"He's certainly a long way away from home. It's not very deep in that channel. It's part of the flood system that was built to take the excess water off the Maungatuas. It's only half a foot wide in places and only a few centimetres deep. In other places it's just mud."
Mr Kerr's father Alistair, who has owned the Maungatua Rd farm for 25 years, said he had never seen anything like it.
"It looks like he's swum up the Taieri River into Waihola and Waipori and then up the contour channel.
"I suppose he's already eaten all the fish in there. I'm a diver, so I'm not really a big fan of seals."
Department of Conservation coastal ranger Jim Fyfe said the seal looked "happy and healthy" and was probably aged about 3 or 4.
"We've had a couple of calls about it and we've been monitoring it for the last few days. It looks like he's followed the river up and, hopefully, he'll be able to follow it back down again," he said last night.
"It's not uncommon to to get seal sightings in the Waipori or Lake Waihola every few years. There's a tidal influence and seals and sealions were designed to explore waterways."