Why do you say that? Did i claim that all humans are fishermen? No orcas do anything else their entire lives, but less than 1% of humans are fishermen (and still negligible even if you include all ranching and agriculture in modern countries!)

And no, fisherman is not a "species" or a pre-defined destiny. Hemingway was a fisherman and a writer. Humans have the ability to do other things, even in the same lifespan. Sounds like arguing for 2+2=4.