After the overthrow of Spanish authority on this coast, Messrs. Rundell, Bridge and Rundell, a firm of well-known goldsmiths of London, obtained, in 1823, from the government of Colombia, a ten-year monopoly of the fishery at several places on the coast of the new republic, in consideration of one fifth of the pearls secured.[279] After the independence of Venezuela in 1829, the taxes imposed were so heavy that the industry languished, and about 1833 it was practically abandoned. Owing to the improved physical condition of the reefs, the fishery developed largely in 1845; and for several years an average of 1600 ounces of pearls were secured, an ounce of good quality selling for 150 to 500 bolivars (one bolivar = 19½ cents), and the inferior quality at 80 to 100 bolivars.[280] At that time there was a tax of sixteen bolivars per boat monthly. In 1853 this was increased to forty-eight bolivars per boat, and the use of dredges (_arrastras_) was interdicted, soon reducing the fishery to a very low stage. Subjected to frequent changes in regulations, and burdened by heavy taxes, the industry remained in poor condition until about 1895. Since then the enhanced value of pearls, and the increased industrial activity on the coast, has resulted in a very large development of the fishery. In recent years the government of Venezuela has granted concessions to individuals and to companies for the exploitation of defined areas for a limited period, exacting 10 per cent. royalty on the proceeds of the enterprise. In granting these concessions, the government usually reserves the right to examine the books, and to intervene when necessary in any phase of the enterprise. For protecting its revenue, the government requires that shipments of the pearls must be signed by its agent, and bills of sale must be countersigned by the Venezuelan consul in the place where the sales are consummated.