My great grandfather was John, his father was David and John married my great grandmother whose surname was Thomas. Their first born bore the Christian names of John David Thomas.
I have three names and sometimes use them all. My middle name is such that it could be a surname and it leads to some people wanting to make me a hyphenated person.
I would take issue with the statement from Guy that some brown trout (salmo trutta) migrate. I say they don't.
Sewin are brown trout (salmo trutta) which, millennia ago, chose to migrate. Others may argue they are a sea dwelling creature which chose to breed in fresh water. I leave that to the scientists.
There are trout which are known a slob trout. These are brown trout (salmo trutta) which live in brackish estuary water but which, I believe, move upstream into fresh water to breed. They will then move back to brackish water. Not really migration, more like moving house than a full blown emigration to a new country.
Within fresh water dwelling brown trout(salmo trutta) some are river dwellers whilst others are lake dwellers.
All in all a very successful species which we must treasure and preserve at all costs.