Hi
I think the hand etching says 'B & Toso' (it's not a double 'T' it is '&') then 'Murano' alongside - I have had a look at a few etched Barovier & Toso marks and they can be pretty 'all over the place' - also see Ivo's A-Z.
With pieces I have looked at the Barovier&Toso often melds into a scribble, that uncovers my reservation - your lovely item says B & Toso - all the items I have looked at are fully signed Barovier & Toso. Anyone able to answer this, 'B & Toso' ever used?
As to the object, not knowing the full range of Barovier & Toso designs, I would say your shark/fish is within range.
This is just my opinion.
Any chance of a photo of it standing upright, I mean on it's foot at a short distance?
Adam P