This is just a thought and may be wrong. But I was thinking that at times of the year some fish hug the thermocline level.
Could it be that by not disturbing the thermocline, keeping the lower water cooler for the trout, they could hug the thermocline and dip in and out of the cooler but low DO water and into the warmer but higher DO water? Don't know, just asking. The thermocline is generally a vary narrow band where the change takes place. Maybe they would hang out in the transition area.
