Do I understand you correctly? The caviar of Dwarf sturgeons is among the best in thew world, and they have a breeding program? Where you referring to dwarf Sturgeons specifically or to a multitude of smaller sturgeons?
Pseudoscaphirhynchus hermanni Is the species I was referring to.
http://www.fishbase.org/summary/8764

They are quite rare due to habitat destruction if I remember correctly. Here is another dwarf stugeon that come in at about 18"
http://www.fishbase.org/summary/4634

One problem: Shovelnose sturgeons are protected species in most states make obtain them legally would be difficult. Another problem is you're claiming a 24" Shovelnose is rare in the wild, you're wrong we captured 50+ ones between 20-28" in a small section of the river in a single day. The Shovelnose might have good caviar, but they're less meaty and much armour than most sturgeons makes them less ideal candidate for aquaculture.
Shovelnose sturgeon are widely bred in captivity for repatriation to it's former haunts. In some state they are still fished for commercially,
http://www.fishbase.se/summary/2596

for some reason a great many are also being shipped to China along with Polydon spathula.
http://www.fishbase.org/summary/174
Captive bred specimens are legal to keep in some states, other will require a permit.