Cladding was a hobby where men would use dogs to catch conger eels buried in the mud. Anglers regularly targeted them now with rod and reel but hunting them with dogs died out long ago.
I've met one guy who had his finger ripped off by one of these things so I'm not surprised they stopped using dogs.
Here's a link to a 4 minute video of cladding.
player.bfi.org.uk/.../watch-gladding-at-watchet-1969-online