Date of disappearance: Possibly 19th Century
Reason: Pollution, over-fishing, dams and weirs
Special powers: The sturgeon is an extremely ancient fish, that can grow to around 6 metres in length. Before rivers were dammed and wiered, it would migrate deep into the heart of the country to spawn. Those that died at the end of this journey provided a massive supply of nutrients for a wide range of wildlife.
Suitability for reintroduction: This would be one of the most difficult reintroductions of all, requiring both a reduction of fishing pressure at sea and improvements in the flow and water quality of rivers.