Off Nanaimo I generally fish them 270 - 340 ft. Down around Tent Island I've had good luck 225 - 270. Different water I guess. Generally I find leaving the traps over night generates less prawns and less traps. I have tried moving them in shallower at night with no success as it seems they like the deeper water. Hag fish, octupus, star fish and crabs find our little captive morsels an easy meal and if left down too long will find your trap. Currents here are strong, throw in a bit of wind and your traps are gone. Most spots are adjacent to much deeper water and they don't have to move much before they are floating and gone with the current. That's a good point to remember, if the float off, they travel with the tide flow, not the wind. Oh yeah. Don't forget the odd tug pulling a boom. They are trap float magnets and account for quite a few lost traps over a season. Priced at over a $100 per trap, it becomes expensive after a while. Put them down first thing in morning, keep an eye on them and pull them every 3-4 hours and you should do okay. Put some weight in the traps to help keep them anchored but have enough bouy to float them if they do get pushed into deeper water. Make sure your bouys are well marked with your phone number. People are quite good at giving you a call it they see one floating free.
Good luck.
