The decline can be very rapid and dramatic, fishermen have to work harder and harder to maintain their catch levels (my hometown was one of the ones that suffer

The decline can be very rapid and dramatic, fishermen have to work harder and harder to maintain their catch levels (my hometown was one of the ones that suffered with the collapse of the northern cod fishery): https://en.wikipedia.org/wiki/Collapse_of_the_Atlantic_northwest_cod_fishery https://en.wikipedia.org/wiki/Collapse_of_the_Atlantic_north... In the 1990s the Northern Cod populations collapsed to less than 1% and after a 20+ year moratorium on fishing has only increased to 10% of its historical stock.