision with a ship can shatter whales' skulls, break bones and badly bruise, according to the Right Whale Listening Network website. Ship propellers can slice through skin and blubber or sever the tail.

Between 1970 and 2007, 24 of the 67 right whales that were found dead were struck, the website states.

According to the NOAA reports:

--Four violations by the Mol Endowment off Charleston were among seven by the ship overall in the winter of 2010. Two occurred off New York, and one was off Savannah. The ship is owned by a company based in Japan.

--Three violations by the Courage off Charleston were among nine by the ship overall in the winter of 2010. The others occurred off Brunswick, Ga. The ship is owned by a company based in the United States.

--The other seven ships were owned by companies with headquarters in Japan, Germany and the Netherlands.

An official with American Roll-On Roll-Off Carrier, part-owner of the Courage, did not return a phone call and email asking for comment.

Violators can face civil or criminal penalties. Violation notices are not issued to each ship found breaking the rule.

"We focus on the most egregious cases because our resources are limited. However, our enforcement is comprehensive as we cover the entire seasonal management areas," said Lesli Bales-Sherrod of NOAA.

"There's compliance to the law, which is black and white. Then there's commitment," said Jacob Levenson of International Fund for Animal Welfare.

The group studied compliance with the law in the Northeast. The study found that while ships don't always toe the slowdown line, most are slowing when they cross it.

"They intend to slow down, and that helps the whale," Levenson said.

NOAA tracks ship speed with land-based electronic monitoring, said an environmental group monitoring the enforcement; NOAA won't comment on enforcement methods. Right whale survey flights also collect ship speed data electronically and transmit it to the NOAA to be processed.

From November through Wednesday, a Sea to Shore Alliance survey flight team operating out of Charleston spotted 33 individual right whales in 27 flights, off a stretch of coast comprising most of South Carolina and northern Georgia. Last year at this time, 14 whales had been spotted in a similar number of flights.

No mother and calf pairs have been spotted so far, although a pregnant female spotted here later gave birth, said Dianna Schulte, flight team leader.

The flight team does not see the ship speed data. Schulte said her observations suggest that every now and then, a ship travels too fast, usually nearer to the outer edge of the zone, but "I think in general, they're doing very well."

Reach Bo Petersen at 937-5744.