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Researchers examine how smell attracts fish to reefs

Courtesy of NOAA


Fish can tell by the way a coral reef smells whether or not it’s the perfect home for them, and University of Delaware researchers want to learn more about how that works.

UD marine scientist Danielle Dixson said some reefs emit chemical cues like odors or carbon dioxide, which can make them seem more or less attractive to fish. 


Now, with a new $1 million grant from the Gordon and Betty Moore Foundation, Dixson will delve into the chemical composition behind this phenomenon, manipulating lesser populated reefs with chemical cues to see if they can draw fish in.


“We can call the larvae into those habitats that aren’t getting recruitment happening,” Dixson said, “and then potentially that could be another really effective management strategy that could be used in coral reef protection.”


Fish need a reef for a home and protection, but they can also help protect it. By eating surrounding algae, they lower any negative effects algae could have on corals’ health. Conservation management approaches for reefs are needed because coral reefs are threatened by unsustainable fishing, climate change and agricultural runoff, among other things, according to the National Oceanic and Atmospheric Administration.


NOAA also said reefs are “one of the most valuable ecosystems on Earth” because of their coastal protection and food they provide to fish. They recently banned sharp bottom fishing gear in a part of the Atlantic Ocean, including 66 miles off Delaware’s coast because of the damage some gear can do to brittle coral. 


One crucial detail Dixson feels is overlooked when fish choose a coral reef, is whether the fish arrive at the reef during the day or at night.


“If it happens at night and in the morning you wake up and you count how many recruits you find, the issue with that is you don’t know how many animals came to the reef and decided not to settle or got eaten in the time that you came in and the time that you were able to count them,” Dixson said.


Dixson published research in 2014 that concluded the chemical cues emitted from a habitat can help marine animals decide whether or not they want to live there.


Other collaborators on this project include Valerie Paul, a scientist at the Smithsonian Marine Station, Tony MacDonald, the director of the Urban Coast Institute at Monmouth University, West Long Branch, NJ and Jay Odell, the Mid-Atlantic marine program director at The Nature Conservancy.


Researchers will start collecting data from Belize over the summer and will analyze it over the next three years.

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