| Summary: | Progress Code: completed Statement: This voyage is one of six which studied the abundance and disribution of Euphausia superba. This provided a good coverage of the area at varying season times and conditions. There are some differences in sampling sites due to logistical constraints and weather conditions. Data collection: A Rectangular Midwater Trawl (RMT 1+8) was used for the collection of larval and post larval (juvenile and adult) krill Euphausia superba, and other zooplankton. Three haul methods were used. At each station a shallow downward oblique haul was taken from the surface to 200m. At selected stations a deep downward oblique haul from 200m to 1000m was taken to collect early developmental stages of Euphausia superba. When krill swarms were located at particular depths (by a Simrad EK 120 echosounder), specific aimed horizontal tows were made. On-ship processing: This included removing specimens of Euphausia superba and other large and fragile zooplankton from the catch. All specimens were preserved in Steedman's solution until examination at the Antarctic Division laboratories. Krill swarm catches were weighed using a spring balance, and part of the catch (greater than 200 specimens) were preserved in Steedman's solution. Post-ship processing: This included classification of the RMT 8 post-larval krill into juvenile, male and female maturation stages, using the Makarov and Denys (1981) system. The body length (using a slide caliper) and body wet weight (using an electronic top-pan balance) were measured for each RMT 8 specimen. Non-krill zooplankton in the RMT 8 samples were identified, weighed and counted. The RMT 1 catches were sorted to separate the Euphausia superba larvae and other euphausiid species larvae from the remaining zooplankton. The euphausiid larvae were classified into developmental stages and counted under a dissecting microscope. Data are logically consistent, as oceanographic data (CTD measurements) and water collections for phytoplankton pigment analysis were also obtained at ...
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