Strategies to reduce over fishing
A quota set to limit the total weight of fish that can be landed. Quotas can be allocated to each boat. Quotas can work well when there are shoals of single species. In mixed shoals many other species can be caught in the net. If a quota for a species caught in the net has been reached, they have to be thrown back.
Minimum catchable size
Catching small fish may produce a smaller total catch so they should be left to grow and be caught later. By increasing the net hole size, smaller fish can escape and go back into the population. Net mesh have a minimum hole size.
Fishing effort limits