Now in high gear, the Weddell seal population study field team is setting up their remote sea ice camp, continuing to flag safe routes over the sea ice to the various pupping colonies, and tagging new pups born this season in the Erebus Bay study area.
The field team will also be conducting a series of census surveys of the entire Weddell seal population in the Erebus Bay study area to determine how many seals are present this season. Efforts to weight a select number of pups and moms for the project's mass dynamics study will be limited this season, however, because of the shortened time that the team will have on the ice during the critical period of the pupping season due to the government shutdown and field season delay.
The tagging of Weddell seals is central to this long-running population study. This season, the primary focus of the field team will be tagging all of the newborn pups in the study area. Previously untagged Weddell moms are also tagged, and seals with broken or misssing tags are retagged.
Tagging Weddell seals has been part of this project since its very beginning. The history of this project began with the initial tagging efforts of Dr. Ian Stirling in 1963, which were continued by Dr. Don Siniff and others from the University of Minnesota beginning in 1968.
The photo above is from 1973. From left to right in the top row are Don Siniff, Bob Hofman, Doug DeMaster, Dick Reichle, and kneeling from left to right are Ron Kirby and Ian Stirling. All of these individuals have gone on to have successful careers in various fields of ecology. Photo courtesy Don Siniff's Weddell project archive.
In 2002, the Weddell project moved to Montana State University with Drs. Jay Rotella and Bob Garrott as Co-Principal Investigators, along with Dr. Don Siniff (Professor Emeritus, University of Minnesota) who has continued as Co-Principal Investigator on the project. Bob Garrott initially worked on the project as a graduate student of Don Siniff, then would go on to become a Principal Investigator on the project some years later. So this long-term population project represents not only multiple generations of Weddell seals, but also generations of ecologists! For much more on the history of the Erebus Bay Weddell seal population study, please visit our WeddellSealScience.com History section.
Over the decades, a variety of different shapes and sizes of tags have been used in the Weddell seal population project, the most recent tag being the small plastic cyan-colored tag seen in the lower right hand of the photo below. More historical info on these tags is available as part of the Weddell seal database download available here.
The purpose of tagging these Weddell seals is to establish and record the birth date, birth location, gender, and identity of the mother of a newborn seal using a small plastic uniquely numbered tag that is affixed to the rear flipper of the seal. This information is recorded in the extensive database maintained by the B-009 population study since 1969. Data are available for download here. To date, approximately 22,000 Weddell seals have been identified and tagged over the life of this study in the Erebus Bay area.
Weddell seals are "philopatric", meaning they show strong fidelity to the areas of their birth, returning to these same areas to give birth themselves. This life history characteristic is what allows the scientists to develop extended reproductive histories of thousands of Weddell females. The researchers know when these seals were born, where they were born, how many pups they have had over their lifetimes and, in many cases, whether those pups survived to have pups of their own.
Because Weddell seals are long-lived mammals and don't start to reproduce until they are around 5 to 7 years old, this kind of extremely valuable multi-generation database requires decades to develop. Here's a brief project video about Weddell seals...