What are SIC or NAICS codes?
And as far as "Aquaponic" industry, well perhaps part of the reason you haven't found much statistics on it is that there are not that many commercial aquaponic operations that have been in business long enough to really create enough numbers for much in the way of statistics.
What's the best resources for Aquaponics market
What do you mean?
Best resource for connecting with other aquaponics people in the US would be this site we are on right now.
Best resource for learning about aquaponics, especially media based backyard aquaponics would be the BYAP forum.
The Aquaponics Association has just started up this past fall and it will hopefully become a great resource for aquaponics world wide but it is still new and working on getting set up right now.
What kind of resources are you looking for? Education? There are training courses in commercial scale aquaponics in a few places (The University of the Virgin Islands has the longest standing aquaponics training/research program.)
If you want resources for marketing produce then you might look to the extension services and farmers markets and CSA programs for tips instead of trying to specifically look for aquaponics marketing. You might find some info on greenhouse and hydroponic production that might be useful to you though.
If you want resources for marketing fish, you probably want to look up aquaculture resources for tips.
Aquaponics as a commercial venture is so far a very small and not really organized "industry" seeing as the association only just started up this past fall and it isn't like every state even has people doing "backyard" aquaponics let alone anyone trying to make a go of it commercially in every state.