You guys should get PB mag if you don't. Here is a part from a prior Cutting Edge article on BG adaptation. Never underestimate the effect of local adaptation on a population.

In the Shoup et al study eight experimental 0.4-ha ponds (one acre with a mean depth of 1m) were used to evaluate the effects of habitat complexity on growth of small bluegill. Each pond was stocked with 15 kg of young-of-year bluegills (30–50 mm total length, approximately 20,000 fish per pond) to produce a realistic density for small ponds. The ponds contained varying amounts of vegetation (plants) and no predators.


The result was - by the end of the experiment, bluegill from the low vegetation treatment ponds were significantly longer – twenty (20%) percent than bluegill from the high vegetation treatment ponds.


..... addressed in more detail is phenotypic plasticity. That is the ability of an individual or population to change due to environmental influences. Can environmental conditions during early development shape individuals’ phenotypes so they become more adaptive to the conditions they encounter? Were the long bluegill that fed in open water that way because longer fish can swim better in open water and were the shorter bluegill that way because being short allows them to maneuver around the weeds better? Plasticity has been shown to effect sunfish (Lepomis) shape, feeding and behavior in some cases.

Last edited by ewest; 01/31/13 09:28 PM.