Impact of Hurricane Harvey on Galveston Bay Saltmarsh Nekton Communities

Coastal saltmarshes are a unique habitat at the interface of tidal coastal waters and freshwater inflow providing foraging and nursery habitat for a dynamic nekton community. Saltmarshes are particularly exposed to natural disturbances such as tropical storms, which can cause shifts in water chemistry and nekton community composition. Hurricane Harvey resulted in widespread flooding and record freshwater inflow into Galveston Bay in late August 2017. This study examined the influence of the hurricane on nekton community composition of two saltmarshes in Galveston Bay, TX. Nekton were monitored from February to December 2017 using minnow seines and Breder traps. Reduced abundance and increased diversity, despite the overall reduced number of taxa of the nekton community, were documented following the hurricane. Exacerbating these differences were reduced catches of the numerically dominant daggerblade grass shrimp, Palaemonetes pugio, following the event. For some key dominant species, a significant reduction in length was measured between pre- and post-disturbance; therefore, it is likely that new recruits, rather than the return of displaced adults, drove the community recovery. A complete recovery to a pre-disturbance state will likely require at least a full year due to seasonal recruitment patterns of many of the saltmarsh nekton species. Short-term but large-scale natural disturbances can significantly impact saltmarsh nekton communities, but because of their dynamic nature, they are generally resilient.