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White shrimp ( Litopenaeus setiferus) fisheries-independent and fisheries-dependent landings can be highly variable and may be related to environmental factors that influence growth, mortality, and survival. We used linear regression analysis to look for potential relationships between environmental and white shrimp catch-per-unit-effort (CPUE) data collected from the Ashepoo-Combahee-Edisto (ACE) Basin National Estuarine Research Reserve (NERR) for four critical months in the shrimp life cycle. This analysis used data from white shrimp fisheries-independent CPUE (2002 to 2014) and water quality and meteorological variables for August (juvenile), December (sub-adult), March (adult), and April (spawning adult). The results showed that shrimp CPUE was mainly correlated with water temperature, salinity, and dissolved oxygen concentration collected through the ACE Basin NERR's System-Wide Monitoring Program (SWMP), but offshore wind, precipitation, and intra-annual CPUEs also partially explained the variability in monthly CPUEs. Black gill prevalence was correlated with water temperature and salinity. Additionally, our analysis found that winter water temperatures of ≤11 °C were correlated with reduced shrimp abundance the following spring. Ultimately, managers would like to successfully predict white shrimp stock abundance throughout fishing seasons based on environmental conditions. This study is a first step in identifying the environmental variables that may be useful in predicting white shrimp CPUE in the South Atlantic Bight. The techniques employed here can serve as a basis for predicting and managing other wild annual fisheries stocks. [ABSTRACT FROM AUTHOR]

In the tidal creeks of the southeastern United States, the numerically and ecologically dominant macrobenthic organisms are typically oligochaetes. Due to their relatively small size and difficult taxonomy, little is known about the short-term and seasonal changes in the oligochaetes of tidal creeks. This study presents a report of the spatial and temporal changes of the oligochaete taxa within and between two tidal creeks in southern South Carolina, at monthly intervals over a 13-month period. These changes are framed within the reference of monthly changes in benthic chlorophyll a, sediment composition, and porewater ammonia, as well as in the perspective of seasonal changes in the entire tidal creek macrobenthic community. The most abundant oligochaete found in this study was the tubificid Monopylephorus rubroniveus, followed by the naid Paranais litoralis and the tubificids Tubificoides heterochaetus and T. brownae. All of the oligochaetes exhibited strong month-to-month and spatial changes, indicative of changes in water quality and sediment habitat characteristics (e.g., low dissolved oxygen, high benthic chlorophyll a). There were significant correlations between the abundance of most species and either benthic chlorophyll a concentration or the silt-clay fraction of the sediment. Looking at short-term changes in this rapidly changing component of the macrobenthic community provides insight not only into the ecology of the oligochaetes, but also into the changes in the tidal creek ecosystem and their potential effects on other biota. [ABSTRACT FROM AUTHOR]

Measurements of the annual production of the oligochaete Monopylephorus rubroniveus, microphytobenthos, pore-water ammonia, sediment composition, and water quality were made from January through December 2001 in the upper and lower reaches of two tidal creeks in southeastern South Carolina. Secondary production of M. rubroniveus was greater in the shallow upper reaches of tidal creeks (1.0-10.5 g ash-free dry weight [AFDW] m-2 yr-1) than in the lower reaches (0.05-0.2 g AFDW m-2 yr-1), as were benthic chlorophyll a levels and pore-water ammonia concentration. Production of M. rubroniveus was greater in both reaches of Okatee Creek (0.1-10.5 g AFDW m-2 yr-1) than in Malind Creek (0.05-2.0 g AFDW m-2 yr-1). The only significant difference in environmental characteristics between the two creeks was a greater incidence of hypoxia (dissolved oxygen < 28% air saturation) in Malind Creek than in Okatee Creek, 5% of all records observed versus 0.3%, respectively. The rates of production estimated for M. rubroniveus in these creeks were relatively high compared with similar macrobenthos in other environments. Furthermore, the pattern of production within and between creeks provides a basic understanding of energy and material flows out of these important ecosystems and the processes that influence them. [ABSTRACT FROM AUTHOR]

Twenty-three headwater tidal creeks draining watersheds representative of forested, suburban, urban, and industrial land cover were sampled along the South Carolina coast from 1994 to 2002 to: (1) evaluate the degree to which impervious land cover is an integrative watershed-scale indicator of stress; (2) synthesize and integrate the available data on linkages between land cover and tidal creek environmental quality into a conceptual model of the responses of tidal creeks to human development; and (3) use the model to develop recommendations for conserving and restoring tidal creek ecosystems. The following parameters were evaluated: human population density, land use, impervious cover, creek physical characteristics, water quality, sediment chemical contamination and grain size characteristics, benthic chlorophyll a levels, porewater ammonia concentration, fecal coliform concentration, and macrobenthic and nekton population and community characteristics.The conceptual model was developed and used to identify the linkages among watershed-scale stressors, physical and chemical exposures, and biological responses of tidal creeks to human development at the watershed scale. This model provides a visual representation of the manner in which human population growth is linked to changes in the physiochemical environment and ultimately the nursery habitat function of tidal creeks and the safety of seafood harvested from headwater tidal creeks. The ultimate stressor on the tidal creek ecosystem is the human population density in the watershed and associated increases in the amount of impervious land cover. Measurable adverse changes in the physical and chemical environment were observed when the impervious cover exceeded 10–20% including altered hydrography, changes in salinity variance, altered sediment characteristics, increased chemical contaminants, and increased fecal coliform loadings. Living resources responded when impervious cover exceeded 20–30%. The impacts on the living resources included reduced abundance of stress-sensitive macrobenthic taxa, reduced abundance of commercially and recreationally important shrimp, and altered food webs. Headwater tidal creeks appear to provide early warning of ensuing harm to larger tidal creeks, tidal rivers and estuaries, and the amount of impervious cover in a watershed appears to be an integrative measure of the adverse human alterations of the landscape. Through education and community involvement, a conservation ethic may be fostered that encourages the permanent protection of lands for the services they provide. [Copyright &y& Elsevier]