Indian River (Fla. : Lagoon)

The objective of this research was to examine bottlenose dolphin (Tursiops truncatus) habitat use in the Indian River Lagoon (IRL) based on monthly relocation of photo-identified individuals, prey availability and environmental factors from 2003-2015. We focused on the variation of spatial and temporal abiotic and biotic factors and their influence on bottlenose dolphin habitat use patterns. Harbor Branch Oceanographic Institute (HBOI) conducted monthly photo-identification surveys along the length of the IRL and GPS locations of photographed dolphins were collected at the time of surveying. Stratified random samples of prey and environmental variables were collected monthly by the Florida Fish and Wildlife Conservation Commission (FWC) as part of the Fisheries-Independent Monitoring (FIM) program. Kernel density estimation was used to determine the magnitude-per-unit area of dolphins across a continuous raster surface of the IRL by wet and dry seasons each year, the values of which were used as a response variable in Classification and regression tree (CART) analyses with FIM fish community and environmental factors as predictors. Understanding how dolphins respond to environmental factors over time in the IRL could be used to predict future responses in estuaries and prioritize conservation and restoration actions.

In the eutrophic waters of the Indian River Lagoon (IRL), decreases in overall
shellfish size have been reported, which may be related to coastal acidification. To
understand the relationship between acidification and eutrophication, water samples from
20 sites spanning the IRL were collected and analyzed for dissolved nutrients and omega
values in spring (dry season) and fall (wet season), 2016-2017. Additionally, three sites
were sampled weekly to observe temporal variability of nutrients and omega values. For
the IRL-Wide sampling, sites with higher dissolved nutrient concentrations showed lower
omega values with significant negative relationships. Both sampling programs showed an
overall positive linear relationship between salinity and omega values. This work
suggests that salinity and dissolved nutrients have implications for acidification in the
IRL and must be considered for future water quality, shellfish and coral reef restoration.

Contamination of recreational waters with fecal waste, indicated by the presence of
enterococci, can have consequences for human and ecosystem health. The difficulty in
determining the extent and origin of fecal pollution in dynamic estuarine systems is
compounded by contributions from sources including septic tanks and agricultural runoff.
This study investigated fecal pollution at five sites with variable hydrological conditions
in the St. Lucie Estuary and Indian River Lagoon. The distribution and occurrence of
enterococci was assessed using traditional cultivation. A human-associated microbial
source tracking assay was validated and applied in these estuaries using qPCR. Results
demonstrated a correlation between enterococci concentrations, rainfall, and salinity. The
human-associated assay was sensitive and specific in the lab; however, human fecal
pollution was not detected in the field even though samples contained high levels of
enterococci. This study highlights the importance of expanding the range of water quality
assessment.