MSc PROJECT: HOW DO SEALS BREATHE? (WRAP-UP)



by Judith Ullmann

 UiT The Arctic University of Norway, October 2019: I completed my master’s on the respiratory physiology of the harp seal under the main supervision of Prof. Lars P. Folkow at the Department of Arctic and Marine Biology – with Grade A, hurra!

The steps to success: I wrote my magnum opus to date (thesis), gave a 45-minute public presentation (defense Part 1), and took a two-hour oral exam with the examination committee (defense Part 2). Easy, right? The number of steps before these final three, I did not bother counting. – A word of advice… ; )


My project in a nutshell
Seals are special when it comes to breathing. They have lungs like we do and breathe air to get the oxygen needed for metabolic processes (in short, to run the body chemistry that keeps them alive). Unlike us, these marine mammals can (and usually do) spend about 90% of their time at sea underwater. Beneath the surface, they hunt and travel and rest for long periods, sometimes hours. Surface stopovers to trade accumulated carbon dioxide for a new load of oxygen last only seconds to minutes.


Scientists agree that the way seals breathe must be very efficient. But little is known about the respiratory anatomy (lung size, dead space) and the dynamics of lung ventilation in these animals.










SURFACE BREAK – harp seal «Yellow» between dives. Take a deep breath! Photo: Judith Ullmann (from video by Dr. Martin Biuw)


Why bother with how seals breathe?
Understanding the “quirks” of seal respiration helps in designing metabolic (respirometric) studies to estimate the energy expenditure of individuals and, by extension, entire populations (relevance: fisheries management). The harp seal, an arctic top predator, with its nearly 10 million animals is the most abundant pinniped in the northern hemisphere. This is a force to reckon with in food web studies.
My project comprised three parts: an anatomical study to determine the size and proportional makeup of the respiratory tract (lungs and airways), and two ventilatory studies to investigate the breathing patterns of unrestrained seals after standardized exercise and between voluntary dives. (The last study was conducted by my supervisors; I inherited the data.) I spent the bulk of my master’s in the Seal Lab, training adult and juvenile harp seals for my exercise study.

SEAL TRAINING – the beginning. Learning the ropes from supervisor Dr. Mario Acquarone. Photo: Roman Bachleitner
 
DATA COLLECTION PILOT – with supervisor Dr. Marie-Anne Blanchet, head trainer. We are eager to see what our first recordings look like! Photo: Dr. Mario Acquarone
 
DAILY ROUTINE – seal kitchen. I prepared over 3 tons of fish during my year of animal training. Many buckets to clean… Photo: Judith Ullmann
 
SEAL TRAINING – advanced, working alone. I practice measuring girth with one of our juveniles. Training videos on ResearchGate (Project log). Photo: Judith Ullmann
WEST ICE, GREENLAND SEA – R/V «Helmer Hanssen» approaching seal breeding grounds. I prepare for anatomical data collection at −20°C in the pack ice. Photo: Judith Ullmann
A DAY OFF – visiting the Kaldfjord seal enclosure. Marie Emilie Sørdal Bue (right) and I (left) help supervisor Dr. Martin Biuw during an experiment. (I ended up inheriting some of the data…) Photo: Judith Ullmann
 
The thesis was just the beginning…
In my thesis, I answer these questions and more (relax, no spoiler alert):
 Do harp seals have larger lungs or breathe deeper than non-diving mammals? How do they upregulate ventilation to cope with the increased oxygen demand during physical activity? Does respiration differ in water versus on land – where many studies are run due to simpler logistics?
So far, I have presented results of my research at the:
  • 1st NAMMCO Marine Mammal Student Symposium (6 Feb 2019) – Tromsø, Norway conference abstract
  • WMMC’19: World Marine Mammal Conference (9–12 Dec 2019) – Barcelona, Catalonia, Spain visit my blog post
 

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