Today, 15 October 2017, marks yet another birthday for the Southern elephant seals (Mirounga leonina) on sub-Antarctic Marion Island. For record and analysis purposes, all tagged animals age by one year today. Every year on this day, the sealers (working for the Marion Island Marine Mammal Programme, a University of Pretoria initiative otherwise known as the MIMMP) have one mission: to circumnavigate the entire island in one day to count every single elephant seal hauled out on every single beach! Quite an endeavour, but the sealers take it in their strides…and fast strides they are!
This specific date has been found to be the peak breeding season haul-out for elephant seals on the island. And over the last couple of years, the sealers have managed to count more than 1000 animals on this day, with the numbers increasing ever so slightly with each annual count. This might sound like a lot of elephant seals for such a small island, but this includes adult males, adult females, sub-adults, yearlings, weaners (pups that have just weaned) and black pups (still suckling their moms). Meaning that many of these animals might not grow up to reach adulthood, being able to produce offspring of their own. To put this in perspective, in the history of Marion Island the old sealers (the ones that still killed seals for a living) hunted these animals for quite a number of years (and in large numbers) before it wasn’t considered profitable enough anymore. As there is no accurate account of the numbers of elephant seals on Marion Island before the seal hunting days, one can’t help but wonder what the elephant seal population would have looked like today if those early hunting days never happened.
But for now we are happy to say that the elephant seal hunting days on Marion Island are far behind us and that we take pleasure in studying these amazing marine mammals. There is still so much we don’t know and we look forward to the discoveries that still lie ahead. So let’s wish the “sea elephants” of Marion Island a very happy birthday. May there be many more to come!