Good to hear the capture rate is decreasing. Don't be too quick to pull the trigger on store bought fish though. I would suggest that you have a least 4, preferably 6-8, trapping sessions over a period of 60-90 days with no captures before fish are added.
This gives time for any Cirolanids that are pregnant or full to get hungry and be attracted to the trap.
Definitely a good report though, thanks for continuing to share with us
Brian