The black bullhead (Ameiurus melas) originally comes from North America. Outside of their natural range they are highly invasive. This small catfish grows to only 20cm, but reaches huge densities, is very tough, tolerant of poor water quality and able to survive temperatures up to 35°C with low oxygen. It has a very broad diet, including our native fish, guards its eggs, has (as our officers discovered to their cost) vicious, sharp spines in its fins and shoals in balls for added protection from native predators as well as carrying novel parasites and disease. The fishery in North London had succumbed to this highly efficient invader, and the local angling club had lost one of their best fisheries. The club contacted the Environment Agency fisheries department and the operation to remove the catfish was planned. The angling club chairman said

“the EA fisheries department has been great to work with. Our fishery had declined to such a poor condition; all due to this menacing non-native catfish. They conducted the operation and dosed the chemical treatment in our lake with military precision. As a club we look forward to restocking with native fish and returning our fishery to greatness again”.