Summary of Abstract Submission

Abstract Submission No. IO50-08-0003PresentationOral


Alicia Sutton*1, Lynnath E Beckley1

1 Murdoch University, Australia


Krill are holo-planktonic crustaceans occupying the ocean basins of the world. The first basin-wide investigation of krill zoogeography was conducted during the first International Indian Ocean Expedition (1962 - 1965). Together with all other available information on krill distribution, spatially-explicit data on species richness and taxonomic distinctness were produced for the 57 krill species occurring in the Indian Ocean. Average taxonomic distinctness is a measure of diversity that can be applied to presence/absence data and is robust to differences in sampling effort, and can include historical data sets. Species richness was highest in the tropics and subtropics, and within the Agulhas and Leeuwin Currents. Most areas of the Indian Ocean were comparable in average taxonomic distinctness, which reflects the high connectivity across the basin and, in turn, the dispersal of holo-planktonic krill. Areas with lower distinctness included the Red Sea and the north-west coast of India, whilst, somewhat surprisingly, areas of higher distinctness were found in the middle of the Bay of Bengal. Although only 10 species were recorded from this region, they were spread across six genera, including Bentheuphausia amblyops, from the monotypic family Bentheuphausiidae. All values of distinctness fell within the 95% probability limits of the expected mean, indicating that the krill species sampled were representative of the Indian Ocean species pool. Environmental factors and ocean climatology have been modelled with krill zoogeography to establish basin-wide relationships across the Indian Ocean.