They were fishing with dynamite and cyaniding tropicals in the Phillipines when I was there in the '80's. There was all sorts of protest about this, but it continued under Marcos, then Aquino, and so on right into today. Same story, different day.
In the '70's, the reefs in Cozumel were on the brink of destruciton from fishery abuse, and the local government things around until the Yucatan area of Mexico is a supremely popular tourist destination pouring in many multiples more of revenue than subsistence fishing did.
The fishermen will realize that it is in their interest not to continue this about the time a patrol gunboat fires the first salvos across the bows. After a few times, even the densest fishermen realize that it's maybe time to hang up the dynamite and delete cyanide from the weekly shopping list.
Common sense, indignation, and international outrage does not prevail here.