Four large fish lined up across the track.
Who caught these fish?
Who lined them up and left them there?
No-one else was around, it was cold and getting dark and I did I double take then kept going.
edited to add:
Consensus amongst the facebook experts is that the fish are carp. Carp is not a nice fish. They are in the same family as goldfish were introduced from Europe & Asia. By feeding on the bottom of our waterways they destroy the environment and push out the native fish.
It seems that you can eat the fish but they are not popular, except in Asia, and if you catch them you cannot throw them back but should dispose of them humanely.
Not sure if lining them up on the track is humane or a warning to other carp to beware. Some of the jokes about carp-eting the track were well received but I like Marianna's comment about candy the best.