You are not permitted to download, save or email this image. Visit image gallery to purchase the image.
And about 100 people were found fishing in the Ohau C canal system near Twizel yesterday, many of them breaching regulations.
Fish & Game officer Hamish Stevens said people were not allowed take more than two salmon each day, over 500 millimetres in length.
"We just ask that the anglers make sure they know the rules and stick to the rules.
"It makes our job a lot easier and means they don't have to keep looking over their shoulder and wonder when the next ranger is going to tap them on the shoulder."
Mr Stevens said the escaped fish were due for harvest later this year so were about three kilograms.
While it encouraged people to try their luck catching one of salmon, it warned people who took more than their share could face criminal charges.