Blast fishing

Blast fishing is fishing with live explosives or something else that causes a shockwave. Throw a bomb into the water, and the dead fish float to the surface. This was called "dynamite fishing" in the late-1940s, when there was a surplus of dynamite available after World War II - nowadays, the explosive is just as likely to be fertilizer-based where the practice still exists.

A related practice is electrical fishing, which kills the fish by using electricity instead of a blast shockwave. The effect is the same.

It's hideously inefficient; The Other Wiki says that for every ten fish killed or stunned, only one or two float to the surface. (And, obviously, none of the shellfish that are killed float to the surface.) The blasts also damage the sea floor or lake bed. It's also dangerous: the fisherman is setting off an explosion or ionizing the water close to the fishing boat... but that just makes this somewhat popular as a comedy trope.

Examples of Blast fishing include:

Anime and Manga

One episode of Rune Soldier Louie shows fishing with high-voltage electricity, over the objections of the person who actually owned property on the shore of the affected lake.

Fan Works

Some Dark Humor in this fan art (image is probably safe, but the site can be NSFW) based on A Certain Scientific Railgun, as the esper who can generate electricity goes for a swim.

Film

Crocodile Dundee does dynamite fishing in the opening of the second film. Then the camera zooms out, and we see he's doing it in New York harbor.

Live-Action TV

Makes an appearance in Wednesday, when Pugsley tries to cheer himself up after his father Gomez is arrested for a thirty-year-old murder. Supplied with what Wednesday notes is his "favorite bait" (for what was apparently supposed to be a father-son fishing trip), Pugsley starts lobbing hand grenades into a pond.

Recorded and Stand Up Comedy

Jerry Clower - "Fishing With the Game Warden" (1978) introduces a (by now old) joke in which a fisherman, Claude, is using dynamite to kill fish. The game warden said, “Boy, that’s against the law, you cain’t do that. Don’t you know you’re breakin’ the law?” Well, Claude done lit another big stick a dynamite, handed it to the game warden... and said, “You gonna set there and argue, or fish!”

Video Games

Borderlands has a "Wanted: Fresh Fish" mission, and Borderlands 2 has a grenade fishing side-challenge.
One of things that the Remote Bombs in The Legend of Zelda: Breath of the Wild can be used for is killing the fish while they're in the water, which makes them easier to collect since they can't vanish when you dive in after them.

Web Comics

THe FReCKLeD FINGeR goes for dark humor, so how about suicide bomber fishing?
Saturday Morning Breakfast Cereal had blast fishing go an unexpected way.

Web Original

"Trout Fishing - Afghan style".

Real Life

Blast fishing is banned in most places for several good reasons — from overkill of everything in the water to handling explosives in the ways prone to having them lost and/or leading to accidents — but it still happens. The Other Wiki has a detailed list on their page on the topic.
- An underwater Catholic shrine was created in the waters off Bohol, Philippines in 2010 in order to discourage "excessive dynamite and cyanide use" in fishing in the area.
Soviet aviation found this "inventive" use for rockets. It's known due to an infamous incident which got Vasiliy Stalin (yes, son of Iosif Stalin) removed from post of a regiment commander: their weapon engineer fiddling with the munition was killed instantly, and others wounded (two of seven "fishermen" were hospitalized per the official report, six out of nine per an unofficial telling of one participant), so this had to be reported.