An integrated, age-structured model was fitted to different combinations of survey data using two forms of selectivity (logistic or double-logistic) with time-constant or annually varying selectivity to investigate the population dynamics of Antarctic krill (Euphausia superba) near the Antarctic Peninsula. The data were from surveys conducted by the U.S. Antarctic Marine Living Resources Program around the South Shetland Islands from 1992 to 2011. Two indices of krill biomass based on (1) trawl-net samples and (2) hydroacoustic sampling were combined with length-compositions from the nets. Sixteen model configurations using different combinations of the two biomass surveys with the various options for modeling selectivities were examined.

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.

This data set is a supplement to the R package, EchoviewR. EchoviewR is a free software package that acts as an interface between R and Echoview. It uses Component Object Model scripting to enable automated processing of active acoustic data. This data set contains the data necessary to run the vignette tutorials and package examples. The .raw files are acoustic data collected using an EK60 echosounder. They are a subset of the full acoustic data collected on the Krill Acoustic and Oceanographic Survey (KAOS) off Antarctica in the summer of 2003. The .EV template file was created using Echoview v6.1. The .ecs calibration file, .evl line object file and .evr region files are for use with this template. The region files designate off transect regions. The three pdf vignettes contain examples of reading data using EchoviewR, conducting school detection and running biomass estimation of Antarctic Krill. These data are intended only as a supplement to demonstrate the use of EchoviewR. This data is a subset of the KAOS data and as such, must NOT be used to formally estimate krill biomass. These data are a subset of data described in the metadata record at the provided URL.

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.

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 in 2006.

This Bio Acoustic data was collected in August 2010 under the IMOS Ship of Opportunity (SOOP) Bio Acoustic (BA) program on Sealord F.V. Rehua (IMOS platform code: ZMRE). Departed: Australia, August 13, 2010 Arrived: New Zealand, August 17, 2010 Bio acoustic signals allow understanding how mid-water prey species (known collectively as micronekton) such as small fish, squid, krill and jellyfish are distributed. Mid-water prey form the core of the ocean food web, transferring energy from primary producers at the ocean surface to top predators such as tunas, billfish, sharks, seals and seabirds.The mass and distribution of micronekton reflects broad-scale patterns in the structure and function of the ocean, as well as the dynamics of marine ecosystems. Acoustic mapping is done from fishing and scientific vessels that are equipped with scientifically-calibrated 38 kHz digital echo-sounders that record a slice of acoustic backscatter to a depth of 1500 meters.

Dataset contains continuous underway measurements of ship’s position, sea surface temperature, salinity, turbidity, fluorescence, air temperature, barometric pressure, relative humidity, plus wind speed and direction. These data are part of a long term ecosystem project centered on the South Shetland Islands of the Antarctic Peninsula, Antarctica. The datasets incorporated into this archive have been collected by researchers affiliated with the U.S. Antarctic Marine Living Resources (AMLR) Program under the National Marine Fisheries Service (NMFS); funding for this project was from the NMFS AMLR Program. Actual data collected any given year varies, dependent on funding availability for resources, staging and sea days.