Quote taken from "flytyer.co.uk" web site.

"There is a commonly held belief abroad that shrimp flies only work in Ireland and that they are at their best for late summer and back-end fishing. This is not so. Shrimp flies from Ireland have been used with outstanding success in Scotland and the north of England rivers. As regards the time of year, salmon in a river will take a shrimp fly as freely as any other pattern, when the water is right, from the very start of the season."