Bulgarian scientists are investigating possibilities for extracting sturgeon roe without killing the fish, in order to save the shrinking worldwide sturgeon population. The Bulgarian fish research institute in Bolyartsi, Plovdiv region, has a sturgeon-breeding facility that plants young sturgeon in the Danube river. Bulgaria's Agriculture Ministry has proposed a new rule for financing the planting operations, under which the fishermen, who have received a licence for catching and exporting sturgeon and sturgeon caviar, will pay a fee for the fish planting, reported the Bulgarian News Digest.