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Drivers of Krill zoogeography in the Indian Ocean: the implications of poleward flowing boundary currents

Sutton, A.L. and Beckley, L. (2013) Drivers of Krill zoogeography in the Indian Ocean: the implications of poleward flowing boundary currents. In: AMSA2013 Golden Jubilee Conference, 7 - 11 July, Gold Coast, QLD, Australia.


With 86 species known worldwide, krill (Euphausiaceae) are an important link in marine food webs and are widespread in all oceans. In the Indian Ocean, the first basin-wide investigation of krill zoogeography was conducted during the International Indian Ocean Expedition (1962-65). Many subsequent plankton and micro-nekton studies conducted in the Indian Ocean over the past five decades have been collated in a Geographical Information System to produce distribution maps of the 66 krill species occurring throughout the basin. Species richness was greatest around the tropical and subtropical latitudes, with a decline towards more temperate zones. This latitudinal trend has also been observed for krill in the Pacific Ocean (80 species) and Atlantic Ocean (54 species). Through the availability of satellite imagery and Argo data, trends in krill zoogeography can be correlated with broad-scale environmental factors to establish basin wide relationships. Factors such as sea temperature, chlorophyll a, latitude and depth have been investigated for their potential influence on krill zoogeography. One of the features that makes the Indian Ocean unique is the unusual presence of two poleward flowing boundary currents, the Agulhas Current in the south-west and the Leeuwin Current in the south-east. Investigations into the Leeuwin Current krill community have so far revealed 25 species of which Euphausia recurva, Pseudeuphausia latifrons and Stylocheiron carinatum are numerically dominant. Both boundary currents are responsible for the expatriation of tropical marine species to more southern latitudes, and appear to similarly influence zoogeographical patterns of krill within the Indian Ocean.

Item Type: Conference Item
Murdoch Affiliation(s): School of Veterinary and Life Sciences
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