Thinking that this was a joke or the proverbial fisherman's tale we carried on filming.
Just as we were packing our cameras away to leave, I was amazed to see a young lad rush past carrying a keep net, and inside it was a giant terrapin, some four or five times larger than the domestic animals being sold in local petshops.
The lad, Lee Phelan from Salford, explained that many years ago terrapins were popular household pets, presumably from the Teenage Mutant Ninja Turtles craze from 1980s children's TV.
People apparently got bored with the poor creatures and dumped them in the canal, where they have flourished and bred and over the years, and according to Lee the canal is teeming with them.
He was keen to point out that they can give a nasty bite and should be handled with care, and most importantly, he was returning the reptile to the canal.
If you are interested in catching one, all I would ask is that you throw the terrapin back into the canal - the same as you would with a fish after you have caught it - and let other people marvel at the secrets lurking in the Bridgewater Canal.
This video first appeared on SalfordOnline on the 26th of July 2011, it is reproduced here with the blessings of the Old Age Ginger Turtle (He dyes it we have proof), Mr Tony Flynn.