Mr. Jifa is obviously very inventive and resourceful, but dynamite fishing is actually quite detrimental to underwater ecosystems, kills more fish than are harvested, and because of this, is illegal in most of the developed world.
"Underwater shock waves produced by the explosion stun the fish and cause their swim bladders to rupture. This rupturing causes an abrupt loss of buoyancy; a small number of fish float to the surface, but most sink to the sea floor. The explosions indiscriminately kill large numbers of fish and other marine organisms in the vicinity and can damage or destroy the physical environment, including extensive damage to coral reefs" [1]
I'll tell you what a lame-ass thing to do is: Criticizing the ostensible environmental insensitivity of a guy who, amidst grinding poverty the likes of which you and I cannot properly imagine, lost his arms trying to feed himself and his dependents.
Things are tough all over. Now that I apparently have your permission, maybe I'll go camp out in Bill Gates's back yard tonight and spotlight some deer.
Yeah, freakin' poor people. If they were decent human beings they'd be living green, sustainable, carbon-neutral lives respectful of Mother Gaia. It'd be nice if they weren't poor, but since they're such greedy anti-environmental jerks, they probably deserve it.
If the fish aren't biting and your children are starving, you're going to do what you have to do.
Though blast fishing is inconsiderate to the fish, I'm not sure that I would personally justify a man losing his arms because he was acting in a detrimental way to the local wildlife.
Karma is mostly understood to mean "cause and effect". Not "do bad things and you will be punished by the universe". A famous buddhist teacher once was asked why a man had been hit by a car. He answered "He wasn't looking where he was going".
I would say that being able to be concerned about the (very real) negative side of dynamite fishing is something of a luxury. I can't say if he could afford that luxury or not, but if he had to build his own prosthetic limbs then I am inclined to think that he could not.
"Underwater shock waves produced by the explosion stun the fish and cause their swim bladders to rupture. This rupturing causes an abrupt loss of buoyancy; a small number of fish float to the surface, but most sink to the sea floor. The explosions indiscriminately kill large numbers of fish and other marine organisms in the vicinity and can damage or destroy the physical environment, including extensive damage to coral reefs" [1]
1. https://en.wikipedia.org/wiki/Blast_fishing