Antarctic Weddell seal tagging project- Deployments, Take 2

Daniel Costa, Jennifer Burns, Mary Zavanelli, Michelle Shero and Luis Huckstadt, from McMurdo Station, Antarctica -

 


Field team January 2011 with the last tagged Weddell seal . First row (left to right): Dr. Dan Costa, Dr. Mary Zavanelli. Standing (left to right): Luis Huckstadt, Dr. Jennifer Burns, Michelle Shero . Photo by Dan Costa. 

 

After successfully deploying 22 tags and recovering 6 during year 1 of the Antarctic Weddell seal tagging project… we set out to do it all over again for year 2. On January 18th the field team landed once again on the ice. Two groups had come to work together on the project: Dr. Dan Costa with Dr. Mary Zavanelli and graduate student Luis Huckstadt (from U.C. Santa Cruz), and Dr. Jennifer Burns with graduate student Michelle Shero (from U. of Alaska Anchorage). The new people on the ice underwent survival training courses, which included “Happy camper” (sleeping in a snow trench). After more sea ice and snowmachine training, the entire group was finally cleared to leave the station and start doing science!

 


Weddell seal swimming in a melt pool. Photo by Michelle Shero

 

First thing first, we needed to find out where the seals were. We conducted an aerial survey to find large colonies of seals. The larger the group, the better chance we would have of finding animals that had already molted and had their new fur coat for the year (a very important detail in attaching the satellite-linked dive recorders!). We started finding molted seals via snowmachine at the Pressure Ridges, with large cracks and rolling white hills formed by the ice shelf meeting sea ice. The group deployed the first tag of the season there on a very large (almost 450 kg, that’s ~1,000 pounds) female Weddell seal on January 22nd, while working in -15°F weather. The animal was sedated for handling, the tag (which will collect behavioral dive data and oceanographic data for the Ross Sea) was attached, and physiology samples were collected-while the new team members learned the ropes.

 

A Weddell seal with her new “hat” that will collect behavioral dive data and oceanographic data throughout the winter. Photo by Michelle Shero 

 

We wanted to tag seals in multiple areas, so next we took helicopter (helo) flights across McMurdo Sound and found more animals further north at Tripp Bay and Dunlop Island. The team enjoyed it up there-the weather seemed to always be much nicer- and we were able to deploy 10 more tags before storms came in and broke apart the ice (it’s a good thing we started there early!). Once we started a procedure, everything needed to be fast but still efficient. Working with such large animals- that like to roll around- and in such cold weather made it all that much more tricky. But, with each animal the team was able to figure out what worked best (…and what did not work so well) and the whole process began going very smoothly. We deployed our 20th and last tag on February 9th at night (although, it still looked like broad daylight outside) on a very cooperative seal.

 

Adelie penguin rookery at Cape Royds. Photo by Michelle Shero

 

In addition to the Weddell seals, we saw some more wildlife around the Antarctic. One day, while on a helo flight returning from a day in the field, we passed a group of literally 100 orcas! We saw an Adelie penguin rookery and numerous Emperor penguins too (sometimes they would just walk right up to us to see what we were doing with the seals). We also had the opportunity to go inside the historic explorer huts- Scott’s hut even had his old science lab benches and equipment inside.

 


Field team January 2011 inside Scott’s hut at Cape Evans. From left to right: Dr. Jennifer Burns, Dr. Mary Zavanelli, Dr. Daniel Costa, Michelle Shero, Luis Huckstadt. Photo by Dan Costa.

 

The team will analyze Weddell seal dive behavior, habitat utilization, oceanographic parameters, and physiology samples- until their return to the Antarctic in October to recapture the animals for seasonal comparisons.