No, this is a local croc and accordingly you are not allowed to own one whatsoever. You will also get jail time if caught selling one.
I suspect someone caught him when he was quite a bit smaller. The locals there reckon he has been there for 8 months, I only saw him for the first time about 4 weeks ago, when he grabbed my crazy crawler, Since then i found his lair and see him quite frequently.
matched his patterns on the web and he is a nile croc - one of the potentially biggest species of crocs you get and what is worse, they will grow like crazy. I can only imagine what damage he would do to spawning fish is such a small area.