Broadly, my research encompasses the interactions between marine organisms and their environment. My current emphasis is on the interaction between coral reef-associated fishes and their parasitic and mutualistic symbionts, and the ecological consequences of those interactions. My career, however, started with work on some of the largest marine organisms. As an undergraduate, I was privileged to participate in research on shark behavior in the Gulf of California under A.P. Klimley and A.J. Kalmijn, and smaller reef fishes in Panama under Eric Fischer. It was during my doctoral work under Mark Hixon that I transitioned to behavioral ecology of temperate reef fishes, particularly garibaldi damselfish. Then, during my postdoctoral work in the Virgin Islands and Barbados with Don Kramer and Wayne Hunte, I began my work on tropical damselfishes, and then to the parasites that infest them and other tropical reef fishes.
My research direction has been strongly fueled by a fascination with diel activity patterns in nature and by spending many hours observing the activities of reef organisms throughout the day and night (further fueled by my love of strong coffee!). My favorite place to be is on a coral reef at dawn! My most recent research projects have focused on the following:
1) The conflict between territory defense and extraterritorial movements in site attached organisms, and how it influences reproductive tactics and habitat selection.
Research Sites: Wrigley Marine Science Center, Santa Catalina Island, California; Bellairs Research Institute, Barbados
Collaborators: D.L. Kramer, S.E. Herzlieb Sample publications: Sikkel, P.C. 1995. Diel periodicity of spawning activity in a permanently territorial damselfish: a test of adult feeding hypotheses. Environmental Biology of Fishes 42: 241-251.
Sikkel, P.C. 1998. The influence of food competitors on mate-search tactics in a territorial marine fish. Behavioral Ecology 9: 439-444
Sikkel, P.C., Herzlieb, S.E., & Kramer, D.L. 2005. Diel activity changes in female yellowtail damselfish (Microspathodon chrysurus): Implications for a tradeoff between reproduction and cleaning. Marine Ecology Progress Series. 296: 1-11. (Feature article).
Sikkel, P.C. and Kramer, D.L. 2006. Territory revisits reduce intrusion during spawning trips by female yellowtail damselfish Animal Behaviour. 71: 71-78
2) The ecological and evolutionary relationship between hosts, parasites, and cleaners; the spatiotemporal variation in host-parasite interaction, and the ecology of parasitic isopods.
Research sites: Bellairs Research Institute, Barbados; Isla Magueyes Marine Laboratory, Puerto Rico and Culebra, Puerto Rico; MacLean Marine Science Center, University of the Virgin Islands, St. Thomas; Virgin Islands Environmental Resource Station, St. John; Guana Island, BVI; Silliman University Marine Laboratory, Philippines; and Lizard Island, Australia.
Collaborators: I.M. Côté, K.L. Cheney, W. Hunte, D.L. Kramer, C. Fuller, D. Nemeth, A. McCammon, E.H. Williams, R. Ziemba, A. Grutter, N. Smit, R. Abesamis, and R. Welicky. Sample publications: Sikkel, P.C., Fuller, C.A.and Hunte, W. 2000. Habitat/sex differences in time at cleaning stations and ectoparasite loads in a Caribbean reef fish. Marine Ecology Progress Series 193: 191-99.
Sikkel, P.C., Cheney, K.L and Côté, I.M. 2004. In situ evidence for ectoparasites as a proximate cause of cleaning interactions in marine reef fish. Animal Behaviour 68: 241-247.
Sikkel, P.C., Herzlieb, S.E., & Kramer, D.L. 2005. Diel activity changes in female yellowtail damselfish (Microspathodon chrysurus): Implications for a tradeoff between reproduction and cleaning. Marine Ecology Progress Series. 296: 1-11. (Feature article).
Sikkel, P.C., Schaumburg, C, Mathenia, J. 2006. Diel infestation patterns of gnathiid isopod larvae on Caribbean reef fishes. Coral Reefs. 25: 683-689.
Sikkel, P.C., Nemeth, D., McCammon, A, and Williams, E.H. 2009 Habitat/species differences in monogenean loads of free-living sympatric surgeonfishes (Acanthuridae) in the Virgin Islands.Journal of Parasitology 95(1):63-68
Sikkel, P.C., Ziemba, R.E., Sears, W. and Wheeler, J. 2009. Ontogenetic shifts in timing of host infestation by parasitic gnathiid isopod larvae on Caribbean coral reefs. Coral Reefs 28:489-495.
McCammon, A., Sikkel, P.C., Nemeth. D. 2010. Effects of three Caribbean cleaner shrimps on ectoparasitic monogeneans in a semi-natural environment. Coral Reefs 29: 419-426.
Welicky, R., Sikkel, P.C. 2014. Prevalence of the cymothoid parasite Anilorca haemuli on its French grunt host in the eastern Caribbean. Marine and Freshwater Research 65: 1018-1026. Feature Article
Welicky, R., Sikkel, P.C. 2015. Decreased movement related to parasite infection in a diel migratory coral reef fish. Behavioral Ecology and Sociobiology. 69: 1437-1446.
Artim, J., Sellers, J., Sikkel, P.C. 2015. Micropredation by gnathiid isopods on settlement-stage larval reef fish in the Eastern Caribbean Sea. Bulletin of Marine Science. 91: 479-487. Feature Article
Artim, J., Sikkel, P.C. 2016. Comparison of sampling methodologies and estimation of population parameters for a temporary fish ectoparasite. International Journal for Parasitology: Parasites and Wildlife 5: 145-157.
Sikkel, P.C., Welicky, R., Artim, J., McCammon, A., Sellers, J, Jenkins, W., Coile, A. (in press). Nocturnal migration reduces exposure to micropredation in a coral reef fish. Bulletin of Marine Science.
3) The role of parasites in trophic dynamics of coral reefs and surrounding habitats:
Study sites: St. John, US Virgin Islands and Puerto Rico.
Collaborators: A. Demopoulos, R. Welicky, D. ParkynSample publications: Demopoulus, A., Sikkel, P.C. 2015. Enhanced understanding of ectoparasite-host trophic linkages on coral reefs through stable isotope analysis. International Journal of Parasitology: Parasites and Wildlife Welicky, R., Demopoulos, A. Sikkel, P.C. (in press). Stable carbon and nitrogen isotope analyses reveal resource use differences associated with Anilocra spp. parasitism in two coral reef fishes. Marine Ecology.
4) The role of parasites in species invasions and effects of invasive species on host-parasite dynamics.
Work in this area is currently focused on an inter-ocean comparison of parasites of red lionfish (Pterois volitans) that has invaded the Caribbean from its native tropical Pacific.
Study sites: Lee Stocking Island, Bahamas, Little Cayman Island, University of Guam Marine Laboratory, Silliman University, Philippines, University of the Virgin Islands, US Virgin Islands.
Collaborators: M. Hixon, A. Dove, J. McIlwain, K. Cure, M. Albins, L. Tuttle, Z. Ramos-Ascherl, E. Williams, L. Bunkley Williams. Sample publications: Sikkel, P.C., Tuttle, L. Cure, K., Coile, A., Hixon, M. 2014. Low susceptibility of invasive red lionfish (Pterois volitans) to a generalist ectoparasite. PLOS One 9(5): e95854. Ascherl, Z., Williams, E., Williams, L., Tuttle, L., Sikkel, P.C., Hixon, M. 2015. Parasitism in Pterois volitans (Scorpaenidae) from coastal waters from Puerto Rico, the Cayman Islands and the Bahamas. Journal of Parasitology 101: 50-56. Demopoulus, A., Sikkel, P.C. 2015. Enhanced understanding of ectoparasite-host trophic linkages on coral reefs through stable isotope analysis. International Journal of Parasitology: Parasites and Wildlife.
5) Blood parasites of coral fishes.
This project focuses on characterizing blood parasite communities in coral reef fishes, their transmission dynamics, and their effects on hosts.
Study sites: Eastern Caribbean, Philippines
Collaborators: N. Smit, A. Davies, C. Cook, A. Campbell, J. RobinsonSample publications: Cook, C., Sikkel, P.C., Renoux, L., Smit, N. 2015. Blood parasite biodiversity of reef-associated fishes of the eastern Caribbean. Marine Ecology Progress Series 533: 1-13. Feature Article
Gnathiid Gnation 