The integrated modeling framework for Antarctic krill (Euphausia superba) has been extended to include estimates of krill growth consistent with survey data and to use multi-nation survey data collected from 1981 to 2014 near the Antarctic Peninsula. Four models of the population dynamics of Antarctic krill in Subarea 48.1 based on different aggregations of the data are described to illustrate the capabilities of the framework.

Calibrated, integrated, and averaged acoustics data, including estimates of krill (Euphausia superba) biomass density, collected around Elephant Island, the South Shetland Islands, and the Antarctic Peninsula by the U.S. AMLR Program. Data are integrated over depths from about 10-15m down to the bottom or 250m (whichever is shallower) and averaged over 1-nmi intervals.

Zooplankton research in the US AMLR Program focuses on the link between prey production, availability, and climate variability in relation to predator and fishery demands. Annual studies include estimates of krill abundance, and experiments to develop and enhance hydro-acoustic methodologies. Long-term objectives include quantifying the inter-annual and decadal mesoscale (10's to 100's of kilometers) variability in water mass structure, phytoplankton biomass and productivity, and zooplankton (especially krill) associated with potential basin scale climate forcing. Conversely, the microscale (1 to 10's of kilometers) features of the distribution and abundance of krill within the foraging range of krill predators breeding at Cape Shirreff and Admiralty Bay is also studied to resolve local and remote forcing effects on predator foraging success.

---- Public Summary from Project ---- This project is designed to provide an understanding of the interactions between krill, other zooplankton, the physical environment and the predators dependent on krill. This will directly address a number of pressing problems facing CCAMLR (the Commission for the Conservation of Antarctic Marine Living Resources) in its attempts to manage the krill fishery using an 'ecosystem approach'. Expected outcomes: As a result of logistic operations (i.e. diversion to Casey) the 29 days on site allocated to this work was reduced to 10 days. Hence only a fraction of the intended program of work was conducted. Acoustics: Acoustics data (for 38, 120, 200kHz) was collected for the top 250m of the water column for nine and a half of the planned 13 transects in our 60 x 60 nautical mile survey region.

Acoustic densities of Antarctic krill in Scotia Sea from 01162001 to 03032011. Data were collected from research vessels using either Simrad EK500 (years 2001-2004) or Simrad EK60 (2005-2011) echosounders operating at 3 different frequencies (38, 120, and 200 kHz). Raw acoustic data were collected from calibrated echosounders and archived on the vessel and later on shore-based servers. The datasets were ultimately returned to the SWFSC for QA/QC, archiving and review. Krill were identified from these acoustic data using the distorted-wave Born approximation. (Reiss et al., 2008; Fielding et al., 2011). Data were exported using Echoview into gridded bins 5 m deep by 100 m horizontal over a total depth range of 5 m to a maximum of 505 m below the hulls of survey vessels.

The KOMBI (Krill Observational Mooring for Benthic Investigations) seafloor landers are autonomous oceanographic platforms designed to collect high-resolution time-series data on krill species, non-krill species and their seafloor environment across a full year in the Antarctic. Each mooring integrates multiple sensors—such as temperature, salinity, pressure (CTD), video cameras, current profiles and acoustic backscatter—to support long-term ecosystem monitoring and process-based studies. KOMBI moorings are deployed to capture seasonal to interannual variability, improve understanding of pelagic habitat dynamics, and provide continuous observations that complement ship-based and remote-sensing programs. The time series is ongoing and data will be continuously added upon platform retrieval. This dataset contains all data collected from Krill Observational Mooring for Benthic Investigations (KOMBI) seafloor lander platforms. KOMBI platforms were left on the seafloor for one year at depths on the continental shelf and near the shelf break. The minimum depth of a mooring is 350m to avoid collision with icebergs and the maximum depth is 1500m. KOMBI dimensions are 1145 x 1145 x 1300 mm. Moorings are typically deployed in summer months from vessels and are left to collect data for one year (at least). Active acoustic (ADCP and echosounder) data, passive acoustic data, CTD data and video camera footage are available from various instruments installed on the moorings. Active acoustic deployment files, compass calibrations and echosounder calibration files are included. Echosounders were calibrated in a 10,000L tank of temperature-controlled seawater at the Australian Antarctic Division in Kingston, using a 23mm tungsten carbide sphere and a paired Simrad EK80 333kHz echosounder to map the beam. Calibration raw data and code is included to produce Nortek SONAR equation CalibrationOffsetSv for each frequency. Calibration is only available for narrowband frequencies. Data collection began in 2021 and is ongoing.

This dataset contains digitized passive acoustic recordings from a hydrophone connected to an autonomous recording device both moored near the sea-floor in the Southern Ocean. Recordings were digitised at a sample rate of 500 Hz and were continuous over the period of operation. The intended purpose of these recordings was to collect baseline data on the acoustic environment (i.e. underwater sound fields). Underwater sounds that were recorded include sounds generated by Antarctic sea ice, marine mammals, and man-made sounds from ships and geo-acoustic surveys. Marine mammal sounds include calls from blue, fin, humpback, and minke whales. The hydrophone was deployed on a mooring on the Kerguelen Plateau.

ONR Sea State DRI R/V Sikuliaq, Fall 2015 (SKQ201512S, EK60)

ONR Sea State DRI R/V Sikuliaq, Fall 2015 (SKQ201512S, EM302)

Sikuliaq Cruise SKQ201812T (EK60)