Metadata record for data from AAS (ASAC) Project 2337. An excel spreadsheet is available for download from the URL given below. The spreadsheet contains three worksheets: a summary of the data validated data all data Public The experimental krill research program is focussed 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, ageing, behaviour and reproduction of krill as well as into the operation, behaviour and trends of the krill fishery. Project objectives: To investigate key aspects of the biology of Antarctic krill and its management utilising the facilities at the Australian Antarctic Division. Taken from the 2008-2009 Progress Report: Progress against objectives: We succeeded to take krill larvae reproduced in-house last year up to adult stage (external maturity) for the first time in our research laboratory (the second facility ever outside Antarctica), which means that last year's larvae reached maturity within a year in our aquarium, compared to 2-3 years in the wild, however spawning from this population is yet to be recorded. We also had successful reproduction this year and currently these animals are at late larval stage. We have now succeeded in reproduction two years in a row and have established the technique. This is a major step forward in closing Antarctic krill's life cycle in our aquarium. This achievement makes us the only research facility outside Antarctica to be able to conduct live krill experiments for the entire life stage and contribute information on biological parameters important for krill management. Taken from the 2009-2010 Progress Report: Progress against objectives: This year for the first time we have succeeded in closing the entire krill life cycle in our research laboratory (the second facility ever outside Antarctica. We also achieved successful reproduction this year and currently these animals are at the late larval stage. We have now succeeded in krill reproduction for three years in a row and have firmly established the technique. This achievement makes us the only research facility outside Antarctica to be able to conduct live krill experiments for the entire life stage and contribute information on biological parameters important for krill management. Taken from the 2010-2011 Progress Report: Public summary of the season progress: Understanding how krill may respond to various environments is the fundamental information to predict the future of krill centric ecosystem under the climate change. The project's current focus is to study impacts of ocean acidification on krill. The AAD aquarium facility for ocean acidification study is continuing to be upgraded to increase its capacity and stability to undertake its experiments at larger scale. Negative impacts of ocean acidification on krill has been investigated and the range of CO2 level fatal to krill embryonic development was broadly identified, and was published for the first time.

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

Crustaceans grow or shrink in size as they moult. Length of discarded moults represent length of animals before their moulting events. Therefore, by measuring length of discarded moult and length of animal after moult, growth increments at the time of moult can be obtained. IGR is defined as the growth increment expressed as a proportion of pre-moult total length (TL). IGR can be converted into daily growth rate for a given value of TL by calculating absolute growth increment and dividing by an estimate of inter-moult period (IMP). The IGR technique depends on the collection of live krill in good condition. Krill were caught with an RMT-8 net and individual freshly caught animals were randomly selected from the catch and immediately transferred to individual jars. They were then maintained onboard and checked regularly for moults for up to 5 days following capture. The experiments were run a flowthrough seawater system which used 250 ml jars with small holes to allow water exchange in a large flow-through tank of seawater maintained at ambient ocean temperature. No additional food was provided. The system allowed experiments with over 4000 krill. Each krill was checked daily after capture to ascertain whether it had moulted. If an animal had moulted, then the animal and its moult were collected and frozen in liquid nitrogen or at -85 degrees C to be measured back ashore. The growth rate will be estimated from the difference in length of the uropod of the moult and that of the whole post-moult krill. This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679).

These data represent the results of the first study to use Earth System Model (ESM) outputs of SST and chlorophyll-a to simulate circumpolar krill growth potential for the recent past (1960-1989) and future climate change scenarios (2070-2099). Growth potential is obtained using an empirically-derived krill growth model (Atkinson et al. 2006, Limnol. Oceanogr.), where growth is modeled as a function of SST and chlorophyll-a. It serves as an approximation of habitat quality, as areas that support high growth rates are assumed to be good habitat (see Murphy et al., 2017, Sci Rep). To increase confidence in the future projections, ESMs were selected and weighted for each season based on their skill at reproducing observation-based krill growth potential for the recent past. First, eleven ESMs which provided SST and chlorophyll-a outputs were obtained from the Coupled Model Inter-comparison Project 5 archive. These included: CanESM2, CMCC-CESM, CNRM-CM5, GFL-ESM2G, GFDL-ESM2M, GISS-E2-H-CC, HadGEM2-CC, IPSL-CM5A-LR, MPI-ESM-MR, MRI-ESM1 and NorESM1-ME. For each ESM, seasonal surface averages of SST and chlorophyll-a were used to calculate growth potential for the historical scenario (1960-1989), which was then bilinearly interpolated on to the same 1°x1° grid. Satellite observation-based datasets for SST and chlorophyll-a were used to calculate observation-based growth potential for the recent past (1997-2010). These comprised seasonal surface averages of SST (from the OISST v2 daily dataset, 1/4⁰ horizontal resolution) and chlorophyll-a (the mean of the SeaWiFS and Johnson et al. (2013) corrected estimate of SeaWiFS daily datasets, 1/12⁰ horizontal resolution). Observation-based growth potential was then bilinearly interpolated onto the same grid as the ESMs. ESM skill for each season was subsequently assessed against observation-based growth potential using a Taylor Diagram. The ESMs were selected and weighted according to their performance to produce a weighted subset (see "ESM_weighting_method.pdf" file). Of the netcdfs provided, "hist_mean_ensemble.nc" represents the unweighted mean of seasonal growth potential, calculated from the initial ensemble of eleven ESMs for the historical scenario. The "hist_mean_subset.nc" file represents the analogous output of the weighted subset. Future projections of seasonal growth potential for Representative Concentration Pathways (RCPs) 4.5 and 8.5 were obtained using the weighted subset for the period of 2070-2099. These projected seasonal surface averages are provided in the "rcp45_mean_subset.nc" and "rcp85_mean_subset.nc" files. RCPs represent standard climate change scenarios developed by the Intergovernmental Panel on Climate Change, with 4.5 reflecting some mitigation of carbon emissions, and 8.5 being the "business as usual" scenario. Analogous netcdfs for the weighted subset outputs of chlorophyll-a (chl) and SST (tos) for the historical and RCP scenarios are also provided in the "chl_tos_netcdfs.zip" file so that the driving environmental variables underlying growth potential can be examined.

We checked each site by taking ice cores and observing the algae biomass to determine the likelihood of krill living under the sea ice in each location. We also used a Remotely Operated Vehicle (ROV) with cameras attached to observe the abundance of krill under the sea ice. If krill were present we used on the sea ice floe a zooplankton pump, called MASMA, according to Meyer et al. 2009, whereas at the edge of the floe column a custom-built fish pump system was used to collect krill near the surface. The Aqualife Biostream BP40 fish pump was capable of pumping up to 1300 litres per minute without harming animals that pass through the pump. For much of the voyage it was operated from the ctd room and at this increased suction head it ran at about 500 litres per minute. Krill were caught at ice stations 2, 6, 7 and 8. The Krill Sample-Overview.xls file contains information regarding how many krill were caught at each ice stations, who was involved and related information. The SIPEX II Krill Voyage Report.docx contains information about the various issues that were encountered during the voyage. It also contains information from the Bottom Krill experiment, which has its own dataset and metadata record. It is duplicated in both datasets. The larvae were used for a growth experiment using the IGR method and after length measurements frozen for carbon, nitrogen, lipids, stomach and gut content analysis. The total and carapace length were determined of juveniles as well as their digestive gland size. Animals were than dissected and tissues frozen at -80C for further analysis (see above). These condition parameters will be discussed in relation to physical and biological environmental parameters of the ice floe (e.g. sea ice thickness, snow coverage, under ice topography and biomass). When this data is analysed, the dataset will be updated to include analysed versions of the data listed in the Krill Sample-Overview.xls file. Also included in the dataset are technical documents and manuals pertaining to the fish pump that was used. Meyer B et al. 2009. Limnol Oceanogr 54:1595-1614

This model was produced as part of Australian Antarctic Science project 4037 - Experimental krill biology: Response of krill to environmental change - The experimental krill research project is designed to focus on obtaining life history information of use in managing the krill fishery - the largest Antarctic fishery. In particular, the project will concentrate on studies into impacts of climate change on key aspects of krill biology and ecology. This metadata record is to reference the paper that describes the model. There is no archived data output from this data product. Taken from the abstract of the referenced paper: Estimates of productivity of Antarctic krill, Euphausia superba, are dependent on accurate models of growth and reproduction. Incorrect growth models, specifically those giving unrealistically high production, could lead to over-exploitation of the krill population if those models are used in setting catch limits. Here we review available approaches to modelling productivity and note that existing models do not account for the interactions between growth and reproduction and variable environmental conditions. We develop a new energetics moult-cycle (EMC) model which combines energetics and the constraints on growth of the moult-cycle. This model flexibly accounts for regional, inter- and intra-annual variation in temperature, food supply, and day length. The EMC model provides results consistent with the general expectations for krill growth in length and mass, including having thin krill, as well as providing insights into the effects that increasing temperature may have on growth and reproduction. We recommend that this new model be incorporated into assessments of catch limits for Antarctic krill.

The embryonic development of Antarctic krill (Euphausia superba) is sensitive to elevated seawater CO2 levels. This data set provides the experimental data and WinBUGS code used to estimate hatch rates under experimental CO2 manipulation, as described by Kawaguchi et al. (2013). Kawaguchi S, Ishida A, King R, Raymond B, Waller N, Constable A, Nicol S, Wakita M, Ishimatsu A (2013) Risk maps for Antarctic krill under projected Southern Ocean acidification. Nature Climate Change (in press) Circumpolar pCO2 projection. To estimate oceanic pCO2 under the future CO2 elevated condition, we computed oceanic pCO2 using a three-dimensional ocean carbon cycle model developed for the Ocean Carbon-Cycle Model Intercomparison Project (2,3) and the projected atmospheric CO2 concentrations. The model used, referred to as the Institute for Global Change Research model in the Ocean Carbon-Cycle Model Intercomparison Project, was developed on the basis of that used in ref. 4 for the study of vertical fluxes of particulate organic matter and calcite. It is an offline carbon cycle model using physical variables such as advection and diffusion that are given by the general circulation model. The model was forced by the following four atmospheric CO2 emission scenarios and their extensions to year 2300. RCP8.5: high emission without any specific climate mitigation target; RCP6.0: medium-high emission; RCP 4.5: medium-low emission; and RCP 3.0-PD: low emission (1). Simulated perturbations in dissolved inorganic carbon relative to 1994 (the Global Ocean Data Analysis Project (GLODAP) reference year) were added to the modern dissolved inorganic carbon data in the GLODAP dataset (5). To estimate oceanic pCO2, temperature and salinity from the World Ocean Atlas data set (6) and alkalinity from the GLODAP data set were assumed to be constant. Marine ecosystems of the Southern Ocean are particularly vulnerable to ocean acidification. Antarctic krill (Euphausia superba; hereafter krill) is the key pelagic species of the region and its largest fishery resource. There is therefore concern about the combined effects of climate change, ocean acidification and an expanding fishery on krill and ultimately, their dependent predators—whales, seals and penguins. However, little is known about the sensitivity of krill to ocean acidification. Juvenile and adult krill are already exposed to variable seawater carbonate chemistry because they occupy a range of habitats and migrate both vertically and horizontally on a daily and seasonal basis. Moreover, krill eggs sink from the surface to hatch at 700–1,000m, where the carbon dioxide partial pressure (pCO2 ) in sea water is already greater than it is in the atmosphere. Krill eggs sink passively and so cannot avoid these conditions. Here we describe the sensitivity of krill egg hatch rates to increased CO2, and present a circumpolar risk map of krill hatching success under projected pCO2 levels. We find that important krill habitats of the Weddell Sea and the Haakon VII Sea to the east are likely to become high-risk areas for krill recruitment within a century. Furthermore, unless CO2 emissions are mitigated, the Southern Ocean krill population could collapse by 2300 with dire consequences for the entire ecosystem. The risk_maps folder contains the modelled risk maps for each of the climate change scenarios (i.e. Figure 4 in the main paper, and Figure S2 in the supplementary information). These are in ESRI gridded ASCII format, on a longitude-latitude grid with 1-degree resolution. Refs: 1. Meinshausen, M. et al. The RCP greenhouse gas concentrations and their extensions from 1765 to 2300. Climatic Change 109, 213-241 (2011). Orr, J. C. et al. Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 437, 681-686 (2005). Cao, L. et al. The role of ocean transport in the uptake of anthropogenic CO2. Biogeosciences 6, 375-390 (2009). Yamanaka, Y. and Tajika, E. The role

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).