It is relatively well known that Captain Sigmund Fairgraves was an explorer and sometimes a pirate.
What's less known is that Fairgraves was a whaler of some significance. This is interesting, of course, because whales make up only one percent of all sea life. When you catch one, however, it pays for all the rest of the fish in your net.
Excellent. You have passed the gear check and appear to have a fishing rod. A rather nice one, too. Now you are ready to catch some of Wraeclast's finest fish.
The next step on your journey to becoming a Master Fisherman worthy of the Winding Pier is to actually catch some fish. Fishing is the simplest thing in the world. With your rod equipped, just approach a pool of water and cast away. It's really intuitive.
Soon, you'll find yourself overburdened with fish of various types. Before you rush off to trade your haul for a better rod though, bring me back a few of the choicest specimens to demonstrate your skill.