When Chris Taylor presses play, footage of blue wrasse and greater amberjack fills the screen. The fish whirl and spin against a vivid backdrop of corals, sponges, and algae. When Taylor, an ecologist at NOAA’s National Centers for Coastal Ocean Science in Beaufort, North Carolina, asks visitors to the Centers where they think the video was taken, he’s not surprised to hear the Florida Keys or the Caribbean. But the guesses are invariably wrong.
“These highly structured reefs are right off our coast,” Taylor says. “There are all of these brightly colored fishes that defy expectations.”
A new study in Nature Communications Biology by Taylor and Avery Paxton, a marine ecologist who divides her time between NOAA and the Duke University Marine Laboratory, shows artificial deepwater reefs off the coast of North Carolina increased the number of tropical and subtropical fishes at the northern edge of their ranges. These findings have important implications for fishes in warming waters. As ocean temperatures rise, artificial reefs may facilitate the movement of these species towards the poles, where they may be able to find habitat that is more suitable in the future.
“It matches up with what we’ve seen anecdotally, so it’s nice to see a formal study of this,” says Robert Martore, a marine biologist with the South Carolina Department of Natural Resources.
Accidental (and recreational) reefs
Rocky reefs like the ones that occur naturally off the coast of North Carolina function much like their coral reef cousins. But unlike tropical reefs, which have an underlying structure built by living coral, the skeleton of temperate reefs is made of rock or other non-living substrates. Said rock can take many forms. It can be as flat as a parking lot or a seafloor strewn with boulders. Still other temperate reefs form in the cliffs and ledges of the continental shelf.
Supplementing these natural reefs are artificial reefs, that range from shipwrecks to deliberately placed human structures such as concrete pipes, bridge trusses, and decommissioned tugboats, says Martore, who also runs the state’s artificial reef program.