PS 22-54 - Assessment of upside-down jellyfish populations (Genus Cassiopea) as potential bioindicators of human development in coastal ecosystems in Jobos Bay National Estuarine Research Reserve

Abstract: Bioindicators are used to detect environmental changes and provide quantifiable metrics of the health of ecosystems. Recent work with scyphozoans of the genus Cassiopea has revealed their potential as bioindicators in tropical coastal ecosystems, responding to disturbance of sediments and to pollutants. The ecosystems of Jobos Bay NERR (JBNERR) are under constant threat of degradation by anthropogenic activity, sea-level rise and associated hydrological changes. Because migration of these ecosystems is limited by coastal development, implementing effective management-action plans are essential. The focus of this project is to assess the potential of Cassiopea as bioindicators of nutrient pollution and other anthropogenic disturbances in coastal ecosystems. Research goals include to: (1) assess distributions of Cassiopea in the shallow subtidal zone adjacent to JBENRR; (2) determine substrate preferences that influence polyp settlement; and (3) develop and implement a long-term monitoring strategy for Cassiopea populations in coastal waters of Puerto Rico. Nine sites have been established in areas of Jobos Bay, three each as high, mild, and low human impact. Each site includes five transects within a 10 x 25 m plot. Videographic surveys are performed two ways: (1) a total recording of each transects and (2) recording 0.25 m² quadrats every 2 m along the 10 m transect for percentage coverage. Random quadrat tosses are also performed within the plot to compare methods to determine which method provides a better estimate of the population structure. Preliminary data show that Cassiopea populations respond to extreme climatic events such as the passing of Hurricane Fiona when populations migrated from near creek outlets to 3.2 km offshore. In addition, there was a significant decline in population density of Cassiopea (p < 0.05) after Hurricane Fiona’s passing, given drastic changes in salinity (S=20) and temperatures exceeding 24ºC in highly impacted areas. This project will further characterize these readily observed organisms as low-cost bioindicators to provide rapid environmental assessment to inform mitigation and restoration practices. We aim to promote communication and collaboration among local agencies, institutions, and organizations with the long-term goal of establishing the first jellyfish biomonitoring program in Puerto Rico and perhaps the Caribbean.