as paul stated-ur dealing with a smart beaver now. try makeing a blind set - such as a crawl out-useing a peeled stick or 2 WITHOUT lure. use a *bright* wood,such as maple if possible,(its color is really visible for a few days and doesnt fade out quickly). if no response after a couple days THEN try a food lure with new sticks(simply to freshen color).perhaps try a different food lure. dobbins lures are top notch but even beaver shy away from a high quality lure such as Backbreaker
IF theyve had bad experiences associated to the lure (such as seeing their own floating dead in a trap or haveing a trap snapped on themselves). with the amount of beaver youve caught,im sure this has happened. this is how we get *trapshy* beaver.im surprised u cant catch the beaver in a crossover set on the bottom side of dam leading downstream(since you are limited to conibears i mean). perhaps try a castor mound with a different castor lure.as a last resort go to the house and get it over with. it really sucks youre limited to conibears. you may want to beg the landowner to let u use other traps or snares.explain to them that u may not be able to finish the job because u are so limited to your options.what ever u decide to do,if u catch (or shoot)another beaver, make sure u rip out a hole in the dam to make sure u have got all beaver.