Gw. Hosie et al., Macrozooplankton community structure off East Antarctica (80-150 degrees E) during the Austral summer of 1995/1996, DEEP-SEA II, 47(12-13), 2000, pp. 2437-2463
Citations number
49
Categorie Soggetti
Aquatic Sciences","Earth Sciences
Journal title
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
Zooplankton data from routine 0-200 m oblique trawls and targeted trawls we
re analysed using cluster analysis and non-metric multidimensional scaling
to define the communities in Eastern Antarctica (80-150 degrees E), their d
istribution patterns, indicator species, and species affinities. Three comm
unities were defined based on routine trawls. The Main Oceanic Community co
mprising herbivorous copepods, chaetognaths, and the euphausiid Thysanoessa
macrura dominated the area west of 120 degrees E. The area east of 120 deg
rees E was dominated by Salpa thompsoni. The third community located in the
neritic zone was dominated by Euphausia crystallorophias. Antarctic krill
Euphausia superba did not form a distinct community in its own right, unlik
e previous observations in Prydz Bay. Krill were distributed throughout mos
t of the survey area but generally in higher abundances towards the shelf b
reak. Overall, krill abundance was low compared with previous net surveys i
n Prydz Bay. Three main types of assemblages were identified based on targe
t trawls. The first group was dominated by krill (mean 1149 individuals per
1000 m(3)) which represented > 99% of Group 1 catches in terms of numbers
and biomass. Group 2 comprised the bulk of target trawls and comprised a wi
de diversity of species typical of the main oceanic community, with a mean
abundance approximately half of that observed in the routine trawls. The th
ird group comprised trawls in the neritic zone dominated by E. crystallorop
hias. No salp-dominated aggregation was found. While E. superba did not dom
inate a distinct community geographically as seen in previous Prydz Bay sur
veys, it did dominate discrete layers or aggregations, showing that both ho
rizontal and vertical separation of communities exist. (C) 2000 Elsevier Sc
ience Ltd. All rights reserved.