CRJ200 Captain describes fatigue inducing six to nine leg duty days with up to six days on duty in a row.

Narrative

This is an incredible amount of flying for one day. We blocked 9 flights with approximately 6 hours 4 minutes of flying in 20-30 minute increments with no breaks. And this was Day 6 on duty for me. Our pilots are flying these schedules day in day out for up to 6 days in a row. After about 6 legs; I could sense my alertness and my reactions to our changing environments was beginning to deteriorate. In addition; I could sense that I my attention to detail was compromised; in other words; sloppiness. It's an alarming feeling as I play 'Monday Morning QB'. My First Officer and I talked about ourselves being tired; but we 'pushed' on through to get the job done.Our schedules are failing to provide the highest standard of safety. Our job demands the highest standard of professionalism; alertness and safety. It's as if our pilots are covering the flying that could easily and safely be assigned to 2 pilots. I suggest that we reduce the maximum number of flights a day to 6. After 6; the 'chain' of events that leads to mistakes; accidents; incidents and oversights tightens and the likelihood for error increases dramatically. A simple snapshot means that our pilots are flying essentially 36-48 flights a week. Six to nine legs a day 6 days in a row. Over a two week period that is approximately 72 flights! Please listen to the pilots.