CAIRO, July 6 (Reuters) - Egypt’s main stock index fell by almost 2% on Tuesday, a dip that analysts linked to Ethiopia’s announcement that it had begun filling the reservoir behind its giant hydropower dam for a second year. Egypt’s main index was down 10,155 points, or 1.80%, at close of trading. “What’s happening are fear transactions by individual investors,” said Rania Yacoub, chair of the board of directors of Three Way Brokerage. “There are no other reasons for the decline except the Renaissance Dam.” Ethiopia says the Grand Ethiopian Renaissance Dam (GERD) on the Blue Nile is crucial to its economic development and providing power to its population while Egypt views the dam as a grave threat to its Nile water supplies. Egypt, as well as Sudan, had demanded that Ethiopia come to a binding agreement in advance of the second filling. Beltone shares dropped 6% and Pioneers Holding was down 4.9%, while El Sewedy Electric was down 3.9%, and Fawry was down 3.1%. Reporting by Ehab Farouk Writing by Malaika Tapper; Editing by Aurora Ellis Our Standards: The Thomson Reuters Trust Principles.