In exciting news from the ice, one of the daughters of the Rare Old Weddell Mom we've been reporting on for several years has been encountered at the Hutton Cliffs Weddell pupping colony!
In a field blog post back in 2012 we reported that the field team had encountered a very rare old mom, then with her 20th pup. The Old Mom's age was 29 years at the time, and her identification was SPENO 5970. We could track her age, locations, and pups back through the years, as well as what some of her pups went on to do. One of her female pups was encountered as an adult with her own pup by the field research team in 2013: SPENO 9926, wearing the tag 8731A. We lost sight of the rare old mom this past year, which likely means she didn't survive to return this past season. And she has not yet been encountered this season.
However, Daughter SPENO 9926, of the Rare Old Mom has been re-sighted this season!
Here are project photos by Ph.D. Student Terrill Paterson of Daughter SPENO 9926 with her pup from back in 2013...
The project was fortunate enough to follow part of the amazing long life of Rare Old Mom SPENO 5970 over the past several years. Here's a photo by Dr. Jay Rotella of her in 2014. She was then 31 years old and had with her her 22nd pup. This was the last year she was sighted by the field team.
According to lead project scientist Jay Rotella, what was so remarkable about this Weddell mom is that she had 22 total pups over a 31 year life. She produced pups at ages 8, 9, 10, (3 in a row then 1 year off), 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, (16 in a row then 2 years off) 29, 30, 31, (3 in a row for the 3 most recent years). Weddell seal moms live an average of 15 years, and usually have around 2 pups every 3 years, so this long life and frequency of pupping is very unusual.
All of the pups of SPENO 5970 were born at Hutton Cliffs. For the past several years Hutton Cliffs had been a rugged area with jumbled multi-year ice, hummocks, and rough sastrugi. However, the past couple of years the ice has been smooth 1st year ice; and much of the Hutton Cliffs seal colony can be seen for some distance on the flat terrain in the photo by Dr. Jay Rotella.
Rare Old Mom SPENO 5970 was born in 1983 at an area called the North Base of the Erebus Glacier Tongue. This area is relatively close to the Hutton Cliffs pupping colony, where all of this Weddell mom's 22 pups have been born over her reproductive life to date. It is also where her pup, Daughter SPENO 9926A, was encountered this season!
Because of the longterm dataset of the Weddell seal population project, the researchers are able to keep track of the Weddells in the study area and access data on nearly five decades of seals and several generations.
Working with the extensive database, lead population study scientist Jay Rotella was able to determine that of SPENO 5970's first 21 pups, 11 were females and 10 were males. "Of those offspring, 2 sons and 2 daughters have been seen again, which is right in line with what we'd expect based on other analyses indicating that roughly 20% of the seals make it to adulthood." Her last pup born in 2014 was a female.
In the above photo from 2013 by project scientist Dr. Bob Garrott, Dr. Thierry Chambert is adding a tag to Rare Old Mom's 21st pup as the old seal mom quietly looks on.
Of SPENO 5970's surviving offspring, two daughters have returned to the pupping colonies to give birth themselves.
- Mary Lynn Price