Hi Freeroll,

You can find information on http://cryptofresh.com/assets and also CoinMarketCap displays some of the exchanges (Bitshares Asset Exchange, RuDex, Openledger and CryptoBridge - all are listed separately but realistically Bitshares total trade volume combines all these entities) on the Exchange Volume tab (Bitshares Asset Exchange is ranked 51st by 24 hour exchange volume today).

Alternatively you could also look at the Bitshares markets tab and click on the exchange you want.. for example HERE is the Bitshares Asset Exchange which CMC reports as trading 23 Million USD today