URI grad student makes discovery about dragonfish

SOUTH KINGSTOWN – University of Rhode Island graduate student in marine biology, Ashley Marranzino, made a discovery about the sensory system of a group of deep sea fishes called dragonfishes.
Working with Biological Sciences Professor Jacqueline Webb, Marranzino researched the mechanosensory lateral line system of these dragonfishes, which detects water flows and low frequency vibrations in the water using tiny organs called neuromasts.
“I was interested in seeing how fishes in the deep sea are adapted to the lower light conditions of their environment,” said Marranzino, a Denver native who earned an undergraduate degree in biology from Regis University, in a statement. “If there is so little light, you would expect that the fish aren’t using much of their vision to guide their behaviors. Instead, maybe their lateral line system has evolved to become more sensitive.”
By examining specimens collected by former URI scientist Brad Seibel, using microCT imaging and scanning electron microscopy, Marranzino estimated that dragonfishes have more than 500 neuromasts on one side of their head and body.
There was only one previous study of the lateral line system of dragonfishes. Published in 1901, in German, this study estimated that these fish had 24 neuromasts.
“My findings highlight the fact that these fishes adapted to their environment by evolving and relying upon this non-visual sensory system,” Marranzino said.
Research on the lateral line system is helping develop small sensing devices to help self-directed underwater vehicles navigate and detect objects.
Marrazzino presented her research in June at the International Congress of Vertebrate Morphology in Washington, D.C.
In July, at the Joint Meeting of Ichthyologists and Herpetologists in New Orleans, she won the annual Frederick H. Stoye Award given by the American Society of Ichtyologists and Herpetologists for the best student presentation in genetics, development and morphology.

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