Influence of sequential hurricanes on nekton communities in a Southeast Florida estuary: Short-term effects in the context of historical variations in freshwater inflow

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We examined nekton community-level responses to Hurricanes Frances and Jeanne, which made landfall 20 d apart in the St. Lucie estuary in southeastern Florida in 2004. The passage of these storms contributed to large freshwater discharges that exceeded 150 m3 s−1, as well as estuary-wide reductions in salinity and near-hypoxic conditions in the North Fork of the estuary that persisted for several months. Although such environmental variations are not uncommon, seasonal patterns of community structure were disturbed throughout much of the estuary, likely in response to uncharacteristically-rapid reductions in salinity. Immediately following the hurricanes, abundances of several freshwater and oligohaline taxa (i.e., blue crabCallinectes sapidus, shadDorosoma spp., and ladyfishElops saurus) increased markedly in the inner estuary, while abundances of several other fishes (i.e., striped mulletMugil cephalus, white mulletM. curema, lookdownSelene vomer, pigfishOrthopristis chrysoptera, and pinfishLagodon rhomboides) declined. Nekton communities recovered quickly, and by spring, community structure throughout much of the estuary was indistinguishable from pre-hurricane conditions. Although nekton communities were resilient to hurricane-related disturbances, projected increases in Atlantic hurricane activity and associated freshwater discharges over the coming decades may test the resilience of estuarine communities in Florida.