The purpose in its most simplest context...

To gain control over natural abundance/God provided food supply... To manufacture scarcity via "management" as to deny food availability so the people cannot feed themselves outside of the system of governance...

The tools used are purposeful over harvest to create scarcity via commercial exploitation under the guise of global demand vs maintaining natural abundance via responsible subsistence harvest models... Responsible subsistence harvest,, without limits,, "only take what you need for food" without regulation would not even impact stock abundance and allow carrying capacity to rebuild to natural levels...