Lethal and sublethal impacts of a micropredator on post-settlement Caribbean reef fishes
- 253 Downloads
The transition from a planktonic larval stage to a benthic or demersal juvenile stage, “recruitment”, is a crucial event in the life history of coral reef fishes, and has a strong influence on population size. Predation by piscivorous fishes is thought to be the main determinant of recruitment success, and has received the most attention. However, recent studies suggest that recently settled reef fishes are also an important target of micropredation from blood-feeding ectoparasites which may have significant lethal and sublethal effects. In this study, we quantified the relationship between levels of infestation by gnathiid isopods and mortality rates among juveniles of three species of reef fishes as a function of body mass both within and among species. We found that a single gnathiid isopod larva could kill fish of all three species shortly after settlement, up to 0.116 g [18 mm fork length (FL)] in French grunt (Haemulon flavolineatum), 0.027 g (15 mm FL) in masked goby (Coryphopterus personatus) and 0.01 g (9 mm FL) in beaugregory damselfish (Stegastes leucostictus). For juvenile S. leucostictus, we also compared the ability of fish to defend a territory when infested with a sublethal number of gnathiids versus uninfected individuals. Uninfected fish were significantly more likely to win-pairwise contests versus infected fish. These findings suggest that gnathiids can significantly impact juvenile coral reef fish survival, and affect population dynamics well past the settlement stage.
KeywordsParasite Competition Gnathiid isopod Mortality Recruitment
We thank J. Jossart, J. Kisabeth, T. Santos, D. Ashaab, and M. Nicholson, for help with collecting specimens and maintenance of the gnathiid colony. We also thank P. Jobsis, R. Nemeth, and the staff of the University of the Virgin Islands’ McLean Marine Science Center. Funding was generously provided by U.S. National Science Foundation Grants OCE-121615 and OCE-1536794 (PC Sikkel, PI), and Puerto Rico Sea Grant (R-31-1-14, PC Sikkel, PI). We are grateful to the two anonymous reviewers who provided constructive comments for improvement of the manuscript. This is contribution #198 from the University of the Virgin Islands Center for Marine and Environmental Studies, and contribution number 265 from the NWU Water Research Group.
Author contribution statement
JCS collected specimens and performed experiments. PCS conceptualized and developed the project, and acquired all funding and permits. PCS, JCS, DMH designed the experiments. JCS, DMH, TLB performed data analyses, with input from PCS. JCS led the writing of the manuscript with significant input by PCS, DMH, TLB.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
- Carlsson AM, Mastromonaco G, Vandervalk E, Kutz S (2016) Parasites, stress and reindeer: infection with abomasal nematodes is not associated with elevated glucocorticoid levels in hair or faeces. Conserv Physiol 4(1):cow058. https://doi.org/10.1093/conphys/cow058 PubMedPubMedCentralCrossRefGoogle Scholar
- Combes C (2001) Parasitism. The ecology and evolution of intimate interactions. University of Chicago Press, ChicagoGoogle Scholar
- Grutter AS, Blomberg SP, Fargher B, Kuris AM, McCormick MI, Warner RR (2017) Size-related mortality due to gnathiid isopod micropredation correlates with settlement size in coral reef fishes. Coral Reefs 1:1–11Google Scholar
- Itazawa Y, Takeda T, Yamamoto K, Azuma T (1983) Determination of circulating blood volume in three teleosts, carp, yellowtail and porgy. Jpn J Ichthyol 30(1):94–101Google Scholar
- Kuris AM, Hechinger RF, Shaw JC, Whitney KL, Aguirre-Macedo L, Boch CA, Dobson AP, Dunham EJ, Fredensborg BL, Huspeni TC, Lorda J, Mababa L, Mancini FT, Mora AB, Pickering M, Talhouk NL, Torchin ME, Lafferty KD (2008) Ecosystem energetic implications of parasite and free-living biomass in three estuaries. Nature 454:515–518PubMedCrossRefGoogle Scholar
- Lee HB, Blaufox MD (1985) Blood volume in the rat. J Nucl Med 25:72–76Google Scholar
- Randall JE (1967) Food habits of reef fishes of the West Indies. Study Trop Oceanogr 5:665–847Google Scholar
- R Core Team (2016) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. http://www.R-project.org/. Accessed 25 Aug 2016
- Smit NJ, Davies AJ (2004) The curious lifestyle of the parasitic stages of gnathiid isopods. Adv Parasitol 46:229–240Google Scholar
- Strathmann RR, Hughes TP, Kuris AM, Lindeman KC, Morgan SG, Pandolfi JM, Warner RR (2002) Evolution of local-recruitment and its consequences for marine populations. Bull Mar Sci 70(1):377–396Google Scholar
- Waldner RE, Robertson RD (1980) Patterns of habitat partitioning by eight species of territorial Caribbean damselfishes (Pisces:Pomacentridae). Bull Mar Sci 30:171–186Google Scholar