As for the people who go fishing in rivers, you rarely hear anything sad happened to them in the cost of fishing because they have a prerequisite that they take into account before going for fishing, I'm not from the riverine areas but I know this because Africans a more smart than you can imagine. I believe before a kid can be taking along side for fishing the kid must have passed through a series of exercises and tests to know if he or she can cope with the rules for fishing, this rules can be that the kid must be able to swim across the river at every instance etc. the prerequisites has been what has guided Africa for millions of years.