This dataset contains estimates of krill swarm characteristics from statistical models based on underway acoustic observations along with underway and remote-sensed environmental data. Estimates of internal swarm density and depth across the study region (60-80 degrees E) are included for the time of the survey (Feb 2006). Estimates of February internal swarm density across the broader East Antarctic region (30-120 degrees E) are also included for the period 2001-2010.

Metadata record for data from ASAC Project 1117 See the link below for public details on this project. ---- Public Summary from Project ---- The aim of this project is to determine how feasible it is to regularly sample the pelagic under-ice community during winter at a coastal site near Mawson. Very few attempts have been made to sample the water column under the ice during the winter months and the processes that occur during this period remain critical gaps in our knowledge of the Antarctic marine ecosystem. ------------------------------------- The pelagic community under the Mawson sea ice was sampled during the winter of 2001 using 'light trap' sampling devices. The 'light traps' were tested at various depths in a range of configurations to determine whether they were an appropriate instrument to sample the winter pelagic community under the ice. Fourteen successful deployments of the light traps were made on seven separate occasions from 12 June to 12 September 2001. The light traps were deployed at three different depths - the underside of the sea ice, mid water, and just above the sea floor. Two different light sources were used to attract the animals, namely fluorescent tubes and cyalume sticks. Two different configurations of the traps were tested to retain the animals inside the trap - one with plastic flaps to trap the animals, the other with no flaps, allowing the animals to move freely inside the trap. The light traps were deployed and retrieved during darkness to avoid any influence of ambient light. The objectives of the project were met and it is assessed that the pelagic community in winter can be effectively sampled using this methodology. A result of particular interest is the success of the traps in capturing Pleuragramma antarctica, a species which has proven difficult to capture using traditional sampling methods such as nets.

Krill Ecology - Technical Reports and Systems Guides A series of documents detailing work completed and methods used at the Krill Aquarium located at the Australian Antarctic Division. Technical Report # Title and Author Technical Report 1. 26th January 1994. DAPI Epiflourescence Technique. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 2. 5th March 1995. Bag Culture - Cell Growth Count Protocol. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 3. 12th January 1996. Chemical 'Spiking' of Krill Aquarium Bio-filter T12. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 4. 24th June 1996. Cold Temperature Algal Bag Culture Methodology. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 5. 16th April 1997. Algal Bag Culture - Harvesting Method. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 6. 26th October 1999. Aquarium System Bulk Seawater Collection and Storage. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 7. 11th October 1999. Sodium Hypochlorite Treatment of Algal Bag Culture Filtration Unit. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 8. 18th October 1999. Feeding Krill - Algal Strains, Feeding Rate and Nutritional Values. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 9. 22nd November 1999. Krill Biology Section - Parental Algal Culture Maintenance. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 10. 10th April 2000. Krill Group Databases and Maintaining Daily Data Records. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 11. 11th May 2000. Making Up and Use of Iodine Solution as an Indicator of the Presence of Chlorine in Freshwater. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 12. 1st June 2000. Testing for Harmful Ammonia (NH3) in Aquarium Sea Water. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 13. 12th June 2000. Digitron Digilog 2088T Digital Temperature Logger/Gauge - Operating Instructions and Down-Loading Logged Data Guide. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 14. 27th June 2000. Krill Biology - Marine Science Support Shed Gear Storage. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 15. 15th October 2000. Making up of fe Growth Media Stock Solutions for Parental and Algal Bag Culture Production. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 16. 15th January 2001. Algal Bag Culture - Growth Rate Analysis. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 17. 19th July 2004. Protective Epoxy Coating of Onga Seawater Collection Fire Pump. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 18. 27th October 2004. New Krill Aquarium - Bulk Seawater Collection and Storage Logistics. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 19. 11th March 2005. New Krill Aquarium - Algal Bag Culture Filtration System. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 20. 6th April 2005. New Culture Cabinet Bag to Bag Inoculation Procedure. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 21. 17th June 2005. Agar Bacterial Plate Testing for Krill Algal Culture Stocks. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 22. 29th July 2004. New Algal Culture Cabinet - Bag Culture Setup Methodology. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 23. 24th May 2005. Protocol for Sterilization of Bag Culture Air Supply System. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 24. 30th May 2005. 200 litre tank Algal Batch Culture Setup. Author: P. M. Cramp. Australian Antarctic Division. Technical Report 25. 22nd June 2005. Making Up and Shaping Plastic Bags for Algal Culture. Author: P. M. Cramp. Australian Antarctic Division. Techincal Report 26. 19th December 2005. New Krill Aquarium - Algal Strains, Feeding Rates and Nutritional Values. Author: P. M. Cramp. Australian Antarctic Division.

Metadata record for data from ASAC Project 587 See the link below for public details on this project. From the abstracts of some of the referenced papers: The concentration of fluoride in the body parts of a range of Antarctic crustaceans from a variety of habits was examined with the aim of determining whether fluoride concentration is related to lifestyle or phylogenetic grouping. Euphausiids had the highest overall fluoride concentrations of a range of Antarctic marine crustaceans examined; levels of up to 5477 micro grams per gram were found in the exoskeleton of Euphausia crystallorophias. Copepods had the lowest fluoride levels (0.87 micrograms per gram) whole-body); some amphipods and mysids also exhibited relatively high fluoride levels. There was no apparent relationship between the lifestyle of the crustaceans and their fluoride level; benthic and pelagic species exhibited both high and low fluoride levels. Fluoride was concentrated in the exoskeleton, but not evenly distributed through it; the exoskeleton of the head carapace and abdomen contained the highest concentrations of fluoride, followed by the feeding basket and pleopods, and the eyes. The mouthparts of E. superba contained almost 13,000 microgams F per gram dry weight. Antarctic krill tail muscle had low levels of fluoride. After long-term (1 to 5 year) storage in formalin, fluoride was almost completely lost from whole euphausiids. A series of experiments was carried out to determine the relationship between feeding, moulting, and fluoride content in Antarctic krill (Euphausia superba). Starvation increased the intermoult period in krill, but had no effect on the fluoride concentrations of the moults produced. Addition of excess fluoride to the sea water had no direct effect on the intermoult period, the moult weight, or moult size. Additions of 6 micrograms per litre and 10 micrograms per litre fluoride raised the fluoride concentrations of the molts produced and of the whole animals. The whole body fluoride content varied cyclically during the moult cycle, reaching a peak 6 days following ecdysis. Fluoride loss at ecydsis could largely be explained by the amount of this ion shed in the moult. This work was completed as part of ASAC projects 41 and 587 (ASAC_41, ASAC_587).

A collection of scanned logs and documentation from the BROKE cruise of the Aurora Australis in the 1995/1996 season. Available logs include: BROKE V4 1995/1996 Catch Composition - 2 Logs BROKE V4 1995/1996 Krill Larvae Log BROKE V4 1995/1996 Krill Morphometrics - 3 logs BROKE V4 1995/1996 Trawl Log BROKE V4 1995/1996 Wet Lab Log See the logs for further details.

Instantaneous growth rates (IGR) of Antarctic krill kept under experimental conditions were measured. The measured appendages included the uropods, telson (both standard length measurements with the IGR technique) and the pleopod endopodite and pleopod exopodite were investigated as an alternate length measurement. IGR measurements were recorded on 90 experimental animals. The total carbon content of 45 krill of various size ranges (collected directly from the field) was determined. The relationship between the change in length in carbon as a function of growth was investigated. The parameters measured were total length, mean uropod length, telson length, wet weight, dry weight and total carbon content. This dataset was collected as part of ASAC project 141. See metadata record ASAC_141 - Collection of live Antarctic krill 'Euphausia superba'. The fields in this dataset are: Krill Total length (mm) Telson length (mm) Mean uropod length (mm) Wet weight (g) Dry weight (g) Dry Weight (mg) Carbon content as a % of dry weight Total carbon content (g) Moult Sex

Regular Trawl At each regular trawl station a quantitative standard double oblique tow was conducted from the surface down to 200 m (or to within 10 m of the bottom at stations shallower than 200 m). Such a depth range is considered to be the best compromise between the time available for sampling and the likely vertical depth range of krill. During the hauls, ship speed was maintained at a constant 2.5 plus or minus 0.5 knots. Wire speed of 0.7 to 0.8 m/s during paying out and of 0.3 m/sec during hauling (approx. 0.5 m/s and 0.2 m/s respectively at vertical depth change rate). The net mouth angle is remarkably constant during hauling within the speed ranges given above. When the net reaches maximum depth, the winch was stopped for about 30 seconds to allow the net to stabilise before starting retrieval. When hauling, propeller thrust was turned off when the net reached a depth of 15 to 20 m; this was to minimise the effects of the propeller action on the net operation and avoids damage of the samples. Target Trawl Whenever interesting targets were seen on the echo-sounder, or large amounts of krill were required for any purpose, target trawls were performed. Once the position of the target was marked, the ship was turned and navigated to run over the target from direction required within navigation capacity. The ship speed was lowered down to below 2.0 knots before hitting the target, so that the net could be lowered down to the desired depth whenever the net reached the target. Fine adjustments were made throughout the trawl by monitoring the echo-sounder in the aft control room. For live krill target trawl, ship speed was kept as slow as possible to avoid any damage to krill. Sample processing for all regular trawl stations: RMT-8 1.Measure the total sample volume (Drain water, then measure using water replacement; mandatory only for the regular hauls) 2.Sort out all Antarctic krill and count their number. If the sample mainly consists of krill and the volume is more than ~1L, a known portion of the whole sample was sub-sampled for the further processing. 3.Stage (TL, Carapace Length, Maturity) of all krill (or subsample), up to 50 to 150 individuals, and digestive gland size (the longest axis) of up to 50 individuals were measured using digital calipers. 4.Other zooplankton groups were immediately sorted out from the catch and their numbers were recorded. Preservation of RMT-8 samples Krill (including those used for onboard demography measurements) were fixed in 10% formalin for their further analysis. Whenever excess amount of krill catch were made, they were sampled and frozen for POP (persistent organic pollutant) measurements, preserved in 80% ethanol for genetic analysis, and frozen under -80C/ liquid nitrogen for chemical analysis. Fish were preserved in formalin, EtOH, or frozen. Squids were preserved in ethanol. RMT-1 1.The whole sample was fixed with 10 % formalin. 2.If the sample volume was too large, then a known proportion of catch was randomly sub-sampled and fixed. This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679).

Metadata record for data from ASAC Project 2337 See the link below for public details on this project. ---- Public Summary from Project ---- The experimental krill research program is focused on obtaining life history information of use in managing the krill fishery - the largest Antarctic fishery. In particular, the program will concentrate on studies into schooling, growth and ageing of krill. From the abstracts of some of the referenced papers: Nucleic acid contents of tissue were determined from field-caught Antarctic krill to determine whether they could be used as an alternative estimator of individual growth rates which can currently only be obtained by labour intensive on-board incubations. Krill from contrasting growth regimes from early and late summer exhibited differences in RNA-based indices. There was a significant correlation between the independently measured individual growth rates and the RNA-based indices. There was a significant correlation between the independently measured individual growth rates and the RNA:DNA ratio and also the RNA concentration of krill tissue, although the strength of the relationship was only modest. DNA concentration, on average, was relatively constant, irrespective of the growth rates. The moult stage did not appear to have a significant effect on the nucleic acid contents of tissue. Overall, the amount of both nucleic acids varied considerably between individuals. Nucleic acid-based indicators may provide information concerning the recent growth and nutritional status of krill and further experimentation under controlled conditions is warranted. The are, however, reasonably costly and time-consuming measurements. Growth rates of Antarctic krill Euphausia superba Dana in the Indian Ocean sector of the Southern Ocean were measured in 4 summers. Growth rate was measured using an 'instantaneous growth rate' technique which involved measuring the mean change in length if the uropods at moulting. In the first 4 days following collection mean growth rates ranged from 0.35 to 7.34% per moult in adults and 2.42 to 9.05% in juveniles. Mean growth rates of adult and juvenile krill differed between areas and between the different years of the investigation. When food was restricted under experimental conditions, individual krill began to shrink immediately and mean population growth rates decreased gradually, becoming negative after as little as 7 days. Populations of krill which exhibited initial growth rates began to shrink later than those which had initially been growing more slowly. Data were collected on growth rates of krill. These data were collected as part of ASAC projects 34, 1074, 2220 and 2337. ASAC_34 - Ecophysiology of Antarctic Krill 'Euphausia superba' ASAC_1074 - Seasonal growth in krill ASAC_2220 - Collection of live Antarctic krill ASAC_2337 - Experimental studies into growth and ageing of krill The fields in this dataset are: Field season (eg FS9596 = Field Season 1995-1996) Area (eg Indian Ocean) Cruise Month Date Latitude Longitude Total Number of Krill Dead Krill Moulted Krill Experiment ID Station ID Sample ID Sex Growth (IGR%) (% growth at time of moulting) Uropod Size (mm) Days after capture (when moulted) Standard length