{"id":15454,"date":"2021-09-20T11:14:07","date_gmt":"2021-09-20T15:14:07","guid":{"rendered":"https:\/\/ncseagrant.ncsu.edu\/coastwatch\/?page_id=15454"},"modified":"2024-08-19T12:13:59","modified_gmt":"2024-08-19T16:13:59","slug":"currents-fall-2021","status":"publish","type":"post","link":"https:\/\/ncseagrant.ncsu.edu\/coastwatch\/currents-fall-2021\/","title":{"rendered":"Currents: Invasion on the Mudflats"},"content":{"rendered":"\n\n\n\n\n

Aaron Ramus received the 2020 Coastal Research Fellowship, which North Carolina Sea Grant and the N.C. Coastal Reserve and National Estuarine Research Reserve Program sponsor jointly. Ramus, a Ph.D. candidate at the University of North Carolina Wilmington, studies the ecological impacts of “Gracilaria” in estuaries in the Southeast. He received his master\u2019s in marine biolog y from UNC Wilmington and his bachelor\u2019s in biology from the University of North Carolina at Chapel Hill.<\/em><\/p>\n\n\n\n

Intertidal mudflats, shallow muddy areas exposed during low tide, are actually quite common in North Carolina\u2019s estuaries. Although they might not seem as scenic or picturesque as other coastal habitats, these mudflats are home to myriad invertebrates \u2014 species without a backbone \u2014 as well as to fish and seabird populations.<\/p>\n\n\n\n

These mudflats also support numerous fisheries, including the hard clam Mercenaria mercenaria<\/em>. Hard clams are edible, filter-feeding bivalves that constitute the basis for a popular recreational and major commercial shellfishery in North Carolina that generates more than $3.7 million annually, according to the N.C. Division of Marine Fisheries.<\/p>\n\n\n\n

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Does the presence of Gracilaria affect the production of hard clams, like these on the Masonboro Sound? Credit: Aaron Ramus.<\/figcaption><\/figure>\n\n\n\n

However, many of North Carolina\u2019s mudflats are now also home to a new species \u2014 a black, stringy, disheveled-looking seaweed known as Gracilaria vermiculophylla<\/em>. In fact, nonnative Gracilaria<\/em> has recently invaded almost every estuary in the southeastern United States, from Georgia to Maryland, and it appears Gracilaria<\/em> is here to stay.<\/p>\n\n\n\n

When Gracilaria<\/em> invades, it forms complex micro-habitats in these intertidal areas that previously were largely devoid of vegetated structure. Because predators \u2014 such as whelks, seabirds, stingrays, and blue crabs \u2014 play a major role in controlling populations of benthic (bottom-dwelling) invertebrates on intertidal mudflats, Gracilaria<\/em> could provide benthic prey with a refuge from predators. This could potentially modify predator-prey interactions on invaded mudflats, with important implications for the production of hard clams in North Carolina estuaries.<\/p>\n\n\n\n

Many invasive species have negative impacts on the functioning and health of ecosystems and pose serious challenges for managers. In particular, it\u2019s often unclear exactly where invasive species occur, and, even when we do know, we frequently don\u2019t understand the invader\u2019s impacts adequately.<\/p>\n\n\n\n

Watch a video about Aaron Ramus\u2019s research on non-native Gracilaria:<\/em><\/strong><\/p>\n\n\n\n

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