You may have completed the quest prior to this post. Regardless, I will attempt to create a -just in case- post to assist in future endeavors by other players including yourself.
My sincere personal contemplation of the situation at hand influences me to have confidence in the fact that the highest quality scorpion hunting locations for lower and medium levels are as follows:
1. Tortuga, locate the giant scorpion nest in Tortuga. (Stand in front of the Faithful Bride and glance to the right. You'll view a archway. Proceed beneath the archway and continue advancing through the dirt path up to the time you arrive at a cave, [which will be located to the left of the pathway]. Carry on through the cave entrance. Advance down the pathway in the jungle area up to the point you find yourself gazing upon 5 - 7 scorpions bustling about. This is a spot-on area. If you are low level take a friend, providing you have an active one nearby.
2. Devil's Anvil, Launch any ship you prefer. The enemy vessels patrolling Devil's Anvil do not pose a threat to any friendly craft in the area on their way to "Dev's Anv". Not even a crew is a requirement for this short journey. When you arrive, patrol closely to the edge of the towering land mass to discover a hefty supply of scorpions, conveniently positioned next to the beach for your convenience.
Best of luck to you, and future players of this quest.
-Leon Sharkshot-