Large predatory fish thrive on WWII shipwrecks off North Carolina coast
Grouper congregate across the conning tower. Credit: John McCord, UNC Coastal Studies Institute – Battle of the Atlantic expedition.

Während ein 2016 National Oceanic and Atmospheric Administration (NOAA) expedition to discover a pair of World War II shipwrecks that lie off the North Carolina coast, marine scientists ensconced inside glass-domed submersibles navigated to the Atlantic Ocean seafloor within the hope of profiling the fish communities residing on the wrecks. Some of the findings of this joint ecological-archaeological endeavor have been revealed this week within the Ecological Society of America’s journal Ecosphere. The two ships, a German U-boat and a Nicaraguan freighter, had not been seen by people since they sank almost 80 years in the past in the course of the Battle of the Atlantic. “These World War II shipwrecks are important historical monuments, but are also valuable habitat for fish,” stated Katrina Johnson, the paper’s first writer and a senior at Bates College in Lewiston, Maine.

Johnson, who grew up spending summers on a small Connecticut island solely accessible by boat, jumped on the alternative to hitch the analysis crew analyzing the info gathered in the course of the 2016 joint mission, despite the fact that she was not capable of take part within the mission herself. The expedition crew—led by the paper’s different coauthors—had fitted the manned submersibles with superior video and laser scanning gear, which elicited high-definition three-dimensional imagery requiring intensive processing and analyzing. The undertaking lent itself nicely to Johnson’s long-standing curiosity within the underwater world, and she or he, like the remainder of the crew, was shocked by the extent of fish life thriving on the wrecks.

According to Avery Paxton, Ph.D., a co-author on the examine and a analysis affiliate on the NOAA National Centers for Coastal Ocean Science (NCCOS) in Beaufort, N.C., the findings increase questions on how fish discover these distant websites within the first place. “Since the shipwrecks are such small islands of habitat on the sandy seafloor, it was surprising to see so many large-bodied groupers, like snowy and Warsaw grouper, occupying the shipwrecks,” Paxton stated. “This phenomenon warrants further study to determine how common this may be in other deep habitats.” The researchers used lasers to amass 3-D snapshots of fish to a millimeter stage of precision. For occasion, the detailed photographs allowed the crew to measure the scale of a grouper hovering beside the rivet of the U-boat’s hull or to doc the place of a wreckfish beside the barrel of the deck gun.

For fish neighborhood ecologists, these sorts of particulars are important. They can clarify why fish populations determine to name a shipwreck dwelling relatively than a rocky reef, for instance, and whether or not the hundreds of shipwrecks and different submerged human-made constructions scattered on the ocean flooring might function a major supply of fish habitat sooner or later. “Seeing so many large predators on such a relatively small habitat begs the question of how and whether they are feeding on these sites,” stated Chris Taylor, Ph.D., a analysis ecologist at NCCOS and a co-author of the examine. “We know some related species aggregate in very large numbers to spawn, and some species like Goliath grouper tend to aggregate on artificial habitats. But we don’t think that’s happening here.”

The success of the joint archaeological-ecological mission has opened the door to further collaborative ventures, which might doubtlessly be carried out by unmanned underwater automobiles sooner or later.

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Mehr Infos:
Katrina H. Johnson et al, Extracting ecological metrics from archeological surveys of shipwrecks utilizing submersible video and laser‐line scanning, Ökosphäre (2020). DOI: 10.1002/ecs2.3210

Ökologische Gesellschaft von Amerika

Large predatory fish thrive on WWII shipwrecks off North Carolina coast (2020, November 18)
abgerufen am 18. November 2020

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