Interspecific variation in potential importance of planktivorous damselfishes as predators of Acanthaster sp. eggs
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Coral-eating crown-of-thorns starfish (Acanthaster sp.) often exhibit dramatic population outbreaks, suggesting that their local abundance may be relatively unchecked by predators. This may be due to high concentrations of anti-predator chemicals (saponins and plancitoxins), but the effectiveness of chemical deterrents in protecting Acanthaster sp., especially spawned eggs, from predation remains controversial. We show that planktivorous damselfishes will readily consume food pellets with low proportions (≤80%) of eggs of crown-of-thorns starfish. However, all fishes exhibited increasing rejection of food pellets with higher proportions of starfish eggs, suggesting that chemicals in eggs of crown-of-thorns starfish do deter potential predators. Interestingly, palatability thresholds varied greatly among the nine species of planktivorous fish tested. Most notably, Amblyglyphidodon curacao consumed food pellets comprising 100% starfish eggs 1.5 times more than any other fish species, and appeared largely insensitive to increases in the concentration of starfish eggs. After standardising for size, smaller fish species consumed a disproportionate amount of pellets comprising high proportions of starfish eggs, indicating that abundant small-bodied fishes could be particularly important in regulating larval abundance and settlement success of crown-of-thorns starfish. Collectively, this study shows that reef fishes vary in their tolerance to anti-predator chemicals in crown-of-thorns starfish and may represent important predators on early life-history stages.
KeywordsAcanthaster Chemical defence Coral reefs Predation Saponins
This project was funded by an Ian Potter Foundation 50th Anniversary Commemorative Grant awarded to ZLC by the Australian Museum Lizard Island Research Station, in addition to a research allocation supplied by the ARC Centre of Excellence for Coral Reef Studies. We would like to thank Jordi Boada Garcia, Vanessa Messmer, Ben Mos and Molly Scott for field and laboratory assistance. Research was conducted in accordance with the James Cook University animal ethics guidelines. Fish were collected under Great Barrier Reef Marine Park Authority Permit Number G13/35909.1.
- Anderson M, Gorley RN, Clarke RK (2008) PERMANOVA + for PRIMER: Guide to software and statistical methods. PRIMER-E, PlymouthGoogle Scholar
- Birkeland CE, Lucas JS (1990) Acanthaster planci: major management problem of coral reefs. CRC Press, Boca Raton, FLGoogle Scholar
- Conand C (1984) Distribution, reproductive cycle and morphometric relationships of Acanthaster planci (Echinodermata: Asteroidea) in New Caledonia, western tropical Pacific. Proceedings of the 5th International Echinoderm Conference, Galway, Ireland, pp 499–506Google Scholar
- Endean R (1969) Report on investigations made into aspects of the current Acanthaster planci (crown of thorns) infestations of certain reefs of the Great Barrier Reef. Queensland Department of Primary Industries (Fisheries Branch), Brisbane, AustraliaGoogle Scholar
- Endean R (1977) Acanthaster planci infestations of reefs of the Great Barrier Reef. Proc 6th Int Coral Reef Symp 1:185–191Google Scholar
- Hamner WM, Jones MS, Carleton JH, Hauri IR, Williams DM (1988) Zooplankton, planktivorous fish, and water currents on a windward reef face: Great Barrier Reef, Australia. Bull Mar Sci 42:459–479Google Scholar
- Lucas JS (1975) Environmental influences on the early development of Acanthaster planci (L). Crown-of-thorns starfish seminar proceedings, Australian Government Publishing Service, Canberra, pp 109–121Google Scholar
- Pearson RG, Endean R (1969) A preliminary study of the coral predator Acanthaster planci (L.) on the Great Barrier Reef. Fisheries Notes 3:27–55Google Scholar
- Rivera-Posada J, Caballes CF, Pratchett MS (2014) Size-related variation in arm damage frequency in the crown-of-thorns sea star, Acanthaster planci. Journal of Coastal Life Medicine 2:187–195Google Scholar
- Sweatman HPA, Cheal AJ, Coleman GJ, Fitzpatrick BM, Miller IR, Ninio R, Osborne K, Page CM, Ryan DAJ, Thompson AA, Tomkins P (2000) Long-term monitoring of the Great Barrier Reef. Status report 4. Australian Institute of Marine Science, Townsville, p 117Google Scholar
- Yamaguchi M (1974) Larval life span of the coral reef asteroid Gomophia egyptiaca Gray. Micronesica 10:57–64Google Scholar