Not surpirsed at all.
We netted a small backwater at Medmenham once with the help of a fisheries man, Martin Moore (he's bloody good, if you want his number Email me).
Just after lunch he came walking along the bank cradling a 6 lb pike and said "Take a look at this."
I thought he was going to show me some horrible sores, which a couple that we had removed had some hideous wounds. Then he turned the pike around.
6lb pike with another pike of at least 4lbs down it's stomach and the tail filled it's mouth.