I don't fish but sometimes took the kids out to the Texas City dike to let them catch a few blue crabs. They would get excited about catching something and then be less enthusiastic about picking the crab meat, so it was not something we did more than a few times over the years, but I'm sure they remember it as a good time. I do.
For those who have never tried it, you tie a piece of raw chicken to a string and drop it in the water. If there are any crabs around they grab the chicken and hang on while you pull them up. They want that chicken more than they care about staying under water.