Answer: Killer whales, krill, penguins, species of bird,fish seals and cephalopods will be in danger...
Explanation: A Leopard Seals prey consist of krill, penguins, birds, penguins, fish, and seals; so if you took the Leopard seal out of its habitat, or "eliminated" it, the food chain will start to fall. The preys numbers of this creature will start to increase, sure, other things eat the Leopard Seals prey, but that doesn't mean prey will be stable. The Leopard Seals predators will start to decrease, due to the 'elimination" of the Leopard seals.
sorry for the looooong Explanation :D
