Effect of Fragmentation and Habitat Type on Coastal Nekton in Mississippi

Coastal wetlands are extremely productive ecosystems that support an abundance of organisms at higher tropic levels. Coastal wetlands also act as important buffers from storms and help protect major cornerstones of coastal economies, such as tourism and fisheries. Despite the clear need for the protection of these habitats, anthropogenic use of coastal wetlands has increased in frequency and intensity, resulting in the fragmentation of once continuous habitats. A central challenge to assessing the impact of marsh fragmentation is the lack of quantitative distribution and abundance data from specific habitat types. This is especially true for species that are not commercially or recreationally harvested and are, therefore, not regularly monitored by state and federal resource management agencies. This study makes use of quantitative density, habitat use, and distribution data for non-harvested marsh nekton collected in oligohaline marshes (salinity 0.5-5ppt) of coastal Mississippi. To assess how nekton assemblages varied by habitat, fragmentation level and position in patch (core vs. edge), four sites along coastal Mississippi were sampled in the summers of 2014 and 2015. Nekton were sampled in adjacent patches of submerged aquatic vegetation and emergent vegetation using a 1 m2 throw trap. Marsh patch fragmentation was quantified using aerial pictures taken with a GoPro camera secured to the end of a 20ft pole. Points around the patch were digitized in TPS software and analyzed using R. The results of this study indicate that diversity and density of nekton in Mississippi marshes vary significantly based on habitat type