The coral reef at Cahuita National Park in the Caribbean coast of Costa Rica represents very diverse marine ecosystem. Most of this diversity knowledge has been the result of benthic surveys, while very little is known from pelagic studies. A zooplankton survey sampling was conducted monthly from September 2010 to August 2011, finding new records of marine invertebrates: 32 for the Caribbean coast of Costa Rica, seven for Costa Rican water and 16 for the Caribbean coast of Central America. These reports include the hoplitomella larva of the sponge Thoosa sp., larval stages of three lophophorates, seven families, five genera and six species of polychaetes, a juvenile of the lancet Branchiostoma (Phylum Chordata, Subphylum Cephalochordata) and four pelagic chordates. Analyzing the zooplankton of Cahuita, is an essential approach to studying not only the diversity, but also enhances the possibility of better understanding the ecological goods and services that the coral reef can provide.
Keywords: Cahuita, coral reef, marine invertebrate larva, polychaetes, zooplankton.