well first, there might be accidents, for example a fish could get hurt and cant swim properly. if a fish get washed up on a shore of course cant get back by itself. there might be fish on the shore right now trying to get back to the sea while the sun could be hot to them
First, there might be some accidents ,for example a fish could get hurt and can’t swim properly .If a fish gets beached it can’t get back.There could be schools of fish that could’ve been beached right now.
hand a rock to another person and do that in a line what makes it effecent is the fact that one person doesn't have to bring the rocks back and forth on there own