What year did reporting of the catch become mandatory? Was it the same time that QMS was introduced, 1986?
Was accurate reporting a big issue prior to that time? Did anyone in the various governments prior to the 80's really care how may fish were caught, or wasted?
Apart from trying to avoid income tax why would you fake your catch numbers?
I'm guessing it wasn't out of any concern for the state of the fishery, in those days the concept that you could actually damage a fishery was probably unheard of.
Both Comms and Rec were unconcerned with wastage in the 50s through to the 70s.