MEXICO CITY, Nov 5 (Reuters) - In a switch to bolster marine conservation, Belize said Friday it settled its cash tender offer to purchase U.S. dollar bonds due in 2034 and redeem all bonds that were not tendered into the offer. Belize financed the purchase and the redemption of its bonds - an amount equal to about 12% of its gross domestic product - with funding from a subsidiary of The Nature Conservancy (TNC) as part of organization"s "blue" bonds program to conserve some of the world"s most vulnerable marine ecosystems. The settlement of the offer means Belize reduced the principal amount of its external debt by approximately $250 million, the government said in a statement. As part of the transaction, Belize"s government prefunded nearly $23.5 million to a marine conservation endowment account dedicated to supporting future marine conservation projects in the country. "Our expectation is that this transaction will pave the way for strong and long-lasting economic growth and allow Belize to achieve its marine conservation objectives," Belize"s Prime Minister John Briceno said in the statement. The TNC program uses private capital to refinance public debt of participating countries in order to support marine conservation efforts. Reporting by Cassandra Garrison in Mexico City and Bangalore newsroom; Editing by Kenneth Maxwell