8 December, 2000
FYI answer for 12/07/00
The ratio of male to female pups born in a season is 50:50. However, most pups born early in the season are male, and more females are born in the latter part of the birthing season. This year in the study area, there were 475 pups born; 240 females, 235 males and three unknowns (these were pups that died right after birth).
Today marks one month that I have been living out here at the Big Razorback field camp. I have had a chance to do so many things and learn an extensive amount of information. I can add the activities and work from today to that ever-growing list. All seven of us boarded a Bell 212 helicopter, at 10:30 a.m. here at Big Razorback, after receiving the protocol for entering, exiting, and traveling on the helicopter. I have never been in a helicopter or ridden on one.
We first flew over the entire study area of our project. It was a chance for me to see just how the seals are spread out over these 85 square miles. We then flew to White Island, which is an isolated Weddell seal colony. These seals are thought to have traveled to this area when part of the permanent ice shelf broke off and then were trapped as the ice shelf closed off their entrance by reforming. The colony cannot swim under water long enough to get out, so they have lived around the water and ice cracks at White Island for at least 40 and as many as 90 years. This is, of course, a scientific study to find answers to these questions and see what the inter-breeding and isolation has done to this small population. We had three new pups that were tagged at this location and we recorded the already tagged females. There were about ten animals in all that we saw on the ice.
Our study area is inside Erebus Bay, along the coast of Ross Island, but our next stops were at colonies along the coastof the actual continent. Mike Cameron is interested in whether seals from these outer colonies immigrate to (move into) or emmigrate (move out of) from Erebus Bay. Because Weddell seals generally return to (or close to) the same location as the previous year, and because the continental coast is more than 30 miles from Erebus Bay, he believes that there should be very little movement between the areas. He is testing this by conducting censuses of both areas and by collecting tissue samples for a DNA study to determine if the two groups are genetically distinct. We had to find six more adult males to tag and take tissue samples from to complete the minimum requirements of the genetic tests. It is not just being able to go and tag a seal or take its tissue sample. There are very strict guidelines to follow with anything you do here.
Mike, Gifford, and I all worked together today whenever we landed and walked from group to group. Our last ground stop was at a place called the Bay of Sails, a frozen bay full of stranded icebergs. They were enormous and scattered within a half kilometer of each other. We censused a crack between three of them in the hour we were there. I got to retag two animals at this location.
The journey ended with a spectacular flight over the sea ice edge. This is where the ice is breaking and large flat sections are floating and eventually breaking up in the warming ocean waters. I saw Adelie penguins and Emperor penguins all over the ice edge. There was also a number of killer whales right off the ice edge. Of course, we also saw the Weddell seals. We flew the ice edge back towards Cape Royds--that's were the Adelie rookery and Shackleton's hut are found--then we continued over the Barnes Glacier and Cape Evans--where Scott's hut is found--and back to Big Razorback Island. I saw very large numbers of seals along each of these areas. It was a very unique day with fun, work, and science research all rolled into one.
The Weddell seal pups are born from mid-October to early Novmber Their average birth weight is 27 to 30 kilograms (60 lbs.) and they are around a meter in length. They begin to enter the water and swim after about 2-3 weeks, and begin molting (losing their "lanugo" or puppy-fur) after about 4 weeks, and nurse until the mother leaves in early/mid-December.
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