Drama on the loch

I went to check on the swans - still sitting.  Witnessed the hand-over of brooding duty.

While I was there, Mrs Mallard appeared with her 9 ducklings (top image)
Suddenly there was a small disturbance and one duckling disappeared from sight.  Mum gave a squawk, rushed to the spot and stuck her head under water.  She then ushered her brood, now reduced to 8, into shallower water.

At the same time, a triangular fin broke the surface (cue: 'Jaws' music).
Now that fin matches the dorsal fin of a large carp but they don't normally predate small birds.  Pike are also known to inhabit the loch, and they do prey on water birds.  Maybe the carp was in the wrong place at the wrong time and undeservedly gets blamed.
(A pike's dorsal fin is more rounded and situated much further back towards the tail.)