Field Report From Dr. Jay Rotella:
We are now about halfway through the 2023 field season and a little over a week past the peak of pupping, so an update on how things are going and what we’re seeing is in order.
2023 Antarctica Field Team photo by Parker Levinson.
It certainly appears that pup production will be lower this year than it was in the record-high year we had last year. We expect production to be a little higher than the long-term average for 1980-2022 but below the average for the past 17 years. So far, it seems that we might have fewer adult seals in the study area as well, but that’s something that is a bit difficult to document until we conduct and summarize the data from our upcoming surveys.
Photo of a Weddell seal yearling lounging on the sea ice by Jay Rotella.
Many yearlings have been recorded this season.
At this point in the season, our focus starts to shift from tagging pups to conducting surveys of all the animals that we encounter. By doing repeated surveys over the next month, we’ll be able to collect data that will help us estimate the number of males and females in the study area and to classify females as pre-breeders, mothers, and skip breeders. The multiple surveys are important to do as we don’t detect all the animals on any survey: even though the animals are easy to detect when they’re on the ice surface, quite a few individuals are in the water and out of sight on any given survey.
Photo by Jay Rotella of Hutton Cliffs as seen from the Turtle Rock area.
We’re also scheduled to visit several sites at varying distances to the north of our study area to collect small tissue samples from mothers at those sites. Our team’s genetics experts, Dr. Elizabeth Flesch (Montana State University post-doctoral researcher) and Dr. Nancy Chen (assistant professor at the University of Rochester), will analyze genomics data from those samples to try to determine where possible donor sites are in the region that have been the source of so many new mothers that were born outside our study area and that have joined our study population in recent years.
Photo by Jay Rotella of Nate Jourdannais and Rebecca Ballard checking out a beautiful spot along
the glacier wall while previewing the coastal survey route from Cape Evans to Turks Head.
If we can identify likely donor sites, our next goal will be to examine various features of those sites, for example, sea-ice conditions and/or population sizes at each site in different years, to try to identify why animals might be leaving those sites and why the numbers fluctuate across years the way they do.
- Dr. Jay Rotella, Project Lead Scientist and Professor at Montana State University, Ecology Dept.
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