Weddell Seal Science

A Gracious Bravo! To The 2020 Weddell Seal Field Team!

Special Report from 2020 Field Team Leader, Kaitlin MacDonald:

Our crew has now completed the 2020 field season and we are awaiting the arrival of a LC-130 cargo plane that will take us back to Christchurch and eventually our homes in the US.

This year was quite different from any of my previous for a number of reasons. Due to the pandemic reductions in personnel that were made across McMurdo station our crew was reduced to three people. This year we had unusual sea ice conditions with the ice edge basically ending at the Erebus Glacier Tongue. For our crew this meant no Big Razorback field camp and more importantly only helicopter access to the northside of our study area. During this unusual season we were able to get quite a bit done despite the challenges we faced.

If you’ve been following along this year you will know we set-up two emergency camps with tents, food and fuel in case we were stuck in poor weather on either side of our study area. On the North side of the study area this is where we would land and stage our snowmobiles. Our last few days on the sea ice were spent deconstructing these camps and getting the gear back to McMurdo.

One of our snowmobiles is rigged to be transported back to McMurdo

Our largest success this season was tagging pups in the study area. We were able to tag all pups that were safely accessible in our study area and make the association between pups and mothers for most pups that were tagged. We ended up tagging over 500 pups this year. This was an important task for our crew as it allows us to know whether a seal was born in the study area, provides us with ages of individuals, and allows us to record reproductive histories for adult females. 

Will and Parker prepare to tag a pup

This year we continued our mass dynamics work weighing a subset of mothers and pups. We also deployed temperature tags on the pups that we weighed. While we were able to get mid-lactation masses for nearly all pups enrolled, due to deteriorating sea ice conditions the sea ice was closed to travel, and we were unable to get weaning masses for the majority of pups.

A fully molted pup catches some zzz's at Hutton Cliffs

In addition to weighing pups and photographing mothers the latter half of our season was spent doing study area surveys and retagging individuals that were missing full tag sets. We were very happy to have the time to retag adults with less than full tag sets as this work will ensure that we continue to get individual data for these seals. Our study area wide surveys can be quite long days because we spend these days making sure we record the tag numbers of every seal that is accessible within the study area. With only three of us our study area wide surveys took a bit longer and the number completed was reduced from a normal year, but we were still able to get these valuable data. 

The 2020 crew at the end of our final survey (from left to right: Kaitlin, Parker, and Will).

Our crew had the great fortune to spot three of the iconic Antarctic species during our work on the sea ice. We spotted a number of Adélie penguins, a large group of emperor penguins, and a pair of snow petrels! 

Emperor penguins at North Base

While this year was one of the more unusual for B-009 we are grateful to have the opportunity to continue our long-term study this year. We are thankful to the contractors and support staff at McMurdo who worked so hard to make our field season a reality! We couldn’t have achieved as much as we did without the hard work of Parker and Will, who stepped up to the challenge as first year crew members making this season fun and successful!

- Kaitlin MacDonald

Unusual 2020 Weddell Seal Pupping Season Comes to an End

The sea ice of Erebus Bay, Antarctica near McMurdo Station is now closed to further sea ice travel due to large cracks developing in the sea ice. Fortunately the 2020 Weddell Seal Population and Mass Dynamics Study field team was able to retrieve vital seal recording and logging instruments, complete one last seal survey, and obtain weights on the last group of pups.

Photos, above, courtesy Natalie Brechtel and Ben Adkison of McMurdo Field Safety & Training, show changes in the crack in the sea ice near Turtle Rock one week apart.

We hope to post one last 2020 field update from the Weddell seal study field team soon, with further information on this season's Weddell population, and number of pups born.

- Mary Lynn Price

 

 

Wild 2020 Weddell Pupping Season Wrapping Up

Special from Kaitlin MacDonald, Field Team Leader:

Our field season has flown by and we have just a brief time left to finish out the season. Towards the end of October and early November our crew of three was busy tagging pups and enrolling mother-pup pairs in our mass study. More recently we have been weighing pups on the south side of the study area.  We spent the past few weeks getting 20-day weights of pups and taking photos of their mothers for mass estimates.

Photo of Our Field Team Courtesy Natalie Brechtel

We are just now working to get the third and final mass measurement of pups enrolled in our mass study. At 35-days old we weigh these pups to get an approximate weaning mass and remove the temperature tag that has been attached to the pup’s flipper since birth. These tags record the time and temperature and provide a record of when the pup was in the water.  There is incredible variation in the time pups first enter the water, 4 days old to 32 days old, and the amount of time pups spend in the water. Shane Petch who recently defended his master’s thesis did some interesting work with the amount of time pups spend in the water.

Mom and pup lounging in the sun at Hutton cliffs, photo by Parker Levinson

We also flew out to White Island to tag pups and do a survey of individuals at this small colony. One of the mothers we encountered at White Island was 29 years old. Since the oldest mother we have recorded is 31 years old it was quite exciting to see such an old mom at White Island and what looks to be her healthy pup.

- Kaitlin MacDonald

2020 Weddell Pupping Season Field Team Interview!

In this very unusual 2020 Weddell seal pupping season, the Antarctic Field Team took some time to do a cool brief interview at the Hutton Cliffs Weddell pupping colony. Hope you enjoy it!

This short video was produced on location by the 2020 Antarctica Field Team: crew leader Kaitlin MacDonald, and field team members Parker Levinson and Will McDonald. More information on the Weddell Seal Population and Mass Dynamics Project at WeddellSealScience.com.

- Mary Lynn Price

This Most Unusual Weddell Seal Pupping Season!

This has been probably the most unusual Weddell seal pupping season in the project's 51 year history. First, the lengthy quarantines the three person team went through to get to the Ice and keep Antarctica Covid-free. Then the closeness of the sea ice edge this season, which prevents vehicular travel north of the Erebus Glacier Tongue where numerous Weddell seal pupping colonies are located. (All photos by team member Will MacDonald.)

Notes lead project scientist Dr. Jay Rotella, "Our team is making the best of the season and collecting lots of useful data thanks to the great support from many people that work at McMurdo Station and from the National Science Foundation. Pups are being born at a rapid clip though that should start to slow down pretty dramatically in another week or so."

"For the next 6-7 weeks, the team will start to focus more of their time on population surveys. By mid-December, we’ll know a lot more about pup production and the size of the adult population size in this interesting year," reports Dr. Rotella.

-Mary Lynn Price

2020 Weddell Seal Pupping Season Underway!

Special from Crew Leader Kaitlin MacDonald

It has been a busy start to an interesting season. Our team of three has been working hard to prepare emergency caches on the sea ice and start tagging pups. 

Our emergency cache on the north side of the Erebus Glacier Tongue. Photo by Parker Levinson

The sea ice edge which currently runs from the Erebus Glacier Tongue up to Tent and Inaccessible islands prevents our team from driving to the north half of our study area. To access the north side of the study area we will be using helicopter support this year. Before we could start flagging routes and tagging pups in the northern and southern halves of our study area we had to set-up an emergency cache where we can hunker down if the weather deteriorates while we are working. We successfully set-up both our caches with the wonderful help of folks from McMurdo. These caches are well stocked and will be a cozy refuge should we ever need them.

We have also been hard at work getting caught up tagging the pups that were born before we were able to start day trips to the sea ice. Our team does their best to tag every pup at each colony every other day so that we can ensure the birthdate of a pup occurred during a 48-hour window.

Knowing a pup’s birthday within 48 hours of birth allows us to ask interesting questions such as whether pup birthdates are related to maternal age or mass loss of mothers during lactation. Tagging pups soon after they are born also allows us to more easily identify the mothers of pups as they are in very close contact during the first week or so after birth.

Weddell seals at Turtle Rock

It's difficult to say exactly how we are doing in terms of pup numbers compared to previous years because we have only been able to access two of the colonies at this point. I did compare numbers for Hutton and Turtle Rock from previous years and it looks like we are at a similar number of pups tagged by this point last year. Our next flight to the north side is Wednesday so hopefully we should get a better idea of actual pup numbers after that flight, although it might be later than that considering we will need to flag a route to the north side colonies on Wednesday.

- Kaitlin MacDonald

Antarctica Sea Ice Conditions Challenge the 2020 Field Team

The sea ice edge in Erebus Bay of the Ross Sea in Antarctica is much further south this season, running right up to the end of the Erebus Glacier Tongue, and cutting off vehicle access to the Weddell seal colonies beyond the Tongue in the Erebus Bay study area.

This means that access to many of the Weddell seal colonies in the study area will require travel by helicopter, since snowmobiles cannot safely cross the Erebus Glacier Tongue (EGT). In many recent previous seasons, the Weddell Seal Study field team would be based at a remote sea ice camp located at Big Razorback Island. However, this very unusual season there is no way to transport the sea ice camp huts beyond the EGT. Below is a photograph by Natalie Brechtel, the Sea Ice Point of Contact, of the south side of Big Razorback Island and the sea ice edge beyond:

Inaccessible Island is in the background. This season the sea ice presents uneven frozen terrain, and requires great care in traveling, especially in flat light. Our field team is very well-trained in sea ice safety and safe travel.

Below is an image from a previous season showing the location of many of the Weddell seal colonies, as well as the placement in many of the previous years of the remote sea ice camp of the Weddell seal study field team members.- Mary Lynn Price

2020 Antarctica Field Team Now On The Ice!

Following weeks of Covid-19 quarantines put in place by the U.S. Antarctic Program to keep Antarctica Covid-free, the 2020 Antarctica field team is now on the Ice at McMurdo Station! The three-person team arrived on a U.S. Air Force C-17 transport jet.

This unusual year the three-person team will be based at McMurdo Station, and will work in the Erebus Bay study area as weather permits to assess and record all the new pups born in the study area this season. This work will maintain the 51 year continuity of this Weddell Seal Population and Mass Dynamics Ecology Study, which is unique in the scientific community.

The Study Team in Antarctica this year consists of the following members:

Kaitlin Macdonald, Weddell seal research field team crew leader
Kaitlin Macdonald is a current MSU Ph.D. student being advised by Co-Principal Investigators and Montana State University-Bozeman Professors, Drs. Jay Rotella and Robert Garrott. Kaitlin is crew leader for the field crew. She has worked on Montana State University research projects since 2012 and joined the Weddell seal project in 2014. She is now in her 6th year on the Weddell seal project. Kaitlin has also done field work with mountain ungulates and small mammals. She received her M.S. in Fish and Wildlife Management in 2018.

Parker Levinson, Weddell seal research field team
Parker received her bachelor's degree from Northwestern University in 2018, and has worked a variety of seasonal wildlife jobs from studying leatherback sea turtles in the tropics to Adélie penguins in the Antarctic. Originally from Monterey Peninsula, California, Parker enjoys hiking, photography, and reading in her spare time. 

Will McDonald, Weddell seal research field team
Will graduated from Montana State University with a bachelor’s degree in Organismal Biology. He has worked on numerous wildlife research projects, involving a diverse group of species including birds, mesocarnivores, ungulates, and large carnivores. Most recently, Will has been working on a bighorn sheep nutritional ecology project and serving as a statistical analyst/programmer for an environmental consulting firm back home in Wyoming. In his free time, Will enjoys biking, ceramics, and cooking a good meal. 


This season, the sea ice edge (where the ice ends and the sea begins) is quite close to the Weddell seal study area. Here is a photo of the sea ice edge behind Tent and Inaccessible Islands:

Please check back soon for updates on the team's work with the Weddell seals of Erebus Bay in the Ross Sea of Antarctica! Learn more about the study, the project, and the Weddell seals at WeddellSealScience.com.

- Mary Lynn Price

 

What A 2019 Weddell Seal Pupping Season!

Despite challenging sea ice conditions this year, it's been a productive and successful Weddell seal population study science season in Erebus Bay, Antarctica. Lead scientist Dr. Jay Rotella reports that "the population produced an above-average number of pups and we were very successful at obtaining body-mass dynamics information on a solid sample of mothers and pups at birth and during lactation."

 

The field research team also encountered a number of older Weddell moms with pups again this year, seals that have come to be know as "super moms" due to their unusually long lives and high number of pups birthed over their extended lifetimes. Here's the latest short project video produced by Jeremy Schmidt about Weddell Seal Super Moms:

Science work in the Erebus Bay study area this pupping season was made more challenging than usual for the field research team by the sea ice conditions. "Despite the ice being somewhat thinner and warmer than is typical, we were able to safely and successfully conduct all of our work", notes Rotella. "The main implications of the thinner ice had to do with the heavy equipment that hauls our four huts for our camp out to the sea ice early in the season and back to McMurdo at the end of our season."

"The ice thickness led to concerns for safely operating the heavy equipment. Thus, our field camp could only be on the sea ice for part of our field season. Fortunately, much of the new ice that was present this year allowed us to get our work done despite working from McMurdo Station (rather than our sea-ice camp) for the last portion of our season."

That science work consisted of locating all the new pups born in the study area, placing small unique identifying tags between their rear flippers, and adding info on those pups and their moms into the extensive multi-decade Weddell seal database. A select number of pups and moms had their mass (weight) assessed, with pups weighed at birth, in the middle of the approximately 45 day nursing period, and then again at the end of the nursing period. Some of those pups also received a small temporary tag to record how often and how long those pups spent in the water learning to swim and spending time close to their moms. The field research team also made several surveys of the entire study area to determine the total number of Weddell seals present this year.

With these data added to the extensive population database, project scientists are able to better understand how this population is faring, and make new discoveries about what characteristics of Weddell moms and pups are important to Weddell pup survival to adulthood and successful future reproduction. The scientists are also able to construct detailed genealogies for many of the seals studied year after year. And this information identifies Weddell seal super moms in the process!

Great work all! And a huge Thank You to the National Science Foundation, the United States Antarctic Program, and all the great support people at McMurdo Station! 

For more short articles on the science work of the project, what we've learned and how we've learned it, and these amazing Weddell seals, check out our collection of posts and articles, images and video on our Select Articles page of WeddellSealScience.com. We have lots of great images and info available on our Weddell Seal Science Instagram page, and many more videos on our Weddell Seal Science YouTube Channel!

- Mary Lynn Price

Part 4: "How Moms Matter To Weddell Seal Pups"

In Part Four of our longer project documentary "How Moms Matter To Weddell Seal Pups" the focus is on what project scientists are learning about Weddell pup birth timing during the pupping season. Are pups better off if they're born in the early part of the season, late in the season, or somewhere in the middle? How do differences in Weddell moms affect the time in the season when the pup is likely to be born? Turns out that the time during the season when a pup is born, and the age and experience of that pup's mom, can affect the pup's likelihood of survival to adulthood to have a pup of her own.

Weddell Seals Galumphing in Antarctica: New Short Video!

Weddell seals have developed many different fascinating adaptations for living and thriving in the cold icy environment of Antarctica. For example, they have evolved large strong sharp front teeth to use to rake the sea ice to enlarge and keep holes and cracks open so they can breath and access the surface of the sea ice. They also have developed the ability to hold their breath for over an hour to make long dives beneath the Antarctic sea ice.

These seals also have a special secret to getting around when they're on top of the sea ice! Here's the Weddell Seal Population Project's latest short-short video produced by Jeremy Schmidt that shows us how it's done!

- Mary Lynn Price

Update From the Ice: Sea Ice Camp Now Being Pulled

In keeping with the challenging sea ice conditions this season around McMurdo Station and the Weddell seal population study area of Erebus Bay, the project’s remote sea ice camp is now being pulled a few weeks earlier than in previous recent seasons. Reports lead scientist Jay Rotella, "We have had a very good year for pup production and other data collection." Sea ice camp this season had been placed at Turtle Rock nearer McMurdo due to this year's challenging sea ice conditions. Turtle Rock is located a good distance from some of the more remote pupping colonies the field team must access in the Erebus Bay study area to do their science work. For over a decade, camp has been placed at Big Razorback Island, further out in the study area and more central to many of the pupping colonies.

 

HDR photo of the study's Kitchen Hut at Big Razorback Island in 2010

The sea ice this season is thinner in places and can be more troublesome for heavy equipment now. Yet the field research team’s work gathering data on the seals throughout the study area continues! This work keeps intact a multi-generational Weddell seal database unique in the scientific community, and is made possible by the many hard hours put in by the field team and the dedicated assistance of many different groups and support personnel on the Ice.

 

There are a few later-season pup births still taking place, and numerous pups and moms that the research team must continue to follow until the nursing period is over. The field team will work from McMurdo Station now to continue to get into the field as safely and successfully as they are able to gather necessary data.

 

In Part 3 of our project’s longer video, “How Moms Matter To Weddell Pups”, the presentation focuses on what the scientists are learning about how differences among Weddell moms and pups may effect the pup's survival to adulthood. And particularly when it comes to when during the pupping season the pups are born, how much they weigh at birth, and then how much at weaning. It will be interesting to learn if and how the challenging sea ice conditions this season affect the survival to adulthood of this year’s cohort of pups!

- Mary Lynn Price

A Great Year for Weddell Seal Pups!

The Antarctica Weddell seal population study's remote sea ice camp is at Turtle Rock this year due in part to the sea ice conditions this season. Peak Weddell pupping season is now winding down. New pups will continue to be born for some time, but not at nearly the rate of peak season. Lead project scientist Montana State University professor Jay Rotella reports, "we don’t have internet [at our sea ice camp] and have been able to work each day without weather delays." While this has limited internet updates on the season as it has progressed, it has also allowed the field team to take full advantage of peak pupping time to get a lot of work done!

Since our last report from the ice, the field team has been able to get out into the field without substantial weather delays and put a lot of effort into finding and working with the seals in the Erebus Bay study area. Notes Rotella in his new update, "It looks to be another big year for pup production with over 500 pups [born] so far this year. It’s also a great year for getting data on time spent in water by pups and on weight gain and loss by pups and their mothers."

Here's an award winning project short video documentary that presents information on work done by the project on assessing Weddell seal pup time spent in the water. As scientists learn more every year about which pups actually survive to return as adults to have pups of their own, researchers will be able to better understand the relationship between pup time spent in the water learning to swim and other Weddell seal life skills, and Weddell pup survival to return as reproducing adults.

For viewers interested in watching stereo 3D videos, here's an award-winning project stereoscopic short documentary video on Weddell pup swimming behavior and survival. You'll need 3D glasses to get the stereoscopic effect...

- Mary Lynn Price

Differences Among Weddell Seals & What That Can Mean to Pup Survival

The Erebus Bay Antarctica Weddell seal pupping season is now at its peak. The field research team is currently working to find all the Weddell pups born in the study area to identify, tag, and add them to the over 50 year population database. The team is weighing a select group of pups and moms to determine their current weights, and measuring the time select pups spend in the water during the approximately month and a half long nursing period.

More on Weighing Weddell Seals Here

The field researchers must travel to all the different Weddell pupping colonies in the Erebus Bay study area to do their jobs. Their travel is usually by snowmobile. This season the sea ice has been interesting and a bit challenging, yet the field team carries on during what is a very busy Weddell pupping season! We'll update you with new pup numbers as soon as field team members can access the internet.

The project scientists are gathering data to learn the extent of differences--variation--among Weddell moms and pups. As more is learned about variation in these Weddell moms and pups, the scientists are able to gather data about how many pups with particular characteristics survive to adulthood to have pups of their own. Researchers can follow the generations of pups born to particular moms, and are assessing the contributions to the population of surviving pups. The scientists are thus able to learn more about which individual characteristics have significant effects on pup survival to reproduction.

In the following Part 2 segment from our latest project documentary, "How Moms Matter To Weddell Pups", the topic of Weddell seal variation is introduced. Subsequent segments from this original 14 minute project documentary highlight the effects that such differences among Weddell moms and pups can have as to whether a pup will survive to adulthood and reproduction, and which of those moms are so successful that they have numerous pups, some of which go on to also become very successful moms...Weddell seal super moms!

The entire 14 minute project documentary "How Moms Matter To Weddell Pups" can be viewed on our Weddell Seal Science YouTube Channel.

Below, is an earlier project documentary on Weddell seal variation, "Being Different if You're a Weddell Seal in Antarctica". This previous documentary goes into some detail about the kinds of variation among Weddell seals that the scientists are finding. The new documentary, "How Moms Matter To Weddell Pups", takes everything a step further by presenting some of what the scientists have learned to date about the effects on pup survival of particular characteristics among Weddell moms and pups. Here is that full video for a bit of background:

- Mary Lynn Price

Weddell Pup Life Lessons

Weddell seal pups spend around 6 weeks after birth with their moms nursing, gaining a lot of weight, learning to get in and out of the cold Antarctic water, learning to swim well, and learning about how best to survive to adulthood by watching their moms interact with other seals in the pupping colonies. Then at around 45 days, Weddell moms leave their pups to fend for themselves with what they've learned during the nursing period. Only some 20% of female Weddell pups will survive to adulthood to have pups of their own. Here's the latest short-short Weddell Seal Science project video by Jeremy Schmidt on "Pup Life Lessons":

It's peak Weddell seal pupping season around the pupping colonies in Erebus Bay, Antarctica right now. The Weddell seal population study field team is extremely busy finding, recording, and tagging all the new pups born in the study area. Field researchers are also busy determining how much time a selection of Weddell pups spends in the water during this first 45 days of life. The field team works throughout the pupping season to determine the mass (weight) of a select group of moms and pups with known ancestries. These pups will be weighed three times during the nursing season, once near birth, and then again at the mid-nursing period, and finally at 45 days near the very end of the nursing season right before their moms leave them to survive on their own. The scientists have learned that there is wide variation among Weddell pups in all these areas, including how old and experienced their moms are, at what point during the pupping season they are born, weight at birth, weight gained during the nursing period, and time spent in the water learning to swim well. These individual characteristics, the scientists are learning, affect the Weddell pups' chances of becoming one of those 20% of female pups to survive to adulthood and have pups of their own.

- Mary Lynn Price

Remote Sea Ice Camp Now In Place at "Turtle Rock"

Weddell seal population study lead scientist Professor Jay Rotella reports that the remote sea ice camp huts where he and the rest of the field research crew will live and work for the duration of the pupping season have now been towed out to a new location in Erebus Bay. This season camp has been set up near a small island named "Turtle Rock". In the graphic below, the names and locations of the various Weddell seal pupping colonies in the Erebus Bay study area are indicated, including Turtle Rock, which is underlined in red."The heavy equipment operators from McMurdo brought camp out on to the sea ice early this week. Camp consists of four huts. Our team moved in and camp will be fully stocked and occupied by the end of this week," notes Rotella.

Regarding current ice conditions, Rotella says "Sea ice in the study area for the 2019 field season is not quite as thick as it has been in recent years. Currently, the sea ice is approximately 140 cm thick and suitable for our daily work. The somewhat thinner ice presents some challenges for the heavy equipment that pulls our camp huts to and from McMurdo Station for the season. Because of that, we’ve set our camp up closer to McMurdo and south of the Erebus Glacier tongue for the 2019 season. Although that site is a bit less ideal for our daily commutes to the various pupping colonies, the season is going well."

As of today Rotella reports, "Our field team is in camp at Turtle Rock. I will join them this evening in time for the peak of pup births the next two weeks. The team has tagged approximately 115 pups so far and is doing really well. So far, it appears that this will be another big year [for pup birth numbers]. It will certainly be another interesting and productive year!"

In all but one of the past ten years plus of the 50 year Weddell seal population study Antarctic field research, the remote sea ice camp was set up near Big Razorback Island. In 2011, however, the sea ice conditions necessitated that the sea ice camp be placed just south of the Erebus Glacier tongue. In this season's Turtle Rock location, the camp may not have access to wireless internet connection as it did when near Big Razorback Island. This is because the Big Razorback location relies upon transmit equipment for wireless internet connection that reaches that location. We anticipate that field team members will be able to send out photos and updates during their brief visits to McMurdo Station throughout the pupping season. Doing science work in Antarctica definitely requires flexibility and creativity when it comes to weather and sea ice conditions!

- Mary Lynn Price

Weddell Seal Short Documentaries

In addition to this season's fun new short-short videos about Weddell seals and the work of the population ecology research team that studies these seals in Erebus Bay, Antarctica, the project has produced numerous short documentary style videos over the years. Many have been screened at film festivals and won awards around the world. Earlier this year the project completed production on its latest short documentary, "How Moms Matter To Weddell Seal Pups". This informative 14 minute short film was created by Jeremy Schmidt and Mary Lynn Price with project visual material contributed by numerous Antarctica Weddell seal population study field team members, project scientists, and McMurdo Station diving personnel.

The full version of this documentary is the current project Featured Video on the Weddell Seal Science YouTube Channel. Here is a brief sample of that new video, Part One of "How Moms Matter To Weddell Seal Pups":

- Mary Lynn Price

About Those Weddell Seals

Weddell seals are the southernmost breeding mammal on Earth, and are found only in Antartica. This fun new short-short video produced by Weddell seal population study multimedia creator and writer Jeremy Schmidt presents "Five Weddell Facts":

Weddell seals are magnificent divers. They can hold their breath for over an hour, and have been recorded diving over 2000 feet deep. This diving ability allows them to swim far beneath the sea ice to access the surface in remote pupping colonies to give birth and raise their pups without threat from natural predators such as Orca and leopard seals. Weddells access the surface through cracks in the sea ice to give birth on top of the ice. These cracks are often associated with the rise and fall of the ocean tides against the ice frozen to land masses and islands. The ice attached to these land masses is referred to as "fast ice" as it is where the tidal sea ice meets the ice frozen fast to the land masses. In this quick time lapse video the rising and falling of the ocean tides creates cracks in a Weddell seal pupping colony that allows the seals to access the ice surface and the cold sea water below:

It is estimated that there are approximately 800,000 Weddell seals surrounding the Antarctic continent. The Weddell seal population and mass dynamics study focuses on the Weddell seals that return each year to Erebus Bay near the U.S. Antarctic base, McMurdo Station on Ross Island. Erebus Bay is located in the McMurdo Sound area of the Ross Sea. These waters are the most pristine marine environment remaining on Earth.

Weddell seals are "philopatric", meaning they return to the areas of their own births to reproduce and have their pups. This characteristic allows the scientists to study a particular population of Weddell seals over the course of many years and several generations of seals. This Weddell seal population study has been ongoing for over 50 years, and has developed a longterm data set unique in the scientific community. By studying the individual differences of so many seals going back several generations, the project scientists are able to make discoveries as to which individual characteristic of those Weddell moms and pups have contributed to the survival of those pups to adulthood to have pups of their own.

In an upcoming post we'll go into more detail about the lives of Weddell seal moms and pups and the individual characteristics of these amazing polar marine predators that project scientists have learned are significant to likelihood of pup survival and reproduction.

- Mary Lynn Price

Antarctica Field Team's Hard Work On the Ice

This season's sea ice conditions are a bit unusual, even considering the year to year variation in Austral Spring sea ice conditions in the Erebus Bay Weddell seal study area. The Weddell seal population study field team spends a lot of time at the beginning of the field season assessing and flagging safe routes to the various seal pupping colonies. In this photo, "Kit and Victor are profiling a crack near Turtle Rock to see if it is a safe location to put in a road crossing," reports field crew leader Shane Petch.

When the field team encounters a crack in the sea ice they carefully dig around it to expose its extent. They use small drills to determine the sea ice thickness surrounding the crack. The U.S. Antarctica Program has very strict safety guidelines when it comes to assessing and crossing cracks in the sea ice. In appropriate places special bridges can even be set to allow safe crossing. 

Once the field team has carefully determined safe routes to the various seal pupping colonies, they will then flag the routes to ensure safe travel. These safe flagged routes will allow the team to access the pupping colonies to record, tag, and follow new pups born in the study area. The photo below is of the first Weddell seal pup born in the study area this season to be recorded along with its mom and given a unique identification tag.

Weddell moms will stay close to their pups throughout the approximately 45 day nursing period. Close contact, nursing, and nuzzling help the mom/pup pair bond during the early days of the new pup's life. More about the life and activities of Weddell moms and pups in a future post!

- Mary Lynn Price

2019 Antarctica Field Team With Much Work Ahead!

The 2019 Weddell seal population study Antarctica field team is now at McMurdo Station and working hard to complete safety training and prepare equipment for the upcoming field work on the sea ice, reports this season's field crew leader Shane Petch.

Below is the 2019 field team, from left to right: Holly Lance, Heather Brown, Victor Villalobos, Kit Cunningham, Shane Petch, and Brandon Davis. This photo was taken outside the U.S. Antarctica (New Zealand) headquarters in Christchurch, New Zealand shortly before their flight to McMurdo Station, Antarctica.

Once at McMurdo Station the field team lost no time in preparing their gear and supplies for the Weddell seal pupping season ahead. In the photos below members of the crew assemble the new small tags that will be used to identify the new pups born this season in the Erebus Bay study area. 

Numerous safety and education courses will be completed by the research team members before they head out onto the sea ice, including sea ice safety and environmental training, as well as snowmobile and Pisten Bully operation and maintenance training. 

Once training is complete, the team will begin investigating and flagging safe routes to the numerous Weddell seal pupping colonies spread throughout the Erebus Bay study area. They will also work to prepare and provision the wooden sea ice huts that will soon be pulled out onto the sea ice and set in place for the season to serve as the remote sea ice base camp for the entire team. More on this in future posts.

This looks to be a great season ahead!

- Mary Lynn Price