Question about the song "Wet Dream" by Kip Addotta

Ok, so the whole song is full of underwater puns and replacing some words with names of fish, and so on. But the very first line
"It was April the 41st, being a quadruple leap year "
I don’t get. How does that relate to being under water or living in the ocean?
Lyrics

I don’t believe it is meant to relate to water, at all. It’s just the first of the series of absurdities that is the song.

Yeah, I talked to my wife about it, and that’s pretty much her opinion too. I guess that sounds right, but I just thought that since every other joke was an ocean/fish pun or joke, that that one would be too, but I guess it’s not.

Yeah, that’s what I get out it, too. It’s just a quick set up for the sillyness to follow. Classic Dr Demento humor. I have it on a DrD collection CD.

They’re coming to take me away, ha ha