Long-term patterns in use of an intertidal salt marsh basin by flatfishes in South Carolina, USA

Maintaining continuity in the methodology for collecting nekton over long periods is difficult, and such datasets are uncommon.  We assessed patterns of flatfish habitat use and the relationships with environmental conditions over 19 years using the same gear type.  Flatfishes were collected from an intertidal salt marsh basin in North Inlet estuary, South Carolina, USA using a bag seine during low tide.  Semi-monthly samples from 1984 to 2002 yielded six species of flatfishes that were mostly juveniles.  Blackcheek tonguefish Symphurus plagiusa were most abundant and experienced a significant long-term increase in numbers over the years correlated with an increase in water temperature.  The second-most abundant species, the southern flounder Paralichthys lethostigma, experienced no significant change in number over the course of the study.  The bay whiff Citharichthys spilopterus was the third-most abundant species and had high annual variability with no overall trend over time or with temperature.  No long-term pattern was found for the summer flounder Paralichthys dentatus.  Overall, multiple species used the intertidal habitat during the warmest months, and although arrival times generally coincided, abundances were not often correlated with increases in temperature.  This suggests that independent factors affected recruitment to the estuary.