Week 4 Recap

Oct. 30, 2005, McMurdo Station, Antarctica

What a streak we have been on! I am happy to report that the score is now:

Researchers: 7
Seals: 1

It has been a great week with lots of exciting things to report. I would like to thank all the people who have been emailing me when they found out the seals were ahead 1-0. Your support helped push the team forward. We couldn’t have done it without you!

We are interested in collecting data from 3 different age classes of seals: adults, juveniles (1-2 years old) and pups (3-4 weeks old). The pups are just being born now and we will be sampling those animals near the end of November. The pups are quite cute. Their flippers are huge! The seal pup looks like a stuffed animal wearing swimming flippers!
Mother Weddell seal and her newborn pup.
Mother and pup. Notice the large flippers on the pup
Anyways, the juveniles, as I mentioned last week, are much smaller than the adults and are more difficult to find. With an amazing streak of luck, we found 3 of them this week; two of them close enough to find by Pisten Bully & snowmobiles and one of them by helicopter. Shane, Steve and Allyson (a collaborator from another project) took the helicopter trip north of Wohlschlag Bay and found a juvenile and an adult there. The helicopter landed on the sea ice, they got out and sampled the animal and returned to the helicopter to fly back to the lab with the samples.

This week I am going to describe the procedures we go through when we sample a Weddell seal.

Identifying the seal

As female Weddell seals are giving birth now, we are only collecting samples from the male adult Weddell seals. Identifying a seal can be a tricky procedure for the inexperienced seal researcher (like myself!). Essentially we are trying to identify two landmarks on the male seals belly: the umbilicus scar (seal belly button) and the penile opening.

Capturing the seal

After identifying the adult seal as a male, we herd the animal away from his breathing hole. Weddell seals are not used to land (terrestrial) animals except penguins and are very docile. By waving our arms and walking near the seal we can easily get him going in the direction that we want. As I mentioned before however, trying to make the seal go into the seal sled is a totally different ball game. For this reason, we have been sampling the animals in the field rather than transporting the seal back to our mobile camp. The back of the Pisten Bully has become our mobile camp! The great weather conditions have made this new method feasible. However, if the conditions worsen we will have to revert back to transporting the seal to Fish-hut #4.

That is me 'hooding’'an adult Weddell seal.
Once we have successfully herded the seal away from the breathing hole, we need to restrain it so that we can sample him. The first thing that we do is ‘hood’ him. This is simply putting a black bag over his head. Hooding the seal serves two purposes: (1) it calms the seal and (2) it protects it eyes from damage. Since the sedative we give to the seal dilates the pupils, providing a dark environment protects the eyes from the bright sunlight.

Sampling the seal

Now that the seal is restrained we can begin our sampling procedures. The first thing we do is weigh the seal using a large force transducer (scale) that hangs from a tripod (see picture). After weighing the seal, we then obtain very small muscle samples from the back muscles. These samples are similar to the samples elite athletes provide to have their muscle analyzed in a laboratory to determine how efficient their physiological machinery is working. Each sample is divided up and used for RNA analysis, protein analysis, cell culture, immuno-histochemistry and cellular enzyme analysis. Finally, we measure the length and axial girth of the seal. The sampling procedures take roughly 30 minutes.
Shane and Allyson are preparing to weigh the juvenile seal.
Shane releasing the seal. Rebecca looking on from our mobile camp (back of the Pisten Bully).
This has been a very successful week for us. We are now ahead of schedule with our sampling which is a real bonus because you never know when the weather here will change. Dr. Kanatous and I are scheduled for another helicopter flight this coming week in hopes of finding more juveniles! Keep your fingers crossed!

Some other pictures:
Adelie penguins enjoying the sun
Barne glacier with Mt. Erebus in the background
Dr. Steve Trumble taking a rest with a juvenile Weddell seal.

Polar Science
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