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“That included the total number of lions killed, the number that were wearing functioning tracking collars (35) during the season and the number of lions wearing those collars (11) that were turned in by hunters.”

For the mark-recapture method mentioned in this article to be valid, those “Marks” have to be added to a closed population, where no new individuals are added.  Collars (marks) were added several years ago and every year they continue to use them to estimate the population based on how many collars are returned.  The idea behind mark and recapture is that the number of marked animals returned (11) to the number of total animals returned (73 Killed) is proportional to the number of total marked animals (35) related to the total population X.  (73/11 = x/35) (x being the ORIGINAL size of the population when you marked the animals).  However, IF more individuals(kittens) are added to the population since the marking, then it throws off the proportions and will actually result in higher estimates.  In fact, as fewer animals are marked (now there are only 24), this also inflates the numbers, e.g. if they kill 100 animals and again only 8 of them are marked, this will give them an even larger population estimate after the hunt.

The way they are using this technique, the fewer collared animals remain and the higher the kill level, the greater the population size is – a blatant abuse of a dubious estimation technique!   

http://rapidcityjournal.com/news/a-record-year-for-lion-deaths/article_10e36dba-4f45-5670-ad45-319c3b5d832c.html

Kevin Woster Journal staff

When a state Game, Fish & Parks Department officer killed a 9-month-old mountain lion in Spearfish last Sunday, it was the 96th confirmed lion mortality this year.

That is already a yearly record in GF&P lion statistics, with more than four months to go in 2012.

And if confirmed lion deaths continue as they did in 2011, the 2012 total is likely to be between 115 and 120 for the year.

Read more…

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