Our lab sampled nearly 1,500 fishes, which revealed that 51 fish species inhabit the main channel of the Pascagoula River and its forested floodplain during the dry (summer) and flood (winter and spring) seasons. Interestedly, flooded forests harbor a distinctive and more taxonomically and functionally diverse fish assemblage relative to the river channel. During the dry season, habitats within the forested floodplain such as sloughs, oxbow lakes, and canals remain flooded and provide high-quality habitat for fish as demonstrated by observed levels of dissolved oxygen and nitrates comparable to those in the river channel. The average depth inside flooded forest habitat during the dry season was 1.3 m. A remarkable finding was that large fish use the flooded forest during the dry season as climate refugia when they escape from the warmer water in the main river channel during the hot Mississippi summer.
Interestedly, seasonal flooding facilitates the longitudinal movement of fishes across floodplain habitats throughout the entire 100 km river reach. Our diet analyses demonstrated that fish consume various foods within the flooded forest, including terrestrial insects. Crayfish, however, seems to be a staple in the diet of many predatory fishes during the flood season. We are using biomarkers to build a food web for the Pascagoula.