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).

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.

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

Distribution and abundance of zooplankton, krill and fish were observed on the K-axis transect using deployments of RMT1+8 net. Towing speed of the RMT1+8 were approximately 2 knots. All krill, fish and squid in the catch were sorted, identified to species and counted. The density at each station were determined from the counts per calibrated flow-meter readings attached to the net. Morphometric measures were taken and, for larger taxa. List of files K-Axis Morph combined_for data centre.xlsx: Morphological data for all krill and zooplankton captured in RMT-8 net haul. RMT data entry_v1_for data centre.xlsx: Trawl data. RMT8 filtered volume_for data centre.xlsx: Filtered volume for each haul. Map_all.tif: Map showing all trawl stations. Map_RMTR.tif: Map showing only regular trawl stations. Map_RMTT.tif: Mapn showing only target trawl stations. K-Axis description This dataset includes biological data from “K-Axis voyage, 2016 and “Voyage 3, 2015”. [Data from K-Axis voyage, 2016] Distribution and abundance of zooplankton, krill and fish were observed on the K-axis transect using deployments of RMT1+8 net. Towing speed of the RMT1+8 were approximately 2 knots. All krill, fish and squid in the catch were sorted, identified to species and counted. The density at each station were determined from the counts per calibrated flow-meter readings attached to the net. Morphometric measures were taken and, for larger taxa. -List of files- K-Axis Morph combined_for data centre.xlsx: Morphological data for all krill and zooplankton captured in RMT-8 net haul. Map_all.tif Map_RMTR.tif Map_RMTT.tif RMT data entry_v1_for data centre.xlsx: Trawl data. RMT8 filtered volume_for data centre.xlsx: Filtered volume for each haul. [Data from Voyage 3, 2015] The Australian Antarctic research and resupply vessel, RV Aurora Australis, was directed to undertake an opportunistic marine science survey for 17 days during 21 February to 10 March 2015 using ship time that became available due to unexpectedly favourable ice conditions for Mawson station resupply. The purpose of this opportunistic Marine Science work was to assess: 1. The spatial variability, particularly along the shelf break, of the prey field for penguins, flying seabirds and marine mammals in East Antarctica. 2. The small scale variability of prey in key foraging locations near to land-based colonies of penguins and flying seabirds in East Antarctica. 3. Feasibility and potential of utilising annual station resupply voyages as a cost effective means to undertake monitoring and research to better understand the ecosystem in the region. The survey completed 5 acoustic box surveys including a total of 53 RMT target and routine trawls, 6 demersal trawls, 131 phytoplankton samples from underway sampling, and 214 hourly observations of predators. These activities were successfully supervised remotely. -List of files- emm-15-22.pdf: Prelminary report of the voyage to CCAMLR WG-EMM Figure_V3_all_euphausiids.pdf: Map of Euphausiid abundance distribution. Figure_V3_Clione_antarctica.pdf: Map of Clione antarctica abundance distribution. Figure_V3_crystal_krill.pdf: Map of Euphausia crystallorophias abundance distribution. Figure_V3_frigida.pdf: Map of Euphausia frigida abundance distribution. Figure_V3_larval_fish_abundances.pdf: Map of fish larvae abundance distribution. Figure_V3_superba.pdf: Map of Antarctic krill abundance distribution. Figure_V3_tmacrura.pdf: Map of Thysanoessa macrura abundance distribution. V3_final_for data centre.xlsx: Trawl station data and density data of each taxa caught. Voyage 3 Marine Science Program Final.docx: Voyage report.

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.

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

These data were collected during the BROKE-West voyage of the 2005-2006 season. They are numbers of krill larvae per cubic metre of water at each of the stations at which data were collected. The data cover three species of Antarctic krill - Euphausia crystallorophias, Euphausia superba and Thysanoessa macrura. The superba data have been published in the Kawaguchi et al paper, "Krill demography and large-scale distribution in the Western Indian Ocean sector of the Southern Ocean (CCAMLR Division 58.4.2) in Austral summer of 2006". The data for the other species will be presented in a forthcoming paper by Kerrie Swadling. This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679).

Taken from the "Supporting Information" for the main paper. See the referenced papers for more information. Our results are based on numerical simulation of Southern Ocean sea ice, conducted using the Los Alamos numerical sea-ice model CICE version 4.0 [CICE4; Bailey et al., 2010] configured in stand-alone mode on a 0.25 degree x 0.25 degree grid, extending to 45 degrees S, with 3-hourly output [Stevens, 2013]. The atmospheric forcing for CICE4 came from the hemispheric forecasting model Polar Limited Area Prediction Systems [Polar- LAPS; Adams, 2006] and ocean forcing from the global ocean general circulation model Australian Climate Ocean Model [AusCOM; Bi and Marsland, 2010]. The model is well-constrained in its representation of processes of sea ice formation and melt, and comparison with observed areal ice extent shows minimal deviations over the 1998-2003 period, particularly during winter [Stevens 2013]. Stevens [2013] evaluates the sensitivity of the model to the number of ice thickness categories. Sea ice thickness sensitivities in the CICE model are considered in detail in Hunke [2010, 2014]. For the warm climate scenario, changes were implemented that are consistent with the A1B scenario from the Fourth Assessment from the IPCC [Meehl et al., 2007]. This is a mid-range scenario that assumes rapid economic growth before introduction of new and more efficient technologies mid century. Specifically, the following changes were applied uniformly to the current climate forcing field for a single year: a 2 degrees C increase in air temperature, a 0.2 mm/day increase in rain, a 1.5% increase in cloud fraction, a -2.3 hPa change in surface air pressure, a 25% increase in wind, a 12 Wm-2 increase in long wave downward radiation and a 20% increase in humidity. Outputs and forcings from CICE4 that are relevant for consideration of under-ice habitats for larval krill include: snow depth, ice thickness, ice concentration, movement, ridging rate, day length (dependent on day-of-year and latitude), radiation above the ice (influenced by cloud cover), and radiation below the ice (influenced by ice and snow depth). Table 1 in the main text describes how these were used in the following two filters and one overlay for evaluating the location and suitability of potential larval krill habitat during winter. Taken from the abstract of the main paper: Over-wintering of larvae underneath Antarctic pack ice is a critical stage in the life cycle of Antarctic krill. However, there are no circumpolar assessments of available habitat for larval krill, making it difficult to evaluate how climate change may impact this life stage. We use outputs from a circumpolar sea-ice model, together with a set of simple assumptions regarding key habitat features, to identify possible regions of larval krill habitat around Antarctica during winter. In particular we assume that the location and suitability of habitat is determined by both food availability and three dimensional complexity of the sea ice. We then compare the combined area of these regions under current conditions to that under a warm climate scenario. Results indicate that, while total areal sea-ice extent decreases, there is a consistently larger area of potential larval krill habitat under warm conditions. These findings highlight that decreases in sea-ice extent may not necessarily be detrimental for krill populations and underline the complexity of predicting future trajectories for this key species in the Antarctic ecosystem.

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