Background: I am a correspondent for National Geographic Magazine.  We are working on a series considering the geography of food, and for that I am presently writing about the production of caviar from the Caspian Sea.
Request: I need a report on the extent of and reasons for the decline in caviar production from the Caspian Sea.  I want to be broad in my coverage here, so I am not just looking for verified reports from authoritative sources, but also for speculation and claims by parties that may have their own agendas for making such claims.