But as you say, even at that rate, with their abundance and world wide availability they would quickly become a very popular target. 

The UK and european mullet fishing info is very interesting. There is absolutely screeds of it on the internet. Some massive mullet too. 

Unfortunately, all of the UK stuff relates to two mullet species that are completely unrelated to our grey mullet (Mugil cephalus). I have read much of the info in the hope of gaining insights into a possibly successful strategy, but at the end of the day this could all be red herring info that is leading me down the wrong path.

The big difference you will see with the UK mullet and with those species that are caught regularly on fly in other parts of the world is that these species are also caught fairly regularly on baited hooks. Our Mugil cephalus is caught on baited hook only rarely, wherever it occurs in the world and there has been some very limited success with flies, sometimes in association with various forms of berley ( shouldn't even mention that word ). Indeed - it is the Mugil cephalus fly fishing mystery that is waiting to be cracked.

The fact that these fish are happiest eating detritus, algae and plankton suggests that fly fishing will ultimately deliver the best method for catching them on a regular basis. 

My system is to take some of those methods for UK thick lipped mullet and tweak them until they work on Mugil cephalus. I personally think this will involve quite a different type of fly and fly presentation. What this ultimately will be I can not say. But I have got a few small clues.

Anyway, it's a fascinating way of getting in lots of casting practice! 

As you say - I'm not too sure whether it correlates to what mullet do on the shallow flats or whether it will work on them in a shallow harbour feeding situation, but all info and success on mullet is worth examining and adding to the puzzle.

I have seen those small groups of spawning mullet at the mouth of the Manukau many years ago. What is interesting is that when the mullet spawn here they are in much bigger schools and they go right out past the islands. They can be seen slurping something off the surface when they're like this. Possibly they switch on to more of a plankton diet at this time? It is similar to the mullet schooling in winter that Justin Duggan describes happening in Sydney. They do catch them on small surface flies at this time.