So as many of you may or may not know 3.3 is coming introducing the lich king fight and some other goodies, but, as quoted from the wow forums
Coming in patch 3.3.0, the esteemed tuskarr of the Kalu'ak are proud to introduce to Northrend the Kalu'ak Fishing Derby, a test of fishing skill with a healthy dash of luck! Every Wednesday beginning at 8 PM players can try to catch the elusive Blacktip Shark. Elder Clearwater sits in Dalaran for one hour awaiting the return of the quickest, most experienced fisher to bring him the first catch of the night. This champion fisher will be rewarded in-kind for his or her fishing expertise. Those who aren’t able to return with the first catch will still receive just reward for getting the Blacktip Shark to Elder Clearwater before he takes his leave.
It is said that these sharks’ favorite meal are the bite-sized Pygmy Suckerfish. Perhaps a hook in their waters will do the trick. Because of the increased concentration of fish, you have an increased chance to catch a shark from fishing pools. Don't forget, in patch 3.3.0 you never catch trash from fishing pools, regardless of skill.
The derby winner will receive a substantial chunk of experience (or money at maximum level) and gain 5000 reputation with the Kalu'ak. In addition, the champion will be given a choice between two unique rewards:
Dread Pirate Ring
Binds on Account
Unique-Equipped
Finger
+34 Stamina
Requires level 1 to 80 (80)
Equip: Improves critical strike rating by 53.
Equip: Improves hit rating by 29.
Equip: Experience gained from killing monsters and completing quests increased by 5%.
Boots of the Bay
Binds When Picked Up
Feet
Requires Fishing (200)
Equip: Increased Fishing +15.
Use: Whisks you away to the finest drinking establishment in Booty Bay. (1 Day Cooldown)
To keep it interesting, the Achievement "Master Angler of Stranglethorn" has been changed to "Master Angler of Azeroth." This can be earned by winning either the Kalu'ak Fishing Derby or the Stranglethorn Fishing Extravaganza.
There is the details on the tournament
Now; How to win it.
Actually winning seems a little rng dependent but there are some ways to get an advantage
Step 1: Fly around before the tournament looking for pygmy suckerfish pools, if you can find a couple near each other more power to ya.
Step 2: Have an epic flyer, this is imperitive to succeeding at the tournament, if you can outfly everyone this is a benefit to you
Step 3: Set your hearth to the town where the elder is going to be, this is imperitive to success
If you follow these three steps there is no reason why you should not win the tournament