ANNOUNCE Messy fishery dynamics explained (SD7059)

[SDMAIL Richard.Dudley]

Posted by  <Richard.Dudley at attglobal.net>

Some of you may be interested in a recent paper in Nature which explains 
why fishing can cause even more disruption of fish populations than 
previously thought by creating instability in population dynamics .... 
causing boom and busts in a fished population independent of variations 
in the amount of fishing.  

 From the abstract: "....increased temporal variability in the 
population does not arise from variable exploitation, nor does it 
reflect direct environmental tracking. .......it arises from increased 
instability in dynamics.   This finding has implications for resource 
management as an empirical example of how selective harvesting can alter 
the basic dynamics of exploited populations, and lead to unstable booms 
and busts that can precede systematic declines in stock levels."

 From conclusions: "In summary, fishing for big individuals without 
consideration of the impact on the age distribution can lead to unstable 
nonlinear population dynamics, and this enhanced nonlinearity helps to 
explain much of the volatility seen in fish stocks today."

Source:

Anderson, C.N.K., Hsieh, C.-h., Sandin, S.A., Hewitt, R., Hollowed, A., 
Beddington, J., May, R.M., Sugihara, G., 2008. Why fishing magnifies 
fluctuations in fish abundance. Nature 452, 835-839.
 
Posted by  <Richard.Dudley at attglobal.net>
posting date  Thu, 29 May 2008 09:28:44 +0700