Nekton Density Patterns in Tidal Ponds and Adjacent Wetlands Related to Pond Size and Salinity

We examined the distribution of nekton across the marsh landscape using a 1-m(2) drop sampler to compare nekton densities across three different salinity zones (intermediate, brackish, saline), three pond sizes (diameter <40 m=small, similar to 250-300 m=medium, >750 m=large), and two habitat types (pond, adjacent marsh) in the Barataria Bay Estuary, Louisiana. Nekton assemblages of ponds and the adjacent marsh appeared to be structured by the responses of individual species to the estuarine salinity gradient at the landscape scale and to pond habitat attributes locally. Our results indicate that ponds in the brackish and saline zones are more important nursery areas for most fishery species than ponds in the intermediate zone. Medium and large ponds supported higher densities of most species than small ponds. Most species of nekton were associated with vegetation structure, and individuals of these species were either concentrated among plant stems at the marsh edge or within submerged aquatic vegetation in ponds.