Normally fish regulate their buoyancy by using an air filled sac located near their stomachs called a swim bladder. A fish can decrease air to sink or add more air to float. However, with deep water fish, a swim bladder is not necessary. Sablefish are a great example of a deep water fish that does not have a swim bladder; instead they use oils in their flesh to regulate buoyancy. Due to this interesting life strategy, Sablefish meat is very rich in oils including the healthy Omega-3. Having such high amounts of oils creates the delicate and buttery flavor found in all Perciformes Sablefish!