To me there are two issues at stake: taking their 90% claim at face value that may very well still leave them a very effective charity.

I am more concerned for the fishing stock. Assume 5% chooses to use their nets to fish with - is the this enough to have a material impact on fishing stocks? Will this effect the community to the point that the rest also have to use these nets to catch enough fish? Even if not, what is the effect of the insecticide?

Your articles seem to be really convincing with usages rate, but unfortunately rather handwavingly with the insecticide.