Shark pools are a type of aquarium that is designed to replicate the natural habitat of sharks. They are typically large, deep tanks filled with saltwater and equipped with filtration systems to keep the water clean. The term 'shark pools' comes from the fact that these tanks often contain multiple species of sharks, allowing visitors to observe them in their natural environment. The answer to the crossword puzzle is SEAS, which stands for 'Saltwater Exhibits and Aquariums Society'.