I did not know they farmed them there. AFAIK, there are no feral populations of iguanas. We do have a lot of goannas, though, many species from 20 cm to 2 m in length.
I met a full sized goanna when I was trekking in the Blues once. Walked right up to me as I was filming and backing up as fast as I could. Heart was beating like a low-down guitar.
They farm alligators and iguanas, remember the guy that protested by dumping one by the Executive Yuan?
The problem is that, as with the ibis, many iguanas escaped. Unfortunately, we cannot make them soup -actually, in the old country we make them stir fried.- as wild ones are full of parasites, yucky.