I heard a biologist once say that freshwater creeks and lakes were in good shape (ecologically) if they had good snail populations. I’m assuming the same is true of bivalves. The populations of both were drastically reduced when the cormorants had taken over the lake a few years ago. Now they’re gone (thankfully) and the lake’s small critters seem almost back to normal.
So, The D took young B out fishing, with hopes of actually catching something!