One of the most obvious yet least talked about ways to marine creatures including the fish we want to catch is to protect the place they live in. Protect the habitat and you protect the future of the fishery.
Scouring the bottom of rivers and lakes with nets ripping out the seagrasses takes away an important food source therefore the fish have to move on or starve. Ripping out mangroves and coastal wetlands for the sake of development destroys the nursery and restricts the population growth of future generations.
None of these scenarios occur during the normal course of recreational angling so there can be no argument to show rec fishers should be locked out of any areas in the name of habitat protection.