Researchers from Florida Atlantic University’s Harbor Branch Oceanographic Institute recently completed their survey of sharks and rays in Florida’s Indian River Lagoon.
The study, which was the first long-term, in-depth analysis of the elasmobranch community in the Indian River Lagoon from Sebastian to St. Lucie Inlet.
Indian River Lagoon is one of 28 estuaries designated as an “estuary of national significance” by the Environmental Protection Agency’s National Estuary Program. This site has been adversely affected by habitat degradation and harmful algal blooms that have resulted in degraded water quality and fish kills over the past decade.
“As global human populations increase and environmental pressures on estuaries become more widespread, it is essential to continue to monitor changes in elasmobranch communities in order to effectively manage and conserve these populations,” said Grace Roskar, M.S., lead author, current Knauss Fellow with NOAA Fisheries and former graduate student working with Matt Ajemian, Ph.D., co-author and an assistant research professor at FAU’s Harbor Branch. “Establishing updated records of the diversity and distribution of elasmobranchs in the Indian River Lagoon is a critical first step to understand how varying environmental and pollution impacts may affect these species, which are integral to the fish community of the lagoon and surrounding habitats.”
From 2016 to 2018, researchers caught 630 individuals of 16 species, including two critically endangered smalltooth sawfish (Pristis pectinata). They characterized the species composition and distribution of elasmobranchs, examined spatial and temporal variability in the elasmobranch community, and assessed how temperature, salinity, dissolved oxygen, depth, water clarity, distance to an inlet, and distance to a freshwater source affect elasmobranch community composition. The two most commonly caught species were bull sharks and Atlantic stingrays, the only two species to each comprise greater than 20 percent of the catch. The remaining 14 species comprised 53 percent of the catch.
Results of the study were published in Estuaries and Coasts, the journal of the Coastal and Estuarine Research Foundation.