Surface plankton tows were completed at select reef passes and lagoons over five weeks on the island of Mo’orea, French Polynesia. Differences in zooplankton species richness and abundance were analyzed based on location, salinity, and tide. Reef passes and lagoons varied in the average abundance of zooplankton as well as having different species prevalence. Lab experiments tested individual groups’ tolerance to varying salinity levels that were found in Cook’s Bay. There was a significant drop in copepod and crustacean nauplii populations when exposed to lower salinity levels.