Bonus Projects

The Baltic Seal - BONUS BIO-C3

Join the adventures of our Baltic Seal in this journey through his life history, and the history of the seal populations, in the Baltic Sea, and discover how their interactions with humans affect the ecosystem. As a postdoc trying to model the ecological role that the seals have in the Baltic Sea, especially in relation to fisheries, I spend much of my working time in front of a computer. This is my way to get closer to the Baltic Sea water and its fauna.
15.03.2016 12:56

From birth to weaning

David Costalago

I have never seen a seal in the Baltic (yet). And although I might not see any during my time working in the BIO-C3 project, my task here is utterly related to the Baltic seals. For that reason, I want to inaugurate my series of posts for the BONUS projects’ blogs with a real story on the life history of these marine mammals in the Baltic Sea.
The below narrated conversation and events took place in March 2015 on an out-of-the-way island in the Archipelago Sea.

23227278570_f90fd8dbc7_b
Grey seal cow and pup suckling. Author: Africa Gómez, https://www.flickr.com/photos/52910542@N07/23227278570

- Mum, how old am I? 
- Sixteen days old as of this morning.
- And how old are you?
- I’m about to turn 45 sweetie.
- Wow, that’s very old.
- Yes, I guess. I only know of a couple of ladies around here that are older than me.
- What about the males; are there any males older than you mum?
- I doubt it. Anyway, you don’t see many males on this beach during this season… it’s breeding time and they have to earn their right to be nearby.

While wondering what it would take to gain access to a beach when he was an adult (in 6 or 7 years), the young character went back to what he could do better: suckling from his mum’s breast. All he knew at that time was that he needed to get bigger as fast as possible, and his mother’s extremely rich milk would undoubtedly serve that purpose. With about 50-60% fat, the milk would make his body weight increase from roughly 16 kg at birth to almost 40 kg in just two weeks. That means he would be gaining about 2 kg/day!! What he didn’t know yet was why he had to accumulate so much energy in such a short time.

Later that day, after a short nap, the little pup seal, hit by curiosity, wanted to know more about how they arrived at that particular beach, and where all the seals go when the breeding season comes to an end. But when the pup turned around, rolling over his chubby back, to ask his mother, she was gone. For good. 
He was on his own. And he was hungry. After a couple of hours trying to find his mother, calling her as loud as he could, he realized that he had to do something different if he wanted to survive. He then remembered the stories that the adult seals would tell, when coming in and out of the water, about the fish they were eating in the sea.

Although a bit disoriented, and in spite of not having seen his mother ever doing that, he managed to crawl his way to the surf. But when he reached the waves… jeez, that water was freezing!

It took him a very long time, more than 2 weeks, until he gathered the courage (and was hungry enough, as he had been living off his blubber reserves) to enter the water. Also, during those days, he moulted his fur completely, and was now ready to go underwater without even getting wet. He actually seemed to know exactly what he had to do there. He knew how to swim; in fact, he was very good at that. And he was also able to recognize a fish as a meal the moment he first saw one. The little pup started chasing fishes… But that is another story.



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