This sequence is so short it would be a crime not to comment on it immediately. What we learn here, after knowing that Geppetto and company are close to starvation, is that Monstro is waking up and hungry.
Woolie Reitherman handles Monstro in shot 2 and I'm guessing that John McManus animates Monstro in shot 5. I find the contrast between the handling of Monstro's eye on these shots very interesting. Reitherman has drawn Monstro's eye in a much more cartoony fashion than McManus. Furthermore, Monstro's timing is rather fast in Reitherman's hands. I think that it works against conveying Monstro's bulk. Reitherman doesn't just move the eye, he moves the whole whale in order to register Monstro's reaction to seeing the tuna. McManus's rendition, besides being drawn more realistically, emphasizes only the movement of the eye; he doesn't move the body. Reitherman takes over Monstro for shot 6 and times his movement appropriately for his bulk.
Personally, I think that the sequence would play better without shot 2. The shock of that eye opening in shot 5 is very powerful as is Monstro leaving the ocean floor. Shot 2 is timed too much like a typical cartoon take, ignoring Monstro's bulk and reducing him from a force of nature to a scheming cartoon character.