Grinner2,
On Wivenhoe during summer the catfish would hit the lure if you trolled under 3 kph, and the bass would hit the lure anything over 3.5 kph up to 6 kph. So try running the lure quicker maybe?
I'm told Catfish are lazy buggers and won't chase anything going too quick. Give it a try.
Cheers,
Pete