* TSX down 52.75 pts, or 0.4 pct, at 11,612.95 * Energy shares fall with oil prices * Worries about Spain rattle markets By Jon Cook TORONTO, July 20 (Reuters) - Canada's main stock index fell on Friday as energy shares retreated with oil prices and rising Spanish bond yields sparked fresh concerns over Europe's debt crisis. Nearly all of Canada's 10 main sectors moved lower. The powerhouse oil and gas subindex led the way, falling 1.1 percent as U.S. August crude eased after hitting a two-month high on Thursday. "Our market has been going up and down with the price of oil," said Brendan Caldwell, president and chief executive of Caldwell Investment Management Ltd. Energy declines were led by Canadian Natural Resources , down 1.1 percent to C$28.66, Cenovus Energy, which dropped 1.8 percent to C$32.35, and Suncor Energy slid 1 percent C$30.30. At 10:30 a.m. EDT (1430 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 52.75 points, or 0.4 percent, at 11,612.95. The index was on track for its first loss after rising the past five sessions. "The medium-term trend is for lower commodity prices and it will be until the worldwide economic situation is sorted out," added Caldwell. Global stocks were rattled on Friday after Spain's heavily indebted Valencia region called for aid, increasing investor doubts that the Spanish government can avoid a full-blown bailout. Spanish 10-year bond yields climbed back above the 7 percent threshold considered unsustainable, despite Euro zone finance ministers signing off on a 100 billion euros ($122.61 billion) bailout deal to recapitalize Spain's banks. Canada's financial services sector slid 0.5 percent on the shaky euro zone outlook. Losses were led by the major banks, with Royal Bank of Canada falling 0.7 percent to C$52.28, Bank of Nova Scotia down 0.9 percent at C$52.15, and Toronto-Dominion Bank slipping 0.6 percent to C$80.04. In earnings news, shares of West Fraser Timber Co Ltd jumped 2.4 percent to C$52.15 a day after the lumber company reported a second-quarter profit, on high lumber prices and strong demand from Asia.