I haven't looked through the previously-mentioned thread, so these might have been listed in it, but -

There's an old blues song that I've heard lots of people do - don't know if it's composed or trad, but partial lyrics are:

You say you're goin' fishin'
You're always goin' fishin'
I'm a-goin' fishin' too

You always say you're fishin'
When you're out late
Well, here is somethin'
I'm a-gonna state:
Any fish'll bite if you use the right bait
I'm a-goin' fishin' too


Then there's the kids' song, Dance to Your Daddy, which I *think* is in the DT. ("Ye shall get a fishy/in a little dishy/Ye shall get a fishy/when the boat comes in")

And, of course, all the old whaling songs (yeah, all you anal types, I know a whale is not, technically, a fish).