One possible factor (limited to those waters that attach to the ocean via rives and streams or those that once were but are now landlocked)is the presence of alewife ( a herring/shad like fish). It is very high in food/nutrient quality for LMB. I would think that the difference has to be food or genetics based and not location/climate.

http://www.web1.cnre.vt.edu/efish/families/alewife.html

Last edited by ewest; 04/20/16 03:35 PM.