When do crawfish start becoming active in Idaho?

Hi. I started crawfishing last year. I started around June and I caught over 150. I'm waiting for the temperature to warm up so they become active. I put the traps in about a month ago and caught nothing. Then I tried again on the 21st of April and did catch only one. I tried today and caught nothing. I'm using the same tactics that I was using last year. I have 3 traps that I use. Also, there's a lot of algae on the rocks and I'm not positive if that would affect the crawfish's activity. So to summarize everything, when do crawfish become active? It's in the 70s so I would think they would be active. Thanks.
Crayfish, just like other species of coldwater fish, become more active as water temperatures increase.  As afternoon water temperatures begin to climb into the high 50 degree/low 60's crayfish become more active.  Typically, crayfish activity is high by mid-May.   Just because air temperatures are warm doesn't necessarily mean water temperatures are warm.  This time of the year, many reservoirs are fed by snowmelt yielding water temperatures in the high 40's/low 50's.  River systems like the Boise River, also have bottom releases of water from their dams which tends to promote cooler downstream water conditions which in-turn, slows crayfish activity.  The best places to start looking for crayfish are shallow, early filling reservoirs and then transition to main river reservoirs as we get into June and July.
Answered on: 
Thursday, April 30, 2015 - 10:30 AM MDT