You might recall the success of the IMOS Animal Tagging team’s expedition to Macquarie Island last year. Where the team’s work tagging and tracking southern elephant seals (Mirounga leonina) led to the discovery of new bathymetric features, including troughs off the Shackleton Ice Shelf and Underwood Glacier and, a deep canyon near the Vanderford Glacier dubbed the Mirounga-Nuyina Canyon.

And now, just a few days ago, SIMS’ own Dr. Clive McMahon from the IMOS Animal Tagging crew, and a team of dedicated researchers have embarked on another groundbreaking expedition. Teaming up with  esteemed colleagues from Laboratoire d’Océanographie et du Climat: Expérimentations et Approches Numériques (LOCEAN) to deploy advanced CTD (conductivity-temperature-depth) tags on Weddell seals (Leptonychotes weddellii).

French icebreaker, L’Astrolabe, moments before departure from Hobart.
Clive McMahon.
Weddell seal (Leptonychotes weddellii) equipped with a CTD (conductivity-temperature-depth) tag.
Clive McMahon.

This initiative, part of a long-standing collaboration with IMOS Animal tagging and LOCEAN, is not just about gathering data; it’s about piecing together a comprehensive picture of the Antarctic ecosystem. By studying both the water column’s physical structure and the seals’ behaviour, the team aims to measure biological production in the sea ice zone and its cascading effects through the food web.

Their study along the Terre Adélie Coast is especially exciting. As it allows the comparison of the region’s physical ocean structure and biology before and after the significant calving event of the Mertz glacier tongue in 2010. The team hypothesise that this event has profoundly influenced the ecological and oceanographic processes along the coast.

The primary goal of the expedition is to correlate the foraging behaviour of Weddell seals with hydrographic data from both pre- and post-calving periods to understand how the calving has impacted ice/ocean interactions, primary production, and, ultimately, the seals’ feeding performance.

We wished the team bon voyage  on Saturday 27th January, as they set sail aboard the French icebreaker, L’Astrolabe. We eagerly await their return to Hobart in early March with new insights and a deeper understanding of these majestic creatures and their changing habitats.

Weddell seal (Leptonychotes weddellii) equipped with a CTD (conductivity-temperature-depth) tag.
Clive McMahon.