A more thorough explanation:

Definition: Piscary refers to the right to fish in waters on another person's land.

Example: John owns a lake on his property, but he allows his neighbor, Sarah, to fish in the lake. Sarah has the right of piscary on John's land.

This example illustrates the definition of piscary as it shows that Sarah has the legal right to fish in John's lake, even though it is on his property.