In the past six weeks, five federally protected marine animals have been killed at Savannah Harbor as work crews dredge the shipping channel to maintain and deepen Georgia’s biggest port.
A green sea turtle, two Atlantic sturgeon and a loggerhead sea turtle have died during dredging work since Jan. 1, while a leatherback sea turtle was killed under unknown circumstances, say officials with the National Marine Fisheries Service.
At this point, federal agencies aren’t overly concerned about the deaths because they say some animals — even rare ones — are expected to be killed during dredging projects, such as the $706 million port deepening underway this winter.
But if too many federally protected species die as a result of dredging, it could affect how port deepening and maintenance are conducted in the future.
Should it become apparent the U.S. Army Corps of Engineers will exceed the number of animals legally allowed to be killed during dredging, the fisheries service could require tighter controls on the dredging operations at Savannah, the fisheries service said last week.
That could range from a different dredging schedule to a temporary shut down of the work so officials can seek better ways to protect endangered species. Such measures likely would occur in extreme circumstances, federal officials said.
“If they had more takes than we anticipated, we would have a conversation, basically, on why we think that was happening,’’ said David Bernhart, a marine fisheries service protected resources administrator. “Are there any additional measures that would avoid this?’’
Savannah, like Charleston, is racing to deepen its harbor to accommodate larger ships.
The Corps’ port dredging project in Savannah finally began in the fall after more than 15 years of battles over the environmental impact the work would have on the harbor and on the Savannah River. The dredging will deepen the shipping channel from 42 to 47 feet. Charleston has had issues, as well, although dredging there has not produced the bitter fights that preceded the launch of the Savannah project.
Having a deeper channel for bigger ships is expected to keep both ports competitive — but the Savannah and Charleston dredging projects have an array of environmental rules that must be followed, including protection for endangered or threatened species such as sea turtles, fish and whales.
That includes limits on the number of animals that can be killed.
The Savannah port deepening work, for instance, allows dredges to “take,’’ or kill no more than four Atlantic sturgeon during the harbor deepening project over three winters. That leaves room to kill only two more Atlantic sturgeon during the dredging project over its three-winter schedule. The two sturgeon that died Jan. 26 were discovered by an independent contractor assigned to the dredge, according to the Corps of Engineers.
Atlantic sturgeon are among the most recent additions to the federal Endangered Species Act list. In 2012, the federal government declared Atlantic sturgeon as endangered and in need of protection because populations are declining. A large, prehistoric-looking fish covered in bony plates, the Atlantic sturgeon can grow to 16 feet. Their numbers have dwindled because of overfishing and habitat loss.
Dredges in Savannah also aren’t allowed to kill more than three green sea turtles while the work continues over three winters. That leaves only two more green turtles that can be killed during the harbor deepening work.
Green sea turtles are large reptiles that can grow to 4 feet long and weigh up to 440 pounds, according to the U.S. Fish and Wildlife Service. The federal government listed them under the Endangered Species Act in 1978 as the loss of nesting habitat, entanglement in fishing nets and other factors took their toll on the sea reptiles. Their populations have rebounded in recent years and federal officials are considering loosening some restrictions. Still, green sea turtles remain protected and are not common in Georgia or South Carolina during the winter.
The marine fisheries service “is always concerned about the loss of (endangered or threatened) species, but we recognize that sometimes losses are unavoidable due to the type of action being performed,’’ service spokeswoman Kim Amendola said, noting that “the use of hopper dredges as a part of the Savannah Harbor deepening is essential to completing the work safely in a reasonable time frame.’’
Jaclyn Lopez, an endangered species lawyer with the Center for Biological Diversity, called the deaths of five rare animals in six weeks “alarming.’’ While the fisheries service doesn’t think the deaths will hurt overall efforts to replenish turtle and sturgeon populations, Lopez said the loss of a single animal shouldn’t be ignored.
“It does seem alarming that you would lose five of these individuals,’’ Lopez said. “We are not talking about pigeons. We are talking about animals that in some cases are very rare and in other cases have been placed on the precipice of extinction because of different combined factors that have mostly humans behind them.’’
When animals are protected under the Endangered Species Act, specific plans often are developed to help species recover from years of population declines.
Corps officials in both Savannah and Charleston said they are committed to following rules to protect rare animals and fish. Sometimes, for instance, that involves measures to frighten sea turtles so they will move out of the path of dredges, said Savannah Corps spokesman Billy Birdwell.
“We can’t see the bottom of the ocean out there,’’ Birdwell said, noting that the Corps doesn’t have cameras to look for turtles in the murky water. But he said “We do what we can to basically scare the turtles away. Sometimes we’ll drag something along in front of the dredge that moves them out of the way, that stirs them up or wakes them up.’’
Glenn Jeffries, a spokeswoman for the Corps in Charleston, said her agency will follow a plan to protect sea turtles when dredging starts at the South Carolina port, a major competitor to Savannah for business. That $521 million project is expected to begin in about two years. Channels would be deepened from 45 to 52 feet.
Fisheries service officials said the green sea turtle and the two sturgeon may have died because they were near the bottom of the harbor and in the path of hopper dredges, considered more dangerous to some marine life than other types of dredges.
As opposed to some dredges, a hopper sucks material from the bottom with the use of machinery that is dragged across the harbor floor, according to the Corps. But the dredges move faster than some marine life that lie in their path — and that can be lethal. From 2000 to 2010, for instance, hopper dredges killed 10 sea turtles in Savannah Harbor’s navigational channel.
As a result, hopper dredging is to occur only from mid-December through March, when sea turtles are less likely to be in the area, the Corps says. Hopper dredging has been in the harbor’s outer channel this winter, the Marine Fisheries Service says.
Still, it’s not common for hopper dredges, the preferred machinery used by Corps contractors, to kill either green sea turtles or sturgeon.
The juvenile green turtle that died Jan. 5 in Savannah is only the second known green sea turtle to have been killed during a dredging operation in the history of the Georgia port, Bernhart said. One was killed four years ago during a maintenance dredging job, records show.
Loggerheads and leatherbacks
In addition to the green sea turtle and two sturgeon that died from the harbor deepening project, a maintenance dredge killed a loggerhead sea turtle Jan. 1, according to the marine fisheries service.
Loggerhead sea turtles, which can grow to three feet long and weigh 250 pounds, are more common on the Georgia and South Carolina coasts than green sea turtles. Loggerheads were listed as threatened in 1978 under the Endangered Species Act. The maintenance dredging operation that killed the loggerhead is not connected to the dredging to deepen the harbor.
Federal officials say they do not think the recent death of a leatherback sea turtle, reported Jan. 11, was related to dredging because the animals are not typically found near the bottom of harbors and in the path of dredges. Officials are unsure what killed the sea turtle, but say it may have been a ship strike. Leatherbacks are the largest of sea turtles, growing to up to 6 feet and weighing as much as a ton. They are known to migrate great distances. They are listed as endangered under the law.
But federal officials think warmer weather is why some sea turtles, particularly cold-intolerant green sea turtles, lingered in the area longer than they normally would have. Water temperatures along the coast remained in the 60s through much of December and early January, according to federal and state data.
On New Year’s Day, for instance, the water temperature reached 67 degrees in Charleston Harbor, according to the S.C. Department of Natural Resources.
With cooler weather recently, water temperatures along the South Carolina-Georgia coast have dropped into the upper 40s and low 50s. That gives hope that green sea turtles have moved back toward Florida while this winter’s dredging continues, state and federal officials said.