Dataset: Parasite abundance data collected from coral reef fishes across 19 islands in the central equatorial Pacific from 2009 to 2021

Fish collection

We sampled 17 species of coral reef fishes (Acanthurus nigricans, Cephalopholis argus, Cephalopholis urodeta, Chromis iomelas, Chromis margaritifer, Ctenochaetus marginatus, Ctenochaetus striatus, Paracirrhites arcatus, Plectroglyphidodon dickii, Pseudanthias bartlettorum, Pseudanthias dispar, Pseudanthias mooreanus, Pseudanthias olivaceous, Pseudianthias pascalus, Pseudanthias spp., Stegastes aureus, Stegastes fasciolatus) across three archipelagos and 19 islands (Jarvis, Kingman, Kiritimati, Palmyra, Tabuaeran, and Teraina in the Northern Line Islands; Flint, Malden, Millennium, Starbuck, and Vostok in the Southern Line Islands; Huahine, Moorea, Raiatea, Rangiroa, Tahiti, Takapoto, Tetiaroa, and Tikehau in French Polynesia), for a total of 5,344 fish.. These 17 broadly distributed host species represent a large spectrum of body sizes, including multiple taxonomic and trophic groups. Due to the limitations on the natural geographic ranges of some species, not all species could be sampled on all islands; when we found that a target species was not present on a given island, we sampled a close congener instead (e.g., Stegastes fasciolatus instead of Stegastes aureus). In general, fish greater than 10 cm in total length were collected using three-pronged spears, while hand nets were used to capture fish smaller than 10 cm in length. Most fish were sampled from depths of 8 to 18 m from the leeward forereef of each island. After collection, fish were humanely euthanized using protocols in UC San Diego IACUC protocol #S09392, which provided ethical approval for this study. We then recorded morphometric data, including the total length of each fish (mm), before freezing fish immediately after collection. Fish were transported frozen back to the laboratory and were kept frozen until they were thawed for parasitological examination.

Parasite abundance assessment

Parasites were identified and counted using standard dissection methods optimized to detect the majority of metazoan parasites, with the exception of mobile skin parasites and micropredators (which often drop off the host after capture), as well as myxozoans. The protocol was optimized to the morphology of each fish species and standardized within species. We assessed fish using a stereomicroscope, individually examining the fins, gills, eyes, heart, liver, spleen, gonad, muscle, skin and intestines. Parasites were identified using taxonomic keys to the lowest possible taxonomic level and were classified as either direct or complex life cycle parasites using those keys. The detailed parasitological detection methodology used for each fish species is presented in Appendix E of Wood et al. 2014:

Wood CL, Sandin S, Zgliczynski B, Guerra AS, and Micheli F. 2014. Fishing drives declines in fish parasite diversity and has variable effects on parasite abundance. Ecology 95: 1929-46.