Bull Mar Sci. 91(4):479–487. 2015 coral reef paper http://dx.doi.org/10.5343/bms.2015.1023 Micropredation by gnathiid isopods on settlement- stage reef fish in the eastern Caribbean Sea 1 Department of Biological John M Artim 1 Sciences and Environmental 2 Sciences Program, Arkansas Joseph C Sellers State University, State Paul C Sikkel 1, 3 * University, Arkansas 72467. 2 Center for Marine and Environmental Studies, University of the Virgin Islands, ABSTRACT.—The transition from a planktonic larval 2 Brewers Bay, St. Thomas, USVI stage to a benthic or demersal juvenile stage is a crucial event 00802. in the life history of coral reef fishes, and recruitment success has a strong influence on reef-fish population size. Post- 3 Water Research Group, Unit for Environmental Sciences settlement predation is thought to limit recruitment success. and Management, North-West Most studies on post-settlement predation have focused on University, Potchefstroom 2520, piscivorous reef fishes. However, recent studies in the tropical South Africa. Pacific Ocean suggest that blood-feeding ectoparasites may * Corresponding author email: also be an important source of predation. Here we provide <
[email protected]>, phone: further evidence that a gnathiid ectoparasite is capable of 870-972-3296, fax: 870-972-2638. such “micropredation” on settlement-stage fish in the eastern Caribbean Sea. On 12 occasions in May–August, 2014 and 2015, during plankton light-trap recovery, we observed post- settlement fishes from the families Apogonidae, Bothidae, Gobiidae, Labrisomidae, and Tripterygiidae with attached ectoparasitic juvenile gnathiid isopods. In one laboratory experiment in which 10 settlement-stage French grunt, Haemulon flavolineatum (Desmarest, 1823), were fed upon by an average of one gnathiid per fish, all fish died compared to none in the control group.