I guess you can state that Bitcoin is the main cause of all these markets are fluctuating. The reason that Gulden lags in this correction is the relative large fiat pairing (BTC price remains fairly stable). It's time that the fiat exchanges start pulling this, instead of BTC. Than we could see fireworks, but for now these exchanges follow the BTC price converted to euro (the CMC 1y chart shows this nicely).
Nocks has 61% of the overall volume, when they add USD and GBP pairings they will get 80% of the volume and the rest the exchange prices won't be a concern. It would be good to have Guldentrader doing similar volumes to Nocks when they add their exchange.