I would wonder this also, not that they aren't wild collected. It just seems odd that you can get WC silvers at this time of the year, yet Black aros are not available until the winter months of the Northern hemisphere. To my knowledge all black aros are WC.
Buying wild caught silvers will have nothing to do with the silver getting DE. Take a look through the web 99% of all silver aros (larger then 18")posted have DE.