I have copied a link to Gwent Angling Society web page on the life of Dr. Wade a man who never fished until after his marriage, who then decided if you want to catch the fish find out what they eat, this is a brief introduction into his life on the River Usk.
http://www.gwentanglingsociety.co.uk/articles/entomology/dr-michael-wade-a-man-of-the-river