What Divers Should Know About Shark

Apex predators in many marine ecosystems, sharks exhibit a remarkable range of behaviors far beyond the classic solitary hunter image. While some species fit this description, most lead more social, even sedentary, benthic lives, suggesting distinct personalities among them. Highly social species like scalloped hammerheads frequently congregate in large schools, sometimes over 100 individuals around seamounts and islands, such as in the Gulf of California. Even solitary sharks will gather for breeding or at rich hunting grounds. Divers should also be aware that when approached too closely, some sharks may perform a threat display, often characterized by exaggerated swimming movements.

These fascinating cartilaginous fishes are found in all seas, ranging from the small dwarf lanternshark, a deep-sea species just 17 centimetres long, to the magnificent whale shark, the largest fish in the world, which reaches up to 18.8 metres. Most species inhabit depths up to 2,000 metres. Sharks possess a protective covering of placoid scales, or denticles, which also improve their fluid dynamics, along with numerous sets of replaceable teeth. Their diverse feeding strategies include filter-feeding planktivores, such as the whale shark and basking shark, alongside powerful apex predators like bull sharks and great whites.