Sea turtle expert concerned by proposed year-round dredging at state ports

Dr. Craig Harms handles a sea turtle under the care of the N.C. Aquariums in this undated photo. (Contributed photo)

MOREHEAD CITY — A local sea turtle expert said last week he’s concerned about a U.S. Army Corps of Engineers proposal that the state eliminate the “window” in which channel maintenance by hopper dredge is allowed at the ports of Morehead City and Wilmington.

The federal agency says the move would increase the availability of dredge boats and ensure the work can occur year-round, on a timely basis. The proposal would remove the Dec. 1 to April 15 environmental dredging window.

“Eliminating the seasonal restrictions on dredging and increasing the lethal take limits …would not be well-aligned” with the longstanding U.S. policy to protect threatened and endangered sea turtles, Dr. Craig Harms, a doctor of veterinary medicine at N.C. State University College of Veterinary Medicine and the N.C. State Center for Marine Sciences and Technology in Morehead City, said in an email last week.

A hopper dredge is like a vacuum cleaner, it sucks up the material and transports it elsewhere for discharge, resulting at times in what officials call “lethal takes,” which is when a sea turtle or other wildlife is sucked up and killed in the process.

Dr. Harms, who works with injured and sick sea turtles for N.C. Aquariums, is the lead author of a peer-reviewed and recently published scientific paper on the subject.

“I am definitively not opposed to dredging, and I don't want this paper to be interpreted as such,” Dr. Harms said. “Shipping channel maintenance and beach construction are vital to the economic health for both coastal and inland communities.

“But this is a cost that shouldn't be glossed over. ‘Lethal take’ is an antiseptic euphemism for running a live sea turtle through a wood-chipper, and there are ways to minimize the number of turtles making that trip.”

Further, he said in the email, “Turtles caught in hopper dredges used in shipping channel maintenance or beach construction projects usually die from massive blunt force trauma and dismemberment.

“The rare survivors can suffer from an additional complication – gas bubble formation in blood vessels from decompression. Continued survival is unlikely without treatment and rehabilitation,” he continued.

In its draft environmental assessment for year-round dredging at the ports, the ACE states, “Maintenance dredging of existing channels will result in minor and short-term impacts to water quality, noise, benthic (bottom-dwelling) organisms, important fisheries and protected marine reptiles and mammals and critical habitat.”

However, it adds, “Hopper dredge availability is limited, making it very challenging to adequately maintain the (Wilmington) District’s two deep-draft navigation projects, Wilmington Harbor and Morehead City Harbor, within the existing environmental window.”

In a letter to the ACE this fall, Daniel Govoni, federal consistency coordinator for the N.C. Division of Coastal Management, said the Department of Environmental Quality, his division’s parent agency, believes the proposed change is “consistent to the maximum extent practicable” with state environmental policies.

However, Mr. Govoni also requested that if the change takes place, the ACE make efforts to reduce potential impacts to aquatic species.

The state took comments on the proposal in October and November, but has not announced a decision or the timetable for one.

Dr. Harms, in an interview Monday, said he sent his comments to the DCM before the Nov. 25 deadline and knows of other turtle experts who are equally concerned and submitted comments in regard to allowing dredging year-round and increasing the number of lethal takes.

“One of the arguments made (by the ACE) is that during winter months sea turtles are lethargic and therefore less able to evade dredge activity, and that when they are warmer and more active, they will be more able to avoid dredges,” he said. “That seems biologically quite plausible and worth evaluating, but dredging in Virginia this past spring through fall indicates the opposite. When more turtles are present during dredging, more encounters occur.”

In addition, he said in the email, “Although the large majority of sea turtles sucked through hopper dredges do not make it through alive, or even in one piece, the few survivors require substantial care to stay alive and to be released.

“Although I recall several years ago dredging operations taking financial responsibility for that care, that has not happened in recent years, and no mention is made in the 2020 SARBO (South Atlantic Regional Biological Opinion) for assuming any such responsibility in the future.”

To view the 2020 SARBO, visit file:///C:/Users/12528/AppData/Local/Temp/SARBO_Acoustic%20Revision%206-2020-Opinion_Final.pdf.


Contact Brad Rich at 252-864-1532; email; or follow on Twitter @brichccnt.

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