Why Royal Navy clergy were called the Bish

Why did the Royal Navy call its resident member of the clergy the Bish?

With no bishop at sea, the ship's cleric stood as the local religious hierarchy and acquired the nickname Bish.

The nickname plays on naval command and church hierarchy. At sea, the captain was master under God, while the resident member of the clergy provided the direct religious authority aboard. With no bishop at sea, that cleric functioned as a local ecclesiastical superior. The colloquial name Bish condensed that status into long-standing Royal Navy slang.