Gaffer Jack

Source
Gaffer Jacks can be fished in Darkshore along the coastline. They can be fished up with any successful cast, unless the line is inside a Lesser Oily Blackmouth School.

Gaffer Jack as a quest objective
This item is an objective of.

It is worthwhile to pick up the fishing quest from  just south and seaward of the Inn and do them concurrently. Both require random catches from the same water.