What function does the fatty liver in sharks serve?

The fatty liver in sharks primarily serves the function of buoyancy adjustment. Sharks do not have a swim bladder like many bony fish; instead, they rely on the liver, which is rich in lipids, to help maintain buoyancy in the water. The fat within the liver is less dense than water, allowing sharks to achieve neutral buoyancy at various depths without expending energy on swimming. This adaptation is crucial for their lifestyle as predators, enabling them to conserve energy while gliding through the water column.

While energy storage is indeed a function of the liver, the specific role of the fatty liver in sharks is more significant in buoyancy regulation than simply as an energy reservoir. It is also important to note that the unique anatomy of sharks means that respiration occurs through their gill structures, not through the liver, and digestive processes are facilitated by other organs rather than being improved directly by the liver's lipid content. Thus, buoyancy adjustment is the most accurate representation of the function served by the fatty liver in sharks.