MEPS 351:273-286 (2007)  -  DOI: https://doi.org/10.3354/meps07119

Effects of annual changes in primary productivity and ocean indices on breeding performance of tropical roseate terns in the western Indian Ocean

David Monticelli1,2,*, Jaime A. Ramos3, Graham D. Quartly4

1Royal Belgian Institute of Natural Sciences, Section of Conservation Biology, 29 Rue Vautier, 1000 Brussels, Belgium
2Laboratory of Tropical and Subtropical Forestry, Unit of Forest and Nature Management, Gembloux Agricultural University, 2 Passage des Déportés, 5030 Gembloux, Belgium
3Institute of Marine Research (IMAR), Department of Zoology, University of Coimbra, 3004-517 Coimbra, Portugal
4National Oceanography Centre, Southampton (NOCS), Empress Dock, Southampton, Hampshire SO14 3ZH, UK

ABSTRACT: We assessed the influence of inter-annual changes in primary productivity and local, regional and large scale ocean indices on the breeding parameters of roseate terns Sterna dougallii on Aride Island, Seychelles, western Indian Ocean. Productivity (chicks per breeding pair), timing of breeding and clutch and egg sizes were monitored annually for 8 yr and correlated with local ocean productivity (denoted by Sea-viewing Wide Field-of-view Sensor, SeaWiFS, estimates of chlorophyll concentration, CC), sea surface temperature and indices recording the status of the Indian Ocean Dipole and of El Niño. The rate of increase in CC between mean laying date and CC peak value was positively related to roseate tern productivity and mean clutch size over the 1998 to 2005 study period. Colony productivity seemed also to be influenced by the Multivariate El Niño Index. In most years, the breeding phenology of roseate terns corresponded to the local increase in CC around Aride, and failure to adjust timing of reproduction to the timing of the phytopankton bloom decreased the probability of breeding success. This is the first study showing that a tropical seabird species is sensitive to inter-annual variations in the intensity and timing of the phytoplankton bloom, which should be connected to annual variations in the availability of its main fish prey (juvenile goatfishes). Overall, these patterns indicate that the reproduction of this top marine predator is dictated by the temporal variability in oceanographic conditions. We suggest that CC data available over the world’s oceans may be a useful tool to develop models predicting the fate of colonies of inshore feeding seabirds when other, more conventional, monitoring methods cannot be used.


KEY WORDS: Sterna dougallii · Breeding · Inter-annual variation · Ocean productivity · El Niño · SeaWiFS · Seabird ecology · Indian Ocean


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Cite this article as: Monticelli D, Ramos JA, Quartly GD (2007) Effects of annual changes in primary productivity and ocean indices on breeding performance of tropical roseate terns in the western Indian Ocean. Mar Ecol Prog Ser 351:273-286. https://doi.org/10.3354/meps07119

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