1. Bony fish drink a lot of seawater to say hydrated and excrete the concentrated salts through the gills and gut. With cartilaginous fish, they are expected over the gills, within urine, and rectal gland.
2. Cartilaginous fish are slow reproducing, and bony fish are fast reproducers.
3. Some sharks grasp the females pectoral fins, or bite and hold onto the body.