Marsh Restoration Effect on Nekton Communities

The increase of protecting salt marshes has accelerated throughout the world due to coastal protection, but understanding how communities of nekton (aquatic animals, such as fish and invertebrates that are capable of movement independently of tides and/or current) are affected by replenishment efforts is extremely limited (Roman et al., 2002). These replenishment practices are firstly aimed at replacing a thin layer of material over targeted areas of the marsh to increase its elevation; secondly replenishment efforts are aimed to concentrate fill material to expanding marsh pools by elevating the substrate to the same level of adjacent marshes. Quantitative results are imperative to understanding nekton assemblage within marsh environments to better understand restoration practices, while also evaluating current and future restoration practices.

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Killifish are considered the most structurally important and residential species within salt marsh aquatic sub-habitats (Collette and Klein-MacPhee 2002). Killifish are considered to be the most important species due to their dominance, productivity, and have been shown to be an indicator of early stages of a declining marsh environment over other nekton assemblage throughout marsh sub-habitats (Able et al. 2007). Mummichogs may disperse over the marsh surface if and when water is present. However, if water does not disperse over the marsh surface in the event of high flooding events, killifish occupy sub-habitats such as tidal creeks, ditches, and pools that are embedded deep in marsh habitat. These sub-habitats have been shown to be important forging areas for these species (Allen et al., 1994). Other important species that may contribute to food web linkage and production of the nekton community found within marsh are daggerblade grass shrimp (Palaemonetes pugio), Atlantic silversides (Menidia menidia), striped killifish (Fundulus majalis), and sheepshead minnows (Cyprinodon variegatus). Understanding abundance and dominance of nekton is fundamental in understanding physical tolerances of nekton survival. ​

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References:​
Collette, B.B., and G. Klein-MacPhee (eds.) 2002. Bigelow and Schroeder’s Fishes of the Gulf of Maine. Washington: Smithsonian Institution Press. 
Allen Elizabeth A., Fell Paul E., Peck Myron A., Gieg Jennifer A., Gutike Carl R., Newkirk Michael D., Gut Contents of Common Mummichogs, Fundulus heteroclitus L., in a Restored Impounded Marsh and in Natural Reference Marshes. Estuaries. Vol. 17, No. 2, pp 462-471. June 1994.
Able, K.W., J.H. Balletto, S.M. Hagan, P.R. Jivoff, and K. Strait. 2007, Linkages between salt marshes and other nekton habitats in Delaware Bay, USA. Reviews in Fisheries Science 15: 1-61. 
Roman, Charles T., Raposa, Kenneth B., Adamowicz Susan C., James-Pirri, Mary-Jane, Catena, John G. Quantifying Vegetation and Nekton Response to Tidal Restoration of a New England Salt Marsh. Restoration Ecology Vol. 10, No. 3, pp. 450-460. September 2002