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		Research Larval transport through barrier island inlets The South Atlantic Bight Recruitment Experiment (SABRE) was a multidiciplinary study of physical and biological mechanisms for larval recruitment. Some of the key findings of this work are in the publications listed below. CHURCHILL, J. H., J. O. BLANTON, J. L. HENCH, R. A. LUETTICH, JR., AND F. E. WERNER, 1999. Flood tide circulation near Beaufort Inlet, North Carolina: Implications for larval recruitment. Estuaries, 22(4): 1057-1070. Abstract Drifter tracks and shipboard CTD observations have revealed a number of distinct features of the flood tide circulation carrying water through Beaufort Inlet, North Carolina. One of the most noteworthy of these features is a nearshore jet in the flow carrying water to the inlet on a flood tide. Characterized by a shoreward increase in longshore flow, the jet produces a narrow coastal zone over which water is carried into the inlet. The jet appears to be principally a tidal phenomenon, as it is closely reproduced by a tidally-driven barotropic numerical model. The model results also indicate the jet may be a near-inlet feature. Model simulations of spring tide conditions show the jet confined to within 4 km of the inlet mouth. Another observed phenomenon, which is reproduced by the tidal model, is a distinct splitting of the flow entering the inlet, in which water passing through a particular inlet segment tends to move up-estuary along a well-defined path. An observed flow feature not reproduced by the tidal model is an eastward skew of the region over which water is drawn into the inlet on a flood tide. This asymmetry is unrelated to the local wind. Modeling results from a previous study suggest it may be due to convergent flow at the edge of the low salinity plume issuing from the inlet. Taken together, the results of this and other recent studies in the Beaufort Inlet region reveal the importance of near-shore currents on the eastern side of the inlet in delivering oceanic-spawned larvae to the estuarine system connected to the inlet. BLANTON, J. O., J. AMFT, R. A. LUETTICH, JR., J. L. HENCH, AND J. H. CHURCHILL, 1999. Tidal and subtidal fluctuations in temperature, salinity and pressure for the winter 1996 larval ingress experiment - Beaufort Inlet, NC. Fisheries Oceanography, 8(Suppl.): 134-152. Abstract A multidisciplinary field experiment was conducted to compare water properties, larval abundances, and transport and retention processes at Beaufort Inlet and two channels leading to the estuarine nursery grounds. Temperature, salinity and subsurface pressure were monitored in situ for a six-week period during March and April 1996 in each channel. Intensive sampling was performed during two near-tide periods when water mass conditions in the estuary were significantly different. Currents were stronger in the eastern channel during both experiments. Ebb currents were stronger than flood in both channels. Decreasing subtidal sea level appeared to account for the stronger ebb currents. Subtidal sea level in the inlet responded optimally to north-south (along the inlet axis) wind stress and along a line 15 degrees clockwise of north-south. This direction closely parallels the channel axis of Core Sound and may provide an efficient conduit to carry large volumes of low-salinity Pamlico Sound water into the estuarine complex when winds blow south in this sector. The tidal stream in Beaufort Inlet sets up strong cross-inlet gradients by the advection on the east side of higher salinity shelf water and advection on the west side of Beaufort Inlet plume water. The axial fronts produced by differential advection of these two water masses might play some role in redistribution larvae in one tidal stream to another. CHURCHILL, J. H., R. B. FORWARD, R. A. LUETTICH, J. L. HENCH, W. F. HETTLER, L. B. CROWDER, AND J. O. BLANTON, 1999. Circulation and larval fish transport through a tidally dominated estuary. Fisheries Oceanography, 8(Suppl. 2): 173-189. Abstract In March 1996 two surveys of larval fish abundance and water flow were carried out within the estuarine region near Beaufort Inlet, NC. Each survey extended over two full semidiurnal tidal cycles and included measurements of larvae concentration and velocity distribution at several locations. There was a large across-channel variation in the subtidal flow passing through Beaufort Inlet, with net inflow over the eastern and central portions of the inlet and net outflow on the western side of the inlet. This pattern was consistent with moored current meter measurements of a previous study, and was reproduced by a numerical model circulation forced only by the M2 tide. A net ingress of larvae from the open ocean into the estuary was observed during both surveys. Most larvae entered the estuary over the eastern and central portions of the inlet, where the subtidal flow was up-estuary. However, the mean circulation played a minor role in the net movement of larvae into the estuary. Rather, net-up-estuary transport of larvae was principally due to variation of larval abundance with tidal flow; with abundance during flood tide usually far exceeding ebb tide abundance. The mode of transport was likely driven by behavioral response to tidal flow in which larvae tended to descend to the bottom on falling tides and reside throughout the water column on rising tides. LUETTICH, JR., R. A., J. L. HENCH, C. W. FULCHER, F. E. WERNER, B. O. BLANTON, AND J. H. CHURCHILL, 1999. Barotropic tidal and wind-driven larval transport in the vicinity of a barrier island inlet. Fisheries Oceanography, 8(Suppl. 2): 190-209. Abstract Fish species such as Atlantic menhaden (Brevoortia tyrannus) must often transit relatively small barrier island inlets to move from their continental shelf spawning grounds to estuarine nurseries, where they spend their juvenile phase. Physical transport through these inlets is strongly influenced by tides, winds, local geometry and bathymetry, and can be very different from that occurring on the shelf. In March 1996, an extensive multidisciplinary field experiment was conducted to identify larval transport pathways in the vicinity of Beaufort Inlet, NC (Blanton et al., 1999; Churchill et al., 1999; Forward et al., 1999). One of the most interesting results from the field study was significant spatial inhomogeneity in the larval catches (Forward et al., 1999). This paper describes a computer modeling study of tidal and wind-driven circulation and accompanying larval transport characteristics in the vicinity of Beaufort Inlet. Primary conclusions are as follows: (i) tidal currents are quite effective at creating net larval transport into the inlet; (ii) in the absence of wind forcing, to explain the spatial distribution of larval catches observed in the field experiment, the primary source of larvae must have been to the east of the inlet; (iii) the spring/neap cycle accounts for a variation of approximately 40% in larvae ingress; (iv) only a few wind directions enhance larvae ingress over the case of purely tidal forcing - wind blowing toward the north enhances ingress at the surface, and winds blowing toward the south and the east enhance ingress at the bottom; (v) if larvae are evenly distributed in space outside the inlet, then strong east wind (such as 10 m/s) can cause larvae to move through the inlet in a way that is consistent with the larval catches in the field experiment. However, local wind records revealed that no significant eastward-blowing winds occurred during or immediately preceding the field experiment.