We're excited to bring you a special edition of In the Spotlight—our series that highlights the expertise and innovation of Echoview users in 70 countries. Their work advances hydroacoustic research and applications, providing valuable insights to the wider Echoview community.
In this edition we were pleased to catch up with Dr. Abbie Smith, a Fisheries Acoustics Research Scientist with the Australian Antarctic Division (AAD) Southern Ocean Ecosystem Program, where she prepares and analyses echosounder data for a suite of moorings that are dedicated to understanding the biomass and behaviour of Antarctic krill.
Abbie also supports Australia’s contribution to the sustainable management of the Antarctic krill fishery through the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), and is interested in exploring how active acoustics can support the investigation of marine biogeochemical cycles. She completed a Bachelor of Marine and Antarctic Science with Honours at the University of Tasmania (UTAS), which also led her to pursue a PhD at UTAS. “My thesis focussed on the sources and bioavailability of the trace metal iron along Antarctic coastlines (which included analysing sea ice, sediments and dust, as well as krill, whale, seal and penguin poop).”
Abbie recently led a team of researchers from the AAD, the Australian Antarctic Program Partnership (AAPP), UTAS, the University of New Hampshire, Aqualyd Limited, and Echoview Software on a publication which examined Antarctic krill biomass, behaviour, and their role in carbon export. The study challenges established theories about the impact of krill movement between the Southern Ocean’s surface and seafloor depths, with implications for climate models and mitigation strategies. Thank you, Abbie, for sharing your story with us.
What was your research topic, and which echosounders did you use for this work?
Our recent article in Science titled “Antarctic krill vertical migrations modulate seasonal carbon export” used a seafloor lander to assess the diel vertical migration behaviour of Antarctic krill across a whole year in Prydz Bay, East Antarctica - including under the sea ice in winter, which is data that is nearly impossible to collect. The lander - dubbed “Krill Observational Mooring for Benthic Investigations” or KOMBI for short – was equipped with an upward looking echosounder and ADCP (Nortek Signature 100) which operated on and off every seven minutes, as well as deep-sea cameras and lights. The KOMBI moorings were purpose-built and designed by inspired AAD krill scientists (Rob King, among others) for observing krill near the seafloor, beyond the reach of traditional vessel-mounted echosounders. Because krill are known to play a large role in the transport of carbon from surface waters to depth, we used the echosounder data to explore how variability in krill vertical migration patterns influenced their particulate organic carbon export.
How did Echoview assist your research?
Co-author and Echoview Software’s Chief Scientist Briony Hutton was a tremendous help in processing and analysing data. Briony also contributed significantly to reviewing the manuscript and supporting it through to publication.
"We used Echoview to read the echosounder data from the Nortek instrument, and created a dataflow to isolate krill targets using dB-differencing from the 120 - 70kHz frequencies."
We exported the krill data on a 1 metre x 1 hour grid and used the integrated backscatter of each cell to estimate the weighted mean depth of krill every hour for the year.
What were your key findings?
Our echosounder data revealed that across the year, only a quarter of the krill population participated in vertical migrations between the epipelagic zone (<200m) and mesopelagic zone (>200m). The greatest fraction of krill migrating into mesopelagic waters occurred in winter (when surface primary productivity was lowest), where krill performed full water column migrations from the surface to the seabed. Consequently, non-migrating krill exported 8.4 mg C m−2 day−1 from sinking faecal pellets released in the upper water column, whereas migrating krill injected considerably less particulate organic carbon (1.3 mg C m−2 day−1) into the mesopelagic zone over a full year. Carbon injection by migrating krill was highly seasonal, with the largest contributions to carbon flux in winter (when a greater proportion of migrating krill were present), but overall vertical migration contributed less than 10% of the total krill particulate organic carbon flux. Our model suggests that previous estimates of carbon injection by migrating krill, which are based on assumed rather than observed vertical migration behaviour, may have been overestimated and that the Antarctic krill migrant pump has a minor contribution to particulate organic carbon export.
The mooring in Prydz Bay and sample data that was recorded. A: the KOMBI seafloor lander, B: the deployment location in East Antarctica, C: 120 kHz echograms, D: video footage stills showing krill near the seafloor. See the first paper in the references list below for further details.
How did you get started working with echosounders and Echoview?
During my PhD I was lucky enough to join two Southern Ocean research cruises on RV Investigator. The first voyage focussed on trace metal sampling, while the second focussed on performing a biomass survey for krill in East Antarctica. This voyage was my first experience using active acoustics, and I was fortunate to learn from some incredible talented fisheries acousticians from New Zealand and Australia. Since then, I have used Echoview to calibrate a variety of instruments (EK80 and Nortek), and to process imaging sonar data in the krill aquaria at the Australian Antarctic Division.
Links to published research
Papers:
Smith, A. J. R., Wotherspoon, S., Ratnarajah, L., Cutter, G. R., Macaulay, G. J., Hutton, B., King, R., Kawaguchi, S., & Cox, M. J. (2025). Antarctic krill vertical migrations modulate seasonal carbon export. Science, 387(6732). https://doi.org/10.1126/science.adq5564
Smith, A. J. R., Wotherspoon, S. J., & Cox, M. J. (2023). Per-length biomass estimates of Antarctic krill (Euphausia superba). Frontiers in Marine Science, 10. https://doi.org/10.3389/fmars.2023.110756
Cox, M. J., Macaulay, G., Brasier, M. J., Burns, A., Johnson, O. J., King, R., Maschette, D., Melvin, J., Smith, A. J. R., Weldrick, C. K., Wotherspoon, S., & Kawaguchi, S. (2022). Two scales of distribution and biomass of Antarctic krill (Euphausia superba) in the eastern sector of the CCAMLR Division 58.4.2 (55°E to 80°E). PLoS ONE, 17(8), e0271078. https://doi.org/10.1371/journal.pone.0271078
Smith, A. J. R., Ratnarajah, L., Holmes, T. M., Wuttig, K., Townsend, A. T., Westwood, K., Cox, M., Bell, E., Nicol, S., & Lannuzel, D. (2021). Circumpolar Deep Water and Shelf Sediments Support Late Summer Microbial Iron Remineralization. Global Biogeochemical Cycles, 35(11), e2020GB006921. https:/doi.org/10.1029/2020GB006921
Echoview user stories
Do you have an Echoview user story, photo, or anecdote you wish to share? You can participate by emailing us at info@echoview.com.
