Wiki - Whale Fishing
For those who enjoy the path of the fisherman but feels they've accomplished all there is to do with it, Legends of Sosaria introduces Whale Fishing!
To fish whales players will need to acquire Legendary Fishing Nets from Ancient SOS chests. The nets require 130 Fishing Skill to use, which can be gained naturally after the purchase of a 130 Power Scroll from our store; or by wearing Bonus Fishing Gear attainable from completing Fishing Bulk Order Deeds.
Legendary Fishing Nets work exactly like other fishing nets. Double-click them and then target the water outside your boat. Most times the net will stir up some denizens of the deep that will attempt to purge their space of the players presence. Among these creatures are Sharks, Scylla, and Water Tentacles. Sometimes, however, the net will drag a Whale to the surface.
Whales, as might be expected, are tough and will take some time to kill. They are also capable of damaging ships, which makes them particularly dangerous. To add to all that, fighting one may also attract the odd shark. The rewards for defeating a whale, aside from a large amount of food, is the remarkable amount of treasure they've swallowed. Among the potential treasure are several new Lost Sea Artifacts. These can be seen in the Display Gates area under Custom on the World-Omniporter. Look for a gate marked Custom Artifacts.
It is also wise to carve the corpses of whales. Doing so will reveal a second treasure of an SOS chest buried within it's belly. The chest will be deposited on the deck of your ship.