Abstract
Coastal lagoon and estuarine ecosystems’ structure and function are directly affected by fresh water inflows. Biscayne Bay’s biota is affected by the inflow of fresh water from surface and groundwater from the greater Everglades system. Historically, more spatially dispersed and persistent distribution of freshwater along the western shoreline has been largely replaced with controlled, pulsed point-source freshwater discharges that enter the bay through canals. Highly variable salinity regimes caused by these freshwater discharges can be detrimental to littoral communities. Floral and faunal species unable to withstand these fluctuations in habitat conditions may be excluded from these areas, while those that remain may face chronic physiological stress due to the variable salinity regimes. The Comprehensive Everglades Restoration Plan (CERP), and more specifically the Biscayne Bay Coastal Wetlands (BBCW), aims to preserve and restore natural coastal wetland habitats of central and southern Biscayne Bay by redistributing freshwater inflows to minimize point-source discharges. This will be achieved by constructing flow ways to restore near historic fresh water dispersion to the bay. Monitoring of the western shoreline epifaunal communities began in 2005, and this sampling program is currently ongoing as a component of the Integrated Biscayne Bay Ecological Assessment and Monitoring (IBBEAM) project. IBBEAM has been tasked with monitoring and assessing downstream effects of implementing CERP regionwide and implementing BBCW next to shore on western Biscayne Bay’s shallow near-shore water quality, submerged aquatic vegetation, epifaunal communities, and mangrove communities.
One species commonly encountered during epifaunal sampling is the Gulf pipefish (Syngnathus scovelli), an estuarine fish that exhibits sex role reversal and resides in sea grass beds. This species is considered an important indicator species of environmental conditions, due to its extreme tolerance to salinity variability. Its occurrence and density near shore have previously been reported, by IBBEAM, to be highest in polyhaline (18-30 ppt) salinity conditions. Abundance data collected over the past 12 years of consecutive, biannual epifaunal sampling was used to assess the density trends of the Gulf Pipefish in relation to salinity conditions. This study aims to relate potential Gulf Pipefish affinity and density limitation to salinity conditions observed at the time of sampling by providing data that could influence the implementation of CERP.