Weddell Seal Science

It's A Wrap–2016 Erebus Bay Weddell Seal Pupping Season A Success!

Special from Kaitlin Macdonald:

Our 2016 field season has concluded and our team has made it back to Christchurch. We had a very successful season full of new and exciting changes from my previous seasons on the ice. The sea ice edge was approximately 50 miles from our sea ice camp, much further than previous years. While the sea ice edge may have been much further than usual our team still spotted three different bird species, crabeater seals, both emperor and Adélie penguins in the study area. Our crew did an impressive amount of work this season.

The 2016 field season statistics:

• 131 pups were enrolled in our mass study
• The combined weight of seal pups weighed over the course of the season was 46,898 lbs.
• Our crew tagged 493 pups born into the Erebus Bay study area
• We obtained records of time spent in water from birth to end of lactation for 112 pups
• We carried out 6 surveys of our study area with a maximum of 933 tagged individuals counted during any one survey
• The crew obtained mass assessment photographs for 57 individual mothers
• We tagged 5 new pups at White Island

We were lucky to finish out the field season with PI Jay Rotella who joined us for our last few weeks weighing pups, photographing mothers and tagging adults. I am proud of the work we accomplished this season and our incredible crew! 

The 2016 field crew with Jay Rotella surveying for tagged seals outside the study area.

- Kaitlin Macdonald

 

Season Update 2 By Kaitlin Macdonald

- Kaitlin Macdonald

This Weddell Seal Mom is Golden!

Her name in the nearly 50 year old database of the Weddell seal population study is SPENO 9622. Let's call her Golden. She is the 25 year old daughter of the Rare Old Mom we've been reporting on for the past several years.

The top photo shows Golden (SPENO 9926) this pupping season with her very recently born pup. The second photo shows her and her plump pup later in the season. Note Golden's light brown coat.

Rare Old Mom's last re-sighting was in 2014 when she was 31 years old in the company of her 22nd pup. She is currently presumed to be deceased because she has not been re-sighted this season nor last season. Learn more about her amazing long life, history, and birth site fidelity from one of our past posts about her. 

Daughter Golden, SPENO 9926, likely has the benefit of great genetics and great nurturing from her extremely successful, highly productive and very long-lived Mom. Here is a graphic showing daughter Golden's re-sight and pupping history, courtesy of project lead scientist Dr. Jay Rotella:

In the graphic above are listed all of the pups of 25 year old Golden Mom during her lifetime (not including her newest pup this season). Weddell seal moms live an average of 15 years, and usually have around 2 pups every 3 years, so this long life and number of pups is unusual. Of Golden's 16 pups to date, 4 have been re-sighted in subsequent years, and two have had pups of their own. 

Note that Golden's pup born in 2000, SPENO 14465, has now had 6 pups, herself, for a total of 7 grand-pups for Golden, and 7 great grand-pups for the Rare Old Mom from Golden. Weddell population project scientists are studying the relationship of maternal effects and pup survival and recruitment (joining a pupping colony and having a pup). Having a nearly 50 year database of Erebus Bay Weddell seals gives scientists a unique opportunity to more closely study maternal effects, pup survival to recruitment, and heritability of these effects. It will be fascinating to learn more over the next several seasons about how maternal effects relate to this lineage of Golden and the Rare Old Mom.

- Mary Lynn Price

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Weddell Pupping Season Update, Last of Study Area Pups Tagged!

Weddell seal population study lead scientist Dr. Jay Rotella reports from the ice: "Our 2016 field season continues to go very well. The last few pups of the 2016 season were born about 10 days ago, and we have now tagged all pups born in the study area.

Mom and pup lounge on the sea ice at the Hutton Cliffs Weddell seal pupping colony, the largest of the pupping colonies in the Erebus Bay Weddell seal population study area. The mom is SPENO 9926 with her 16th pup lounging on the sea ice at Hutton Cliffs. This seal mom is 25 years old, and is the daughter of the oldest Weddell mom having had the most pups over her lifetime ever documented in the nearly 50 year study of the Erebus Bay Weddell seals.

"The number of pups this year is slightly above the long-term average over the past several decades. Our research team has now completed 5 of 7 population surveys and has only 1 week of field work left. Although pup numbers are slightly above average, the numbers of (1) females without pups and (2) males appear to be lower than what has been observed since the iceberg years of 2002-2006.

The Weddell seal pupping colony at Big Razorback Island, with Little Razorback Island in the background on the left and Mt. Erebus rising above all in the center. Iconic Mt. Erebus is the southernmost active volcano on Earth.

"The fact that pup production remains above average while the overall population appears to be lower than typical in a year when the ice edge is farther north provides an interesting data point on factors hypothesized to be related to the population’s dynamics in the multi-decadal time series for the Erebus Bay population."

A very skinny Weddell mom with her now hefty pup. Weddell moms can lose roughly half their body weight during the pup nursing period, transfering all that energy to their ever-growing pups in the form of thick, rich milk.

- Jay Rotella

Many Great Ways To Stay in Touch with the Weddell Seal Population Project!

Once the Erebus Bay Weddell seal pupping season begins during the Antarctic Spring, and the research field team heads to Antarctica, we start up the Weddell Seal Science Antarctica field blog. We've been doing this every year since 2010.

After the Erebus Bay Weddell seal pupping season ends and the field team returns home, we continue to keep viewers posted on project updates and relevant news via our several social media outlets. Viewers can find links to most everything Weddell project-related, including links to all the project's published papers, and all our social media links, at our project web portal, WeddellSealScience.com:

Check out our Instagram photos and accompanying narrative captions. The photos are beautiful, and often available only through our Instagram page, which is produced by lead scientist Dr. Jay Rotella and his daughter, Sophie Rotella. Please Follow us on Instagram!

Our Weddell Seal Science Facebook Page is a good source of updates, news, and information about the Erebus Bay Weddell Seal Population Study. Please like us on Facebook!

We are present on Twitter via our Weddell Seal Science Twitter Page. Please Follow us on Twitter!

Our Weddell Seal Science YouTube Channel includes nearly all our Weddell Seal Project videos over the past several years. Please check out some of our videos and leave feedback!

We have a Weddell Seal Science Video Podcast available at iTunes where you can view some of our project videos:

A selection of Weddell Seal Project videos can be found on Google Earth's 'Explore the Ocean' Layer, courtesy of Mission Blue. To access these videos embedded in situ, download Google Earth, then launch it on your computer or mobile android device. Make visible the 'Explore the Ocean' Layer. Zoom in on Ross Island, Antarctica and note the small gold circles in the Erebus Bay study area. Cursor over each small gold circle to reveal the video embedded there:

The Erebus Bay Weddell Seal Population Study is funded by the National Science Foundation, with support from the U.S. Antarctic Program. The Principal Investigators on the project are Drs. Jay Rotella and Bob Garrott of Montana State University-Bozeman Ecology Department, and Dr. Don Siniff, Professor Emeritus at the University of Minnesota.

- Mary Lynn Price
Weddell seal project multimedia specialist

Weddell Seal Science Videos Now Available at the National Science Digital Library (NSDL)

The Erebus Bay Weddell Seal population study is excited to announce that we now have a good selection of Weddell seal population study videos and our public outreach and education WeddellSealScience.com web portal available through the National Science Digital Library (NSDL) website. The videos are available as Open Educational Resources Commons products allowing video download and educational usage.

To readily get to our products at the NSDL, go to their easy-to-use website and type "Weddell Seal Science" in the main Search field to access, watch, and download our project videos. Viewers can check out and download videos for personal enjoyment and informal science learning and teaching. The videos can be remixed to create new educational products. 

Following is the description of the mission of the National Science Digital Library from their "Overview" section:

Who We Are and What We Do

The National Science Digital Library provides high quality online educational resources for teaching and learning, with current emphasis on the sciences, technology, engineering, and mathematics (STEM) disciplines—both formal and informal, institutional and individual, in local, state, national, and international educational settings. The NSDL collection contains structured descriptive information (metadata) about web-based educational resources held on other sites by their providers. These providers have contribute this metadata to NSDL for organized search and open access to educational resources via this website and its services.

Most resources in the library adhere to principles of Open Educational Resource (OER) access, although some resources are restricted to provider site membership, or may have a cost associated with them (indicated in the full record of the resource).

All WeddellSealScience.com videos and products are free for educational usage! We hope you enjoy watching some of our videos and accessing our web portal, WeddellSealScience.com!

- Mary Lynn Price

 

Animal Neighbors of the Erebus Bay Weddell Seals

During the Weddell seal pupping season in Erebus Bay, Weddell seals can be sighted in pupping colonies scattered throughout the study area. But they are not the only animal species encountered on top of the sea ice in this part of Antarctica. Their animal neighbors can include crabeater seals, emperor penguins, Adélie penguins, south polar skuas, kelp gulls, and snow petrals. 

These two photos show a Weddell seal pup, Leptonychotes weddellii, on top of the ice and breathing at the surface of the icy Antarctic water. Weddells are true seals of the family Phocidae, and spend their entire lives in Antarctica. They are the southernmost breeding population of mammals on Earth, and can be found all around the coast of Antarctica.

Below is a crabeater seal, Lobodon carcinophaga, lounging on the ice near a Weddell seal. Crabeater seals are thought to be the most abundant seals on Earth, and are true seals that can be found all around the coast of Antarctica. They feed primarily on Antarctic krill, and have specialized teeth to assist them in straining krill from the water.

Among the bird species found in the Erebus Bay Weddell seal study area is the kelp gull, Larus dominicanus, a big gull of the Southern Hemisphere as seen in the photo below.

The south polar skua, Stercorarius maccormicki, in the photo below, is a large predatory bird that feeds on fish often stolen from other birds. This bird can often be seen feeding on Weddell seal birth placenta in the pupping colonies.

Emperor penguins, Aptenodytes forsteri, are the tallest and the heaviest of the penguin species and can dive deeper and longer than any other penguin. They breed in large colonies and are often seen in small groups traveling through the Weddell seal study area.

The smaller Adélie penguin, Pygoscelis adeliae, as seen in the photo below, also form large colonies around the coast of Antarctica. These birds can often be seen singly or in small groups traveling about the Erebus Bay Weddell seal study area.

- Mary Lynn Price

Update From The Ice!

So far, this has been a very interesting pupping season for the Weddell seals of Erebus Bay, Antarctica, and the Weddell population study's research field team. There is change this year in both the number of pups born in the study area compared to the past few years, and the location of the sea ice edge this pupping season.

Project lead scientist Dr. Jay Rotella notes, "All continues to go very well with the 2016 season. Most of the pups for the 2016 season have now been born. It appears that the number of pups this year will be quite close to the long-term average. The team has identified and tagged over 400 pups and completed the 1st survey of the population. They will try to obtain 6 surveys between now and Dec 8th to obtain data on the size of the population that’s using the study area this year and to assess the composition of the population." In comparison, last season there were 658 Weddell pups born in the study area.

As for the sea ice edge just beyond the study area, Rotella notes that, "The ice edge is farther north this year than it’s been in recent years. Given that, it will be interesting to see how the numbers of pups and adults that are seen this year compares with what has been seen in other years."

Below are two Sea Ice Maps courtesy Brad Herried of the Polar Geospatial Center (PGS). The maps show in the upper right area where the sea ice edge is this season. In the top map for this year, no sea ice edge can be seen because it is further north beyond the map area. In the 2nd Sea Ice Map from around this same time of year in 2015. In start contrast to this year, the sea ice extent was much further south in McMurdo Sound, and much closer to the study area pupping colonies. Sea ice extent affects the distance the Weddell seals must swim initially to get to the pupping colonies, and how much distance there is between the seals and their predators beyond the sea ice edge. Sea ice extent can also affect how much bio-production is going on under the ice, and how much in the way of food resources might be available for the seals.

Says Rotella, "In addition to understanding the lives of individual seals, the project also seeks to understand how population size and structure varies with environmental conditions. Thus, obtaining data from years with differing conditions is vital, and years such as this are very interesting and help greatly."

In another interesting update from the research field team on the ice, a crabeater seal is photographed lounging on the ice next to a Weddell seal. Crabeater seals are occasionally seen in the study area, and are one of the 4 species of seals that live their entire lives in Antarctica, including the Weddell seal, the Ross seal, and the leopard seal. See if you can spot the differences between the crabeater and the Weddell seal!

- Mary Lynn Price

Pupping Peaks, Team Work Continues

The Antarctica field team is now shifting gears in their field work. Weddell seal pupping has peaked, and the field work is now focusing more on population surveys, and assessing seal mom and pup weights. The number of pups born in the Erebus Bay study area appears to be down some from the last few years when record high numbers of pups were born during the pupping seasons. 

Last season, some 658 pups were born--one of the highest pupping numbers ever for the nearly 50 year old Weddell seal population study. This season the number will be lower. Lead scientist Dr. Jay Rotella, who will soon join Dr. Bob Garrott and the rest of the field team on the ice, noted in a previous post that, "Since 2004, annual population sizes and pup-production levels have ranged from record lows (in 2004, only 169 pups were produced, which is 38% of the long-term average) to the highest level recorded since 1967 (in 2015, 658 pups were produced, which is 149% of the long-term average)."

With the shift in focus at this point in the season, the field team will be conducting more Weddell seal population surveys, and seeking out pups and moms weighed this season to reweigh them at subsequent points during the pup nursing/nurturing period. 

To conduct Weddell seal population surveys, the field team will travel over the entirety of the Erebus Bay Weddell study area counting and identifying every seal. The team will do this between 5 and 8 times over the duration of the pupping and nurturing period in order to account for all the seals that may be in the water on a single survey, maximizing the number of individual seals counted through repeated census surveys.

We'll have further data from the team as the season progresses in November.

-Mary Lynn
 

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-Mary Lynn Price