Roanoke Island What's New

NC Aquarium divers conduct lionfish mitigation study

A conservation team from the North Carolina Aquarium on Roanoke Island is working to manage population explosions in lionfish on shipwrecks off the coast of the Outer Banks. The lionfish is native to the Indian Ocean and South Pacific, but since the late 1980s the invasive species has been rapidly taking over reef and wreck sites along the East Coast.

The lionfish is a popular ornamental fish in home aquariums and was likely released intentionally into non-native parts of the Atlantic ocean, biologists say. Since they have no natural predator in the region, and eat almost any other aquatic species smaller than they, their populations have overcome reefs and wrecks, depleting natural fish populations and disrupting ecosystems.

“Shipwrecks on the Outer Banks provide habitats for all kinds of organisms important to the ocean’s food chain,” says NCARI Dive Safety Officer Shawn Harper “Which in turn are important to parts of commercial and sport fisheries, as well as other recreational users such as scuba divers.”

Harper says lionfish populations on wrecks have a negative impact on the juvenile fish populations who use those areas for food and refuge, especially during the warmer summer months, as well as smaller invertebrates such as crabs and shrimp who call these wrecks home year-round.

“Ultimately, these lionfish alter the local community,” he says. “By removing the lionfish, we aim to mitigate the negative impacts of their presence, and help preserve the native species.”

This summer, the NCARI dive team launched a project to determine if the lionfish population can be successfully controlled on selected wreck sites in the waters off the Outer Banks. The project is funded with a grant administered by the N.C. Aquariums Conservation Advisory Committee and provided by the N.C. Aquarium Society.

Over the course of several dives in August and September, divers took several excursions to three shipwrecks located as far out as 25 miles off the coast Hatteras Inlet.

“We first conducted counts of how many lionfish were within a known area of the wrecks,” Harper said. “Once we had an estimate of their density, we then harvested as many as we could. Next, we plan to revisit the wrecks and see if the lionfish populations returns to similar numbers.”

The team will also continue to remove lionfish on any dive it conducts.

“Even collecting one can make a difference in the long run,” he continues.

Lionfish are a relatively easy fish to collect by scuba divers using spears. Because they have no natural predators, lionfish typically display no fear when approached by divers. However, handling the fish is hazardous because of their famous venomous spines. To protect themselves, divers carry tube-shaped cases with one-way openings where they can deposit the fish directly from the spear’s tip without touching the fish.

The dives were all in the 90 to 130-foot range, so time on the wrecks was limited to around 20 minutes. To prepare for the outings, the NCARI dive team spent several dives conducting safety training from quarries in Wanchese on Roanoke Island and near Raleigh, as well as near-shore wrecks of Nags Head and deeper wrecks out of Oregon Inlet. During their spearfish training, they used foam footballs as stand-ins for lionfish.

“We were able to get comfortable with the equipment ahead of time, which was important considering the depth we were dealing with and the hazards posed by the lionfish,” Harper said.

Still, on the four dives where lionfish were encountered, the team was able to harvest 95 fish.

“There’s no good way to get each and every lionfish, so we’ll see when we return how much our efforts affected their numbers,” Harper said.

The lionfish mitigation project has another extra, possibly delicious, component. Lionfish are a tasty fish to eat. Once cleaned, including removing those pesky venomous spines, fillets can be prepared like any other fish with white meat. So a big part of this project is to introduce the lionfish as a delicacy to local diners by enlisting the help of Outer Banks seafood chefs, which is the focus of an upcoming Seafood Series program at the aquarium on November 14.

“We want to promote uses for these fish as we remove them from wrecks,” Harper says. “That includes trying out some recipes and even experimenting with lionfish fin jewelry, which is popular along the beaches in the tropics.”

The conservation dive team still has a few more dives to conduct before the first stage of the project is complete. A busy hurricane season forced them to postpone several dives, but they hope to get back out on the wrecks before winter sets in.

Check for updates on this project and more info about the Seafood Series at ncaquariums.com/roanoke-island.

Photo courtesy of John McCord with the UNC Coastal Studies Institute.

Posted by Brian Postelle at 9:00 AM

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