Many types of marine life can live in the Black Sea. Fish such as anchovies, sardines, mackerel, and sturgeons are commonly found in the Black Sea. Additionally, the Black Sea is home to many species of crustaceans, such as shrimp and crabs, as well as mollusks like mussels and oysters. Marine mammals such as the bottlenose dolphin and the common dolphin can also be found in the Black Sea. However, the Black Sea's unique hydrographic conditions, such as high salinity, lack of oxygen in deep waters, and high levels of dissolved hydrogen sulfide in the deep waters, restrict the types of marine life that can survive in the deep waters of the Black Sea.