(Reuters) - African coffee producers are expected to enjoy higher prices this year thanks to falling output in Colombia, the world's third biggest exporter, the chief executive of the Ethiopia Commodity Exchange (ECX) said. "The outlook for Arabica prices seems to be they will continue upwards because of the shortfall of production in Colombia," Eleni Gabre-Madhin told Reuters late on Thursday. "We think this is a very good opportunity for African fine coffees."