Now I know Wikipedia isn't the fount of all human knowledge but Wikipedia, sea snakes would suggest that some species can be found in depths of upto 90M. However it also indicates that most species of sea snake are docial.
Docile, docile...come on your ruining my whole movie plot here. KILLER SNAKES can not be docile...
Seems awfully large (6 metres), isn't that like around an 18 footer. Must be a relative of the Loch Ness Monster. If it is an eel, do they get that large, were talking Anaconda size here...

Seems from the story that they have been working the site for a very long time (years), would seem that they would have been able to at least verify who the damn plane belonged to by now. My conspiracy theory mode is telling me that they want everyone to believe that it is AE's plane so no one is gonna pop-up and try to put a claim against their "found" lode of gold.
LTM,
Don