| Summary: | Progress Code: completed Statement: This data set contains the results from the fifth cruise in a series of six, producing a good coverage of the area at varying times and conditions. Data collection: At each of the twenty three stations, a shallow oblique haul, down to 200m, was made using a rectangular midwater trawl (RMT1+8). When ice conditions permitted, an additional deep oblique haul, from 200m to 1000m, was also made. One specific horizontal tow was made. When ice conditions made it unsafe to haul the RMT1+8 or when the ship was stopped for the night, vertical hauls were made using an ORI-2000 conical net. These hauls were made usually from 1000m, although some hauls ranged between 10 and 2000m. Under-ice diving was also carried out. Krill were collected by hand nets, and behavioural observations were recorded using an underwater video and 16mm cine-camera. The video observation results are published in O' Brien, D.P. (1987) Direct Observations of Euphausia superba and Euphausia crystallorophias under pack-ice during the Antarctic spring of 1985. Journal of Crustacean Biology. 7:437-448. Ship-board processing: Large and fragile zooplankton were sorted from the remainder of the catch, and all specimen were preserved in Steedman's solution. Post-ship processing: Krill were sorted into juvenile, male and female. Body length and weight were measured, using a slide caliper and Mettler top-pan balance respectively. Male and female krill were further separated into maturation stages, according to the Makarov and Denys (1981) system. Non-krill zooplankton from the RMT8 samples were speciated, weighed and counted. The total catches of the RMT1 were wet weighed, and the larvae of the euphausiid species Euphausia frigida and Thysanoessa macrura were extracted, staged and counted under a dissecting microscope. The larvae of other euphausiids Eupahusia superba, Euphausia crystallorophias and Euphausia triacantha were not collected by the RMT1. Consistency can be checked by comparison between different trawl ...
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