A short (15 minute) video on YouTube details caviar in general, then focuses on the caviar black market in Kazakhstan. The video even shows the narrator going into a local market where hidden cameras show a kilogram of caviar being offered without any CITES or government approval.
Although I have never been to Kazakhstan, a recent trip to Russia rendered similar results for myself. I was stunned to see how easy it was to attain caviar from the local "markets" for ridiculously low prices. Don't be fooled however, as there is no way of assessing the quality of the caviar including its true origins. Sellers at markets are notorious for selling you Beluga caviar, when in reality it is Sevruga or even farmed caviar. Good luck finding them to try to get your money back.
Even though regulations imposed by U.S. Fish and Wildlife services + CITES have driven prices up exponentially, the quality of caviar has also increased with regulation. This is great for caviar purveyors and consumers as any notable caviar company in the United States today is guaranteed to be obtaining their selection of caviar from legitimate regulated sources.