Curiosa: Mermaids?

[nebroadwe]

I have a small backlog of curiosa to post, but this one demands to be shared first (at least in part because I have the book in front of me). It comes from the margin of a copy of an English translation of Plutarch's Lives published in 1612 as The Lives of the Noble Grecians and Romaines (that would be the sons of Romulus, not the lettuce, by the way), is scribbled in ink next to the conclusion of "The Comparison of Tiberius and Caius Gracchi with Agis and Cleomenes" in one of the most difficult hands I've ever seen, and reads (more or less) thus:

Mary Mear and yet a mayd
and it [is?] sayd
you may be calld a merrmayd
a merrmayd flesh aboue and fish below
and [soe?]

Beneath which has been added in a different and much neater hand:

and he is a nose that writ this aboue

Mermaids? A nose? Not being an expert in seventeenth-century wit, I'm baffled to explain what's afoot here, though my guess is that it's all insulting. Do the references ring a bell with any of you?