Short-term dispersal of an intentionally-released patch of larval Mercenaria spp. in the Indian River Lagoon, Florida, USA

July 1998 approximately 2.5 x 10(8) of recently-spawned Mercenaria spp. larvae were intentionally released in the northernmost basin of the Indian River Lagoon, Florida, to characterize the initial dispersion from a point source at time scales of hours to days. Larval densities measured with a quantitative molecular method indicated ambient concentrations were enhanced by 10 larvae L-I near surface drifters released with the larvae. Surface distributions from samples collected near the drifters indicate that larval patches developed during the first day. Diffusive processes evaluated from dye releases yield apparent diffusivity coefficients that suggest diffusive processes could spread larvae over several km(2) within 2 d. Our observations suggest that high-resolution methods for mapping larvae are essential to better resolve spatial distribution evolution at time scales of hours to days, and spatial scales of tens to hundreds of meters. This capability could better define the temporal evolution of larval distributions following a mass spawning event.