Saltmarsh as habitat for fish and nektonic crustaceans: Challenges in sampling designs and methods

This is a review of research into the ecological role of saltmarsh as habit at used directly by fish and nektonic crustaceans such as shrimp (prawns) a nd portunid crabs. The quality of information about direct use of saltmarsh es:by nekton is poor, with even the most influential works suffering from o bvious limitations. Attempts to generalize about nekton use of saltmarshes are hampered by sampling difficulties, poor sampling design, and inconsiste nt reporting of flooding regime and landscape structure. The difficulty in sampling; nekton from shallow, vegetated marsh flats while inundated contri butes to the fragmentary results of nekton work. A range of sampling method s have been described that vary in portability, size, amount of above-groun d structure, escape rates of nekton, and expense; none has yet become stand ard. Poor experimental design in studies of saltmarsh nekton includes lack of replication, limited spatial scale, and lack of baseline data before man agement changes are made. Attempts to determine effects on commercial fishe ries of losses in area or quality of saltmarsh by correlations between catc h data and marsh loss should use active adaptive management. A second type of study, aimed at understanding how the saltmarsh is important to fisherie s, can be tackled usefully at a smaller scale. To assist in the comparison of results from different studies, flooding regime should be reported as a proportion of time the marsh is submerged, and landscape structure as propo rtions of the marsh that are covered by intertidal flats, pools and drainag e creeks. Flooding regime and landscape structure at the sites and at the t ime of sampling should then be put in the context of the typical pattern fo r the marsh under study.