Today I learned I should poke the eyes out of dead fish

I encountered the above image on the interestingasfuck subreddit, apparently a sign at a fish-cleaning station at a resort or motel.   I thought it might be a joke, but apparently not.  This was one explanation offered:

"So the eyeballs are buoyant. Might be the eyeballs themselves, but someone said gas builds up behind the eyes in the sockets after the fish dies, but either way, once you take all the filet meat off the fish and toss other scraps, the bony carcass with intact eye balls float. Stabbing the eyeballs makes that carcass sink.

Why do we care about that?

Because floating carcasses tend to decompose on the surface, produce smells, and attract more birds for longer periods of time. This is very unpleasant for anyone living, working, or spending leisure around that dock area. Sinking the carcasses forces the decomposition to happen underwater and feed underwater ecosystems, like other fish, crabs, etc. This is generally good for the water ecosystem and prevenrs smelly carcasses and overzealous gulls and pelicans from swarming the areas, also creating more bird poo, noise, and smells."

All of that makes sense.  When I was a kid and my dad cleaned walleyes at the dock, all of the scraps were just left on the shore for land-based carnivores and eagles and other raptors, or tossed in shallow water by the shore.  Perhaps the need for eye-piercing is more relevant at resorts used by large numbers of fishermen.