One thing I always find sketchy about ecology are the population estimates for various species which can’t be tracked easily (under the sea, in the forests, etc.). In the end, I agree that there have be some aproximations, and they might be the best numbers we can come up with at any given time, but when those numbers are brandished in public policy discussions as definitive and established I get a bit nervous. In any case, I found this news reported in Scientific American very interesting, because it indicates that past estimates of baleen whale populations (on the order of 50,000 or so) prior to their decimation might be wrong, insofar as they do not suffice to account for the genetic diversity found in present whale populations. In fact, the estimates of wild whale populations prior to the 19th & 20th century drives toward extinction might be off by an order of magnitude, think 500,000 rather than 50,000. Still, this is an estimate, but genes have no great reason to lie or be biased in any way. Of course the best solution is to come to the same number from various vantage points. Finally, I am a bit curious as to possible ramifications this might have on our conception of the marine ecology as a whole, as some ecologists assert that penguins and other krill consuming species have benifited from the decline in whale populations. An examination of penguin DNA should indicate a rapid population expansion in the recent past. One implication of this sort of thinking is that the ecosystem has perhaps requilibrated (a higher portion of the biomass being penguins rather than baleen whales) and humpbacks and their cousins have too much avian competition to reach their old numbers again.
Here are more stories on this issue (not much more red meat than what you’d find in Scientific American though).
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