Season Update From Field Team Leader Parker Levinson:
Pupping is winding down, and we are making great progress tagging every pup in our study area. This is one of our big goals each season in order to know how big the birth cohort is and the age of seals when they return to the study area later in life. Over half the births happen within 9.5 days, peaking at the end of October, so pupping is a very busy time during our season. A large portion of births occur in pupping colonies that tend to be near land or islands where consistent cracks in the sea ice form each year.There are anywhere from 8-14 pupping colonies that occur in our study area depending on the year. Some of the seal colonies are small, like Inaccessible Island with less than 25 seals, but others, like Hutton Cliffs, can have many hundreds of seals.
Aerial view of Weddell seal colony at Hutton Cliffs. Photo by Parker Levinson.
A really crucial piece of data we collect for each pup is who their mom is, allowing us to look at maternal traits that may affect pup survival and to form complete reproductive histories for each female (like the 31 and 32 year old females we found this year). While moms and pups stick together throughout the 35-day nursing period, it is easiest to definitively know the mother the younger the pup is because there is less swimming and separation at early ages. We also like to know the birthdates of pups, which is another aspect of environmental variation we’ve looked at. And knowing birthdates allows us to weigh pups at specific points throughout their development to look at mass transfer between mom and pup.
Two large pups hanging out together. Photo by Parker Levinson.
With these objectives in mind, we try to visit the major colonies every other day. Sometimes bad weather prohibits us from accomplishing this, but for the most part, we’ve had success even with a smaller crew size this year.
While pupping season is super fun, the tail end of it is one of my favorite times in the season because there are so many different sized pups in the colony. There are still a couple new pups being born so we get to witness small newborns. At the same time, we have pups that are more than 20 days old and over 200 lbs now. Seeing the discrepancy between different aged pups is quite fun! We are looking forward to watching the pups grow up, learn to swim, and continue napping.
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