Funny you should mention seals, I just saw one on dusk this evening... 47km inland!
I recall duck shooting at this very same spot south of Paeroa at the start of the season, and recall seeing something I dismissed as a giant eel. I told my wife when I got home I had seen the biggest eel I had ever seen in my life just before dusk. I swear it had the head the size of a dog, it even had a muzzle like a seal. Now I know I wasn't losing it :D