I've been reluctant to try to attribute the whale because the tail doesn't fit the V. Nason or Campanella ones I've seen. It also doesn't look like the Marcolin whales. The tail on this whale looks a lot nicer to me. I think we can say it is most likely not Licio Zanetti because it is not signed.
Does it only have the one dark color shade on back, or are there two layers? Maybe a gray, then a green? It is difficult to tell from the angle of the shot.