Weddell Seal Science

Wildlife Geneticist Dr. Elizabeth Flesch Reports From Granite Harbor, Antarctica!

Special Field Report By Dr. Elizabeth Flesch:

Where do the mystery seals come from??

Granite Harbor, perhaps?

One of the reasons we can gain so much information from studying the Weddell seal population in Erebus Bay is because the seals who are born there typically return as adults to have their own pups in the same location. Because we tag every seal who is born in the study area each year, we can identify seal moms who originated in a different area due to a lack of tags. Every year our team observes moms lacking numbered tags who come in from other areas to have their pups. We are interested in learning from where these moms are coming and what might affect their decision to give birth in Erebus Bay, instead of their natal colony. It is quite a mystery!

We are genetically sampling other Weddell seal colonies at a variety of distances from the Erebus Bay study area to find an answer to these questions. The project has now sampled inside the study area and at four Weddell seal colony sites along the Victoria Land Coast: (1) Marble Point (~87 km away from McMurdo Station), (2) Granite Harbor (~137 km from McMurdo Station), (3) just south of the Drygalski Ice Tongue (~262 km from McMurdo Station), and (4) in Terra Nova Bay (~364 km from McMurdo Station).

Cursor over the dots in the map above to identify the Weddell seal pupping colonies
visited outside the Erebus Bay study area to obtain Weddell seal genetic samples.
This interactive map was prepared by Dr. Jay Rotella.

To obtain a genetic sample, we take a small piece of tissue from a seal’s hind flipper. Don’t worry about our impact on the seals; in the wild Weddell seals bite each other on the hind flippers, and our efforts have comparatively less of an effect. Some of them snooze right through it, and all of them go back to sleeping within minutes of being sampled. 

Preparing Weddell seal genetic sample vials for use in the field.

Today we visited Granite Harbor to collect genetic samples from 33 moms there! We flew by helicopter to Granite Harbor, which is about 80 miles from Erebus Bay. Once there, we split into multiple groups to collect the samples. We also checked for tagged animals while we were at Granite Harbor, and we found one female who was actually born in Erebus Bay, which suggests that there might be a very minimal amount of animals exchanging between the two populations. Hopefully these genetic samples will help answer how much exchange is going on. Once the tissue samples are collected, we split them in half and store them in ethanol in a -80C freezer. Splitting them in half creates redundancy so in case something happens to one batch, we still have the other batch.  

The 2023 field team as they head out to visit the Weddell seal colony at Granite Harbor, Antarctica.
Photo by Brian Minnear.

We have also sampled three other seal colonies to compare with Erebus Bay. Using modern sequencing technology to analyze the seal DNA, we can evaluate how related the seals found in different locations are. Based on that information, we can determine the most likely birthplace of the mystery moms found in Erebus Bay. We look forward to sharing those results in the future!

- Elizabeth Flesch (she/her)
Montana State University PostDoctoral Researcher working with Weddell seal population genomics collaborative project Principal Investigator, Dr. Nancy Chen of the University of Rochester, and co-advised by Dr. Jay Rotella of Montana State University.

Parker Levinson's New Video On Weddell Seal Surveys!

Special Video Report From The Field By Parker Levinson:

"We've been doing surveys across two days since we're working from McMurdo Station. So we're currently in the middle of our third survey, and hoping to finish up tomorrow if the weather holds," Parker reports. "I'm having a lot of fun making these short little clips, and hopefully people are enjoying and learning from them!"

Weddell seal surveys recording all of the Weddell seals present in the entire Erebus Bay study area are done several times throughout the pupping season. Several full surveys are needed during the pupping season to more accurately determine the size of the population because not all the seals are on the surface and visible at any given time.

Parker (she/her) is the 2023 Antarctica field team leader, and is a Masters student in the Ecology Department at Montana State University. In addition to her research work and graduate studies, she is proficient in creating short science story videos in extreme environments such as Antarctica. More of Parker's video work is available on our Weddell Seal Science YouTube Channel. We hope you enjoy Parker's latest science video creation!

- Mary Lynn Price

eBook Author Jeremy Schmidt Reads An Excerpt on Antarctic Heroic Era Pioneer Edward A. Wilson

In our latest Weddell Seal Science Podcast episode, "Weddell Seals" multimedia ebook author and creator Jeremy Schmidt reads an excerpt from the ebook on the early pioneering work in the study of the Weddell seals of Erebus Bay by British Antarctic explorer, naturalist and artist Dr. Edward A. Wilson. Wilson gives a vividly accurate portrayal of encountering a Weddell seal!

Edward Wilson was a member of Robert Falcon Scott's ill-fated expedition to reach the South Pole, and died on the return from the South Pole in 1912. His scientific Antarctic Notebooks are filled with beautiful accurate drawings and accompanying paintings of the mammals and birds he encountered in Antarctica.

Our podcast is available on Apple Podcasts and Spotify. We hope you enjoy Jeremy's reading from our new ebook's section on Edward Wilson and Weddell seals!

- Mary Lynn Price

Weddell Population Project Genomics Scientist Now On The Ice!

Dr. Elizabeth Flesch, MSU postdoctoral genomics researcher and 2023 field team member, has arrived safely at McMurdo Station for her first visit to Antarctica. She will receive training in sea ice safety, then join the rest of the field team working in the Erebus Bay Weddell seal pupping colonies.

Elizabeth (she/her) notes upon arrival, "I look forward to seeing the seals in person after working with their genetic data on a computer for the past several months! Genetic tools provide an exciting opportunity for us to potentially identify from where immigrant seals originated. Similar to human ancestry services, we can study DNA from seals to understand who is related to whom. This season we are sampling other seal colonies that are possible sources of immigration to serve as a comparison to locally born seals."

We look very much forward to covering more of the Weddell seal population genomics work in future posts!

- Mary Lynn Price

Parker Levinson Reports On The Isolated Colony Of Weddell Seals At White Island!

Special Field Report From Parker Levinson:

We just got back from our first trip out to White Island, an isolated seal colony about 20 miles south of McMurdo station. It’s a really interesting story.

New field video report from Parker Levinson on the isolated White Island colony of Weddell seals.

Usually, Weddell seals reproduce on sea ice or frozen ocean. They’re able to swim miles under the sea ice to form these large pupping colonies away from predators. Then, when the ice breaks out, the seals go elsewhere. We’re not quite sure where they go in the winter months; some probably stay in Erebus Bay, others travel north up the coast in search of food. But what the Erebus Bay seals have in common with the 200,000 other Weddell seals around the Antarctic continent is that they utilize sea ice to breed and to haul out on (Larue 2021). 

A Weddell mom with her new pup at the isolated White Island pupping colony. Photo by Parker Levinson.

The White Island seals do not. The White Island seals live on an ice shelf, which is basically a frozen glacier. The thought is that decades ago, most likely in the late 1940s, the ice shelf broke out, allowing seals from Erebus Bay to swim to White Island. As the ice shelf grew back, the seals got trapped behind it, resulting in an isolated population.

Weddell mom with new pup in the distance at White Island. Photo by Parker Levinson.

Geneticists believe the population was founded by two males and three females and is now in its 3rd or 4th generation (Gelatt 2009). To continue surviving and reproducing, seals must find food beneath the ice shelf, swimming through thick ice and extreme darkness. We really don’t know too much about how the life history of seals at White Island differs from those at Erebus bay, although we do know they reproduce a little less frequently.  

Heading back to the helicopter at White Island, Antarctica. Photo by Parker Levinsoon.

We go to White Island 1 or 2 times every year to tag the pups, see who is still alive and hauled out on the ice, and collect genetic samples for our collaborators. We take a helicopter out there, conduct an aerial survey of the seals, and then land on the ice shelf to begin our tagging efforts.

Video from a previous pupping season of Jesse DeVoe and Jessica Farrer flying out to
White Island to record the isolated Weddell seal pupping colony there.

We saw 5 adults out there this time and tagged 2 live pups, which is a pretty average year. While we don’t get that many seals out there, visiting White Island always reminds me of how resilient these animals are. 

- Parker Levinson (she/her), 2023 Field Team Leader and MSU Masters Student

Genomics Researcher Dr. Elizabeth Flesch Now Headed To Erebus Bay, Antarctica!

Weddell seal population project genomics researcher Dr. Elizabeth Flesch is now on her way to join the rest of the field team based at McMurdo Station, Antarctica. Elizabeth received her PhD from Montana State University, and works as a post-doctoral scholar with the Chen Lab and lead scientist and evolutionary biologist Dr. Nancy Chen, University of Rochester. Elizabeth is co-advised by Weddell population project lead scientist Dr. Jay Rotella. 

Elizabeth (she/her/hers) is interested in understanding how external forces influence population genetics across landscapes. She is using demographic and genomic methods to evaluate the spatial scale of dispersal and gene flow among breeding colonies of Weddell seals found in Antarctica. This approach will help identify potential drivers of temporal variation in immigration. Elizabeth earned her Ph.D. at Montana State University, where her dissertation addressed the population genomics of bighorn sheep in the Rocky Mountains. In her free time, she enjoys rock climbing, gardening, and hiking. (Photo and bio courtesy the PopGen Chen Lab website.)

The Principal Investigator on the Weddell seal population genomics research is Dr. Nancy Chen, Chen Lab, University of Rochester. This is a collaborative grant with the Weddell seal population project, funded by the National Science Foundation. 

Nancy (she/her/hers) is an evolutionary biologist interested in the genomic basis of contemporary evolution in natural populations. Her research integrates genomics and long-term demographic studies to characterize the evolutionary processes shaping patterns of variation across the genome through space and time. Nancy earned her Ph.D. with Andy Clark and John Fitzpatrick at Cornell University and then did a postdoc with Graham Coop at UC Davis before moving to Rochester. She is committed to promoting equity and inclusion in STEM. Nancy enjoys running, hiking, cooking, and playing board games. Photo and bio courtesy the PopGen Chen Lab website.

We look very much forward to Elizabeth's arrival on The Ice, and to delving deeper into this fascinating science work to better understand population genomics and immigration of the Weddell seals of Erebus Bay, Antarctica!

- Mary Lynn Price

2023 Mid-Season Field Report From Lead Scientist Dr. Jay Rotella

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.

Last Year's Oldest Weddell Mom Recorded Again This Season For New Records!

Special Field Report From Dr. Jay Rotella:

Yesterday, the team found 0550C, who during the 2022 field season tied the previous lifespan record at 32 years of age.  With her new sighting in 2023, she ties the record for lifespan at 33 years old and sets a new record for the number of pups produced in a lifetime at 24 pups (14 daughters and 10 sons). So far, she has 2 daughters that have survived and gone on to produce pups.

Photo by Parker Levinson of Rare Old Mom 0550C this season with her 24th Pup.

One of those daughters is now 24 years old and with her 10^th pup this year. Both the mother (0550C) and her 24-year-old daughter are at Hutton Cliffs this year and about 3 km from one another. The 24-year-old daughter has had 2 daughters and 1 of those has already had 2 female pups. So, 0550C has daughters and granddaughters.

Rare Old Mom 0550C as photographed by Parker Levinson last season with her 23rd Pup.

Two of her sons have been seen again in the study area; one of them, who was born in 2001 and is now 21 years old, was first seen again in 2010 as a 9-year-old and in 9 of the past 12 years: it’s possible that he is contributing to 0550C’s lineage.

Project video by Jeremy Schmidt and Jay Rotella showing the pupping history of a different Rare Old Mom.

Many of 0550C’s more recently produced offspring are too young for us to know how they will fare. However, given that less than 2% of mothers typically produce more than 7 pups in a lifetime, 0550C is at the high end of the productivity that’s possible in the species, which requires a long lifetime to achieve given that the females of the species can only produce 1 pup per year at most, except in the very rare case of twins. She is also a great reminder of just how long it takes to reveal information on lifespan, lifetime reproductive output, and family trees in a long-lived species.

- Dr. Jay Rotella, Weddell population project lead scientist

Oldest Weddell Mom Ever Recorded!

Field Report From Prof. Jay Rotella:

We have a new record for the oldest Weddell seal ever recorded. Our new record-setter is 33 years old and with her 21st pup. She broke the longest-known lifespan record by 1 year, and she’s just 1 pup short of tying the record for the most pups produced in a lifetime, which is 22. She’s also a great reminder of just how faithful many of the animals in our study population are to the Erebus Bay colonies.

This female, who’s currently wearing yellow tags numbered 8281, has been documented in the study area in 32 different years starting with 1990, the year she was born and first tagged. She has been in the study area in every pupping season from 1995 through 2023. That’s 29 years in a row and includes 1995-1997, when she was a pre-breeder, 1998 when she had her first pup, 20 other years when she had subsequent pups, and 5 years when she skipped reproducing. She is also interesting in another way.

She has produced 14 sons and 7 daughters, which is obviously not a 50:50 sex ratio for offspring that’s the population-level average. We have found that the mothers who are more productive do tend to produce a greater proportion of sons.The idea behind that being that if you are in great shape and can produce a high-quality son, he can go on to sire many pups in this species in which the top males can breed with multiple females and in which females produce at most a single pup per year except in the very rare cases when twins are produced.

A map of her annual locations shows that she has been quite faithful to the Hutton Cliffs area, which is where we tend to see most, but not all, of the supermoms and something we plan to look into further in the next few years. Many of her annual locations are so close to one another that the markers on the map tend to fall on top of one another, which is why you don’t see all 29 locations on the map at the resolution of the image provided.

- Dr. Jay Rotella

Fun New Short Video By Writer and Imager Jeremy Schmidt!

Weddell seal population project multimedia specialist Jeremy Schmidt's newest short-short video creation Cold Comfort shows us some of the challenges and joys of studying Weddell seals in Antarctica.

Jeremy is a wildlife and adventure travel writer and imager. He is the author and creator of the project's new multimedia ebook Weddell Seals, now available FREE on Apple Books, Google Play Books, and as a direct download on our WeddellSealScience.com eBook page.

He is also the co-producer of our most complete project science video to date, How Moms Matter To Weddell Seal Pups. This 14 minute short film is an Official Selection at the 2024 Wildlife Conservation Film Festival to be held in Naples, Florida this coming January.

Some of Jeremy's other fun short-short videos can be viewed in a previous field blog post, Five Short Videos By Jeremy Schmidt.

- Mary Lynn Price

Fascinating Paper Published On Weddell Seal Population Dynamics

Weddell seal population project PhD student Kaitlin Macdonald is the lead author of a fascinating recent paper published by the project in the Journal of Animal Ecology. The paper is titled, "Evaluating the importance of individual heterogeneity in reproduction to Weddell seal population dynamics using integral projection models." The entire paper is available Here.

Kaitlin and the paper's co-author Prof. Jay Rotella discuss the findings in this recent paper, and the importance of long term population studies, in our latest Weddell Seal Science Audio Podcast. The podcast is available through Apple Podcasts and Spotify. We hope you enjoy the new audio podcast episode, presented below!

- Mary Lynn Price