We see this on the lower Dee all the time at this time of year. There will be nothing happening and you suddenly see the gulls going up to the top of the stream and coming downriver in a feeding frenzy. At that moment Sea Trout kelts also come onto the feed along with the finnock. Sometimes lasts for up to an hour and at other times only a few minutes. There have been some very good hatches in the past 2 weeks Strangely when the hatch is on fish are almost impossible to catch even with an imitation of the fly hatching. As soon as the hatch is over they will take the artificial fly no problem. Strange!!