Marine populations are typically connected over greater spatial scales than their terrestrial counterpartsdue to many species having a highly dispersive, planktonic larval phase. However, high levels of larvalmortality in the plankton may reduce connectivity between populations. The effect of turbulence onlarval mortality was investigated under natural conditions in a field experiment. Larvae were collectedbefore and after being subjected to turbulent tidal flow from a marine reserve, with differential mortalitybeing observed between taxa. Thin-shelled veligers of gastropods and bivalves showed significantlyincreased mortality, while barnacle nauplii and cyprids, bryozoan cyphonaute larvae and polychaetetrochophores showed no effect of turbulent tidal transport. Where appropriate, marine reserve designshould account for the reduced connectivity between populations associated with turbulent tidal transportbetween reserve and adjacent areas.