I am afraid that you can't do much about the subsitance fishermen, sad fact tis that those fish they keep to eat may well be their only way of putting food on the table, then they wont discriminate against type or size of fish taken. I worked in Zim a while back, the local dam in a impoundment of the company was fished by the local subsistance fishermen, and they would even catch and keep two inch kurper.
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