Teggie - A Giant Fish, or an Explosive Seal?

Nick Redfern has a new post on Mysterious Universe about a Lake Monster most people probably haven't heard of, at least I hadn't. The post is about Teggie, the monster seen in Lake Bala, in North Wales. Teggie is apparently supposed to be a violent lake monster.

Theories of what Teggie is range from  an ancient creature that has survived to today, giant fish(that has something to do with a known fish in the lake, the Gwyniad), or even explosive seals. Yes, I said explosive seals.
A Gwyniad

Is Teggie a seal?

You can read Nick's whole article on Teggie here.