You seem to be getting the numbers but it would seem a lot are shy and don't post, if you could somehow persuade the users you have to post more, then this would be an extremly busy site indeed.
As a relatively new guy here, I would like to see a few more articles on fishing in general, articles on rigs baits there uses etc. people preferences on floats rigs etc
You could also try a banner swap out, with tackle shops a banner for the tackle shop placed on here = a banner for TA on the tackle shop site or even a sticker or two in the shop.
It really depends if you want the forum / site to adopt a commercial approach or keep the freindly family atmosphere.
The user base is very good you got to get them posting