This article mentions nothing about mutant shrimp. Seems like they might have even had a decent shrimping year.
http://www.nola.com/business/index.ssf/2012/01/gulf_shrimp_harvest_numbers_ar.html
My neighbor owns a restaurant in Uptown New Orleans. He gets seafood, including shrimp, from the Gulf. Nothing is wrong with the seafood from the Gulf.
This article is scare-mongering and full of lies.