A friend of mine called the other day to tell me he liked the new Weddell seal video. He also said he wondered, though, just why it is that these particular Antarctic seals are the focus of our study. After all, he asked, why can't all this population stuff be studied just as thoroughly by working with seals that live closer to home--like the harbor seals that congregate down at our local breakwater?
As I began to think more about what he said, I realized that he was asking a very good question--why is it so important to study these particular Weddell seals?
So here it is: A list of 10 top reasons why it's important to study these Weddell seals of Erebus Bay in Antarctica:
Reason #10. This group of Weddell seals in the Erebus Bay area of Antarctica's Ross Sea is a healthy, stable population of high level marine predators. So it's kind of like being able to study a healthy patient if you're a doctor--it helps you to better understand how a healthy population of long-lived mammals works in order to better understand and manage other long-lived species that are endangered or aren't doing as well.
Reason #9. This stable population of long-lived mammals lives its entire life in the most pristine marine environment left on Earth. So this is a rare opportunity to study a healthy population of marine predators that is currently functioning well in a healthy marine environment--and in so doing gain a better understanding of healthy interaction in a healthy ecosystem.
Reason #8. This stable population of Weddell seals, however, is living in a nearly pristine marine environment that is just beginning to experience potentially problematic environmental changes--both natural and man-made--climate change, increased ocean acidification, and possibly an increasing occurrence of extreme environmental events, such as more frequent calving of giant icebergs. These seals can act as a bellwether of the kinds of effects such environmental changes can have on a previously healthy marine mammal population.
Reason #7. These Weddell seals are a high level marine predator that are part of a currently intact food web, but that food web is just beginning to experience measurable changes possibly related to unregulated or under-regulated commercial fishing pressure on Antarctic Toothfish, krill, and other commercially harvestable marine life in the Southern Ocean. These seals can act as a bellwether of the kinds of effects such changes in the food web and in marine resources can have on a previously healthy marine mammal population.
Reason #6. Located very near the main U.S. Antarctic base, McMurdo Station, this population of Weddell seals provides researchers relatively easy access using surface vehicles based at McMurdo Station, with an entire support system in place to ensure vital science support to the researchers.
Reason #5. Tending to be fairly docile toward researchers, these Weddell seals are relatively easy to approach for scientific observation and interaction. This is likely because Weddells do not have a long history of dealing with natural predators on the sea ice during the Austral spring.
Reason #4. These Weddell seals are "philopatric" meaning they tend to return to the same areas where they were born to have their own pups. So even though there is some limited immigration and emigration of seals into and out of the established pupping colonies, for the most part this is a fairly closed and stable population, with predictable pupping colony sites.
Reason #3. The moms and pups are easily detected on top of the sea ice for the first week or so after the pups are born and before they learn to swim because they must remain on the surface, where they are particularly visible and accessible to the researchers.
Reason #2. Because of this ease of access, this particular population of Weddell seals has been studied for nearly half a century (>45 years), and an extensive database has been developed during that time that includes information on thousands of mom/pup pairs over several generations.
Reason #1. This longterm population database of a long-lived mammal studied intensively over generations spanning decades is unique in the scientific community, and provides scientists with a dataset that makes possible innovative ecological discoveries as the fields of population modeling and statistical methodology continue to advance.
Oh, and this top ten list doesn't even mention that these amazing animals are the southernmost mammal on Earth! That they are fantastic divers that travel further under the sea ice than any other animal on our planet to birth their pups safely away from other large predators. And that they spend a lot of time nurturing their young and likely passing on valuable survival skills during the nursing period!