Mr. Whiskers is correct... they are filter feeders, just like whales. They cruise through the water with that big mouth wide open just like a vacuum cleaner. Use gill rakers to filter plankton out of the water. When one is caught, it is simply because it happen to swim into your hook with it's mouth wide open. And yes, since international law has curtailed them importation of sturgeon roe (the highest quality cavier), spoonbill eggs have become a popular substitute. Always used, but has become much more valuable. The last I heard spoonbill roe I think was selling for around $40 per pound. A large female can have 5-10 pounds of roe. Commercial fishermen have been lobbying TWRA hard, ask them to re-open commercial (net) fishing on Watts Bar specifically because of spoonbill. The lake has been closed to nets for 20-plus years after rockfish were stocked. The spoonbill population has done well, and several commercial fishermen desperately want to partake. There a lot of research going on across the country studying the status and future prospects for spoonbill. They really are sort of a "mystery fish." As a game warden I spent a lot of nights hiding in the riprap below Nickajack waiting on folks to show up to try and snag spoonbill below the dam (illegal within 1,000 yards of a dam). It was great fun! There were actually several commercial fishermen based in Marion County who much of their annual salary just during the spoonbill run.