Rogue, also known as noue, langue, rave or just œufs de poisson is the egg-filled ovary extracted from a fish. The rogue de cabillaud is the kind you’ll see the most in France, which is often pan fried or smoked; it’s also used to make the Greek tarama dip.
The ovaries of the red tuna or flathead grey mullet are used to make poutargue.
Image by Maksim on Wikimedia Commons