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Discovery of gregarine parasitism in some Southern Ocean krill (Euphausiacea) and the salp Salpa thompsoni


Wallis, JR and Smith, AJR and Kawaguchi, S, Discovery of gregarine parasitism in some Southern Ocean krill (Euphausiacea) and the salp Salpa thompsoni, Polar Biology, 40, (9) pp. 1913-1917. ISSN 0722-4060 (2017) [Refereed Article]

Copyright Statement

Copyright 2017 Springer-Verlag Berlin Heidelberg

DOI: doi:10.1007/s00300-017-2089-0


The presence and role of endoparasites in pelagic macrozooplankton within the Southern Ocean are poorly understood. Accounts of such parasites are generally restricted to the Antarctic krill species Euphausia superba, with little information on other possible host species. Endoparasitic gregarines were recorded for the first time in the euphausiids Euphausia triacantha and Euphausia valentini and the salp Salpa thompsoni during the Kerguelen Axis Antarctic research cruise (February–March 2016). Gregarines found in E. triacantha and E. valentini were morphologically similar to those previously identified in Antarctic krill, E. superba. Despite overlapping distributions, the smaller euphausiid Thysanoessa macrura possessed a different gregarine endoparasite, indicating parasite–host specificity in Southern Ocean euphausiids. Most notable was the discovery of large gregarines in the stomachs of aggregate individuals of S. thompsoni. The presence of gregarines in these dominant macrozooplankton indicates that endoparasitism within the Southern Ocean is more common than previously thought. Gregarines were observed in guts of krill and salps collected between 57.9 and 63.6°S. The continual presence of gregarines in the species examined indicates that these host-parasite interactions are not isolated events with differing life stages of gregarines within the same intestinal tract of some species indicating periodic infection. The impacts of gregarine parasitism on these newly identified hosts are unclear and require further investigation to understand the spatial and temporal patterns of gregarine-host interactions.

Item Details

Item Type:Refereed Article
Keywords:krill, Southern Ocean, reproductive biology, Thysanoessa macrura, Euphausia triacantha, Euphausia valentini, Indian Ocean
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Biological oceanography
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Antarctic and Southern Ocean oceanic processes
UTAS Author:Wallis, JR (Dr Jake Wallis)
UTAS Author:Smith, AJR (Ms Abigail Smith)
UTAS Author:Kawaguchi, S (Dr So Kawaguchi)
ID Code:123581
Year Published:2017
Web of Science® Times Cited:3
Deposited By:Ecology and Biodiversity
Deposited On:2018-01-11
Last Modified:2018-05-30

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