What is the males shark called?

Male sharks are simply called male sharks. There isn't a specific name like "buck" or "bull" for a male shark.

However, some species have specific terms used to describe their reproductive behavior or physical characteristics. For example, in some species, a male shark that is ready to mate might be called a "mature male".

It's important to remember that the terms used to describe male sharks can vary depending on the species and the context.