|The following is based on Fallout 3 cut content and has not been confirmed by canon sources.|
Mirelurk Ecology is a perk cut from the Fallout 3 add-on Point Lookout. It doesn't appear in the game and can only be obtained with console commands.
After hours of study, you have managed to exploit the weaknesses of mirelurk and now have a damage bonus of 5 when you attack one.
The perk was intended to grant a bonus damage of 5 per hit against mirelurks, similar to the intended effect of Ghoul Ecology against ghouls.
Behind the scenes
The Mirelurk Ecology perk was meant to be obtained after reading a book titled Marsh Hunting Tips Vol IV: Mirelurks. How the book was to be obtained is not indicated. The book still exists within the add-on's resources and, if somehow obtained, will grant the perk when used. PC users can obtain the book by using the command player.additem xx00fc2f 1.
A similar book was created (and not used) for the Ghoul Ecology perk, titled "10 Indisputable Rules On Ghouls".
- Due to a misplaced condition, the Mirelurk Ecology perk has no effect. The perk is intended to check whether or not the creature being damaged is a mirelurk, but instead runs that check on the owner of the perk, i.e. the player.