Surprise sardines

I went for my 3 mile Tuesday lunchtime run yesterday, and halfway round I came across a large pile of sardines. I wasn't hallucinating or sleep-running. The pile was surprisingly big - two or three metres in diameter. All the fish were dead, and some were half eaten with their guts spilling onto the pavement. They didn't smell unpleasant or fishy. The intact ones looked quite pretty, as oily fishes can - silvery and shiny. My route isn't next to the sea, it's on city roads which typically contain cars and bicycles rather than barbecue fodder. I was trying to run fast on tired legs so the fact that I'd just discovered something completely inexplicable didn't fully register with me until a few paces later.

I don't understand, and I probably never will. Maybe they fell out of the sky like these ones in Australia. Fishy.