Summary of the data collection and analysis.

Of the 83 larvae observed, 83% showed significant directionality (significant first order Rayleigh test). At the population level, swimming speeds were different between plume and ocean for both families (10% and 5% confidence levels for Apogonidae and Pomancentridae, respectively). Orientation was significant for Pomacentridae larvae in plume water only and was Westward (268°), while swimming alongshore (nearly perpendicular to the direction of the reef atoll, at 98°).