Effects of Hurricane Harvey on the Trophic Status of Juvenile Sport Fishes (Cynoscion nebulosus, Sciaenops ocellatus) in an Estuarine Nursery

摘要

Understanding the implications of environmental disturbance is of growing importance as climate change and extreme weather events increasingly threaten estuaries and other coastal ecosystems. Among species at risk in estuarine habitats, sport fishes are of particular interest to conservation and management agencies, because of their ecological and economic value. Here, we evaluate the effects of Hurricane Harvey on the abundance, diet, and body condition of age-0 red drum (Sciaenops ocellatus) and spotted seatrout (Cynoscion nebulosus) in Powderhorn Lake, a nearshore estuary in Texas, USA. Catch data from seines indicated that the abundances of age-0 red drum and spotted seatrout were not affected by the hurricane in the study system, but stomach contents and morphometric data show that diet and body condition changed after the event. Both species exhibited declines in body condition based on weight-length ratios, and diets included a greater proportion of invertebrates (i.e., shrimp, crab) post-disturbance, which may have been attributed to changes in fish assemblage structure within the estuary. Trophic niche overlap between age-0 red drum and spotted seatrout also decreased by up to 50% after the event, potentially serving as a mechanism to reduce competition in response to decreased prey availability. Thus, while more easily measured indicators of resistance/resilience (i.e., abundance) did not indicate effects of Hurricane Harvey on sport fishes in Powderhorn Lake, body condition and diet suggest impacts were observed among age-0 fish. Declines in body condition and greater reliance on crustacean prey could have implications for survival, fitness, and harvestability, particularly if more energy is allocated to maintenance during recovery, rather than growth.