We lived a short walk from the beach. There was a reef about 50 yards out that created a protected lagoon at low tide perfect for swimming. The reef was partially exposed at low tide and was a wonderland for us kids to explore. The reef was full of pockets and little caves and nooks and crannies. It was covered with sea urchins and starfish and growing coral. Tropical fish swam in and out of the nooks and crannies by the zillions. Beautiful little creatures, brightly colored and oddly shaped.
We had a salt water aquarium at home and decided to catch some of those beautiful little fish. Apparently that was a common thing to do, as well as the fish being caught to be eaten by the locals. Every low tide there were dozens of people out on the reef with little fish nets trying to catch those crafty little critters, some were Americans and some were Okinawans. We tried it too, and it was a very low percentage game, being extremely difficult to corral those fish into a net when they had the terrain and their speed to their advantage.
We had been at it a couple of days when our mom showed us how to catch them with a mason jar, a piece of string and a pinch of cornmeal. She tied the string around the top of the jar, filled it with sea water and put a pinch of cornmeal inside. Then carefully lowered the jar down to where the fish would find it. When the fish went into the jar to get a bite of cornmeal she simply raised it up by the string and voila, fish caught. Easy as pie and you could catch dozens an hour. It's how she caught minnows for bait when she was a young girl.
We quickly had enough fish for our aquarium and went home. Next day we came back to swim and there were dozens of people out on the reef as usual - but this time every one of them with a mason jar on a string. Seems we had been observed the day before and the idea caught on fast as lightning.
Never underestimate a Texas woman, no matter what country you happen to be in. Never underestimate how closely other fishermen watch you or how fast they will catch on to your techniques either.