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Session 5, Abstract 25

NUTRIENT VALUE OF INVASIVE SEAGRASS, ​HALOPHILA STIPULACEA​, AND ANALYSIS OF ITS ABILITY TO MEET THE DIETARY NEEDS OF GREEN SEA TURTLES IN THE CARIBBEAN

Candice Cross* (Demian A. Willette), Loyola Marymount University, Department of Biology, 1 LMU Drive, Los Angeles 90045

Seagrass habitats serve as one of the most valuable marine ecosystems and provide shelter, nursery, and food to a diverse range of tropical marine animals. Within the Caribbean, Thalassia testudinum, commonly known as “turtle grass,” comprises the majority of green sea turtle diet along with other native seagrass species, Syringodium filiforme and Halodule wrightii. Surveys from 2002 to 2017 report the increasing expansion of invasive seagrass, Halophila stipulacea, in addition to its ability to outcompete and replace native beds along the shorelines of various Caribbean islands. The abundance of H. stipulacea in comparison to native species has caused an inevitable shift in the dietary pattern of green sea turtles. The study focuses on H. stipulacea’s ability to satisfy the nutritional requirements of the green sea turtle and the corresponding impact the invasive grass will have on growth and development. Samples of H. stipulacea, T. testudinum, S. filiforme, and H. wrightii were collected from waters around St. John, one of the U.S. Virgin Islands, for comparative dry matter, ash, and phenol analysis. Though each species fills a unique ecological niche, Halophila shows significantly lower levels of carbon, nitrogen, and proteins. Moreover, the invasive’s high epiphyte content, compared to native seagrasses, may act as a deterrent for feeding turtles. Collaboration with National Park Service in monitoring the effects of the invasive species and its trophic disruption will offer more insight into the necessary protocol regarding seagrass biodiversity conservation.