Climate effects on fish diversity in the subtropical bays of Texas

Abstract

Climate change affects temperatures, sea level, and salinities, all of which can affect fish distributions. In order to assess the impact of climate change on the marine fish communities of Texas, fish diversity response to climate variables was modeled. Leveraging 33 years of gillnet survey data from eight major bays along the coast of Texas, asymptotic Shannon diversity was estimated for each bay, season, and year using rarefaction analysis. This allowed for the estimation of spatial, temporal, and seasonal trends in fish diversity. In order to assess the impact of climate-related variables on the fish communities of Texas, we associated the Shannon diversity index with environmental variables using a repeated measures model approach. We found significant increasing trends in fish diversity across all eight bays in fall and six of eight bays in spring. Among the variables identified as significant, temperature, salinity, and sea level stood out as most important for driving the increase in fish diversity. Our results suggest that observed increases may be attributable to changing habitat availability resulting from sea-level rise and increasing winter temperatures. Mangrove expansion and warmer winters are likely allowing for range expansion by tropical species, driving the observed increase in fish diversity.