The Florida Wildlife Commission (FWC) claims that the Central Bear Management Units (BMUs) had about
1000 bears in 2002 and 1300 in 2014 (Table 1), a 30% increase.  FWC claims that there are now 550
bears in the North BMU (Table 1); but I don’t have figures for their abundance in 2002.  For the sake of
argument, let’s assume that the FWC is right and that bear abundance in the North has more than
doubled.  Assume 220 bears there in 2002.  That would be an increase from 1220 in 2002 to 1850 in 2014
for the Central and North BMUs combined.  That’s a gain of 630 (51.5%) bears over 12 years = 52.5
bears/yr (4.3%/yr as an arithmetic average and 3.5%/yr as a geometric average – as for compound interest
on a bank account).  

Table 1:  FWC’s figures for each huntable BMU. This assumes that each BMU subpopulation could grow at
20%/yr if there were no human-caused mortality, and that subtracting out the number of bears lost to non-
hunting human-caused mortality, yields the balance that could be harvested by hunters and thereby
stabilize population size.
________________________________________________________________________________
     20% of             Average                
BMU                                         Population        Population        Known        Harvest               %
(Yr of Population Estimate)        Estimate           Estimate        Mortality      Objective        Harvest         

East Panhandle (2002)                600                    120                 80               40                6.7%
North (2014)                                550                     110                10              100             18.2%
Central (2014)                           1300                     260               160             100                7.7%
South (2002)*                              700                     140                 20               80              11.4%

North + Central (2014)               1850                     370               170             200              10.8%

All 4 Huntable BMUs                   3150                     630               270             320              10.2%
________________________________________________________________________________                                       

Information in blue font added by me                

* Figures for the South BMU exclude Big Cypress since it won't be hunted in 2015.


This 3.5%/yr would be the maximum percent of the North+Central BMU population that could be harvested
each year without reducing post-hunt size of the population.  This is like a savings account that earns 3.5%
/yr interest.  If you leave all of the interest in the account, then it keeps compounding year after year: If you
had started off with $1220 at the end 2002, you would have had $1263 by the end of 2003, $1307 by the
end of 2004, … 1844 by the end of 2014, and 1908 by the end of 2015.  If you left the accumulated
interest in the account for another year, you would have $1975 by 2016.  (Table 2)

Table 2.  Potential growth of the North & Central BMU subpopulations [or bank accounts] at various rates:
3.5%/yr which I calculate from FWC figures, and at the 11%/yr which FWC calculates based on an assumed
potential rate of 20%/yr if there were no human-caused mortality.

______________________________
__Annual growth rate___       
3.5%        11%          20%

Year          Estimated Population Size  
2002        1220        1220          1220
2003        1263        1354          1464
2004        1307        1503          1757
2005        1353        1669          2108
2006        1400        1852          2530
2007        1449        2056          3036
2008        1500        2282          3643
2009        1552        2533          4371
2010        1607        2812          5246
2011        1663        3121          6295
2012        1721        3464          7554
2013        1781        3845          9065
2014        1844        4268        10878
2015        1908        4738        13053
2016        1975        5259        15664
______________________________

Now suppose that you give this account to an elderly aunt, telling her that if she takes out $64 (3.5%/yr)
this October and each October from now on, that size of the account will stabilize at $1908 by October of
each year just before withdrawal, and $1844 after withdrawal.  But then some friend of hers convinces her
that she can actually withdraw $200/yr.  If she doesn’t actually pay attention to her bank statements, and
just keeps spending $200/yr, she could get away with that for 6 years, but would go broke in the 7th year.
(Table 3).


Table 3.  Potential decline of a population [or bank account] which can grow at 3.5%/yr, but which is being
harvested at 200 bears/yr [or $200/yr], based on the assumption that it can withstand 11%/yr harvest.

_______________________
Estimated Population Size  
_______
Pre-hunt   Post-hunt
2015        1908        1708
2016        1768        1468
2017        1519        1219
2018        1262          962
2019          995          695
2020          720          420
2021          435          135
2022          139              0
_______________________

That’s equivalent to FWC claiming that it can harvest 200 bears/yr from the North+Central BMUs –
potentially year after year, based on the erroneous belief that the growth rate for these two BMUs is not
3.5%/yr but 11%/yr (Table 3).  

Unlike a bank, Nature doesn’t send you a balance statement at least once each year.  You have to go out
and do a new census to know whether the population has grown or shrunk each year.  FWC has given no
indication that a new census is planned within the foreseeable future.  So over-harvesting a BMU
subpopulation might not be detectable until the population is crashing.  If FWC’s own figures for growth of
these 2 BMUs is valid, then harvesting 200 bears/yr, on average, would tend to halve the North+Central
subpopulation by 2018.

The FWC might, of course, argue that if any subpopulation was shrinking so rapidly, this would be reflected
in a decline in hunter success rate (percent of hunters who kill a bear each year).  However, hunter
success rate can vary greatly due to several factors such as length of the hunt, number of hunters per day,
and weather.  So 3-4 years might pass before FWC could be sure that there was a consistent and severe
decline in hunter success rate – by which time the population could be reduced by half.
Blowing the Whistle About Over-Harvest of The Florida Black Bear Population!
by
Stephen F. Stringham, PhD
Index of  Bear  Webpages
WildWatch
"Making good conservation good business"
wildwatch_consulting@yahoo.com
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39200 Alma Ave.    Soldotna, AK  99669
(c) 2016 S. Stringham