* TSX down 81.59 points, 0.53 percent, to 15,290.76
* Six of the TSX's 10 main groups were down
TORONTO, May 31 (Reuters) - Canada's main stock index fell on Wednesday in broad declines, with a slump in oil prices dragging energy stocks lower.
Suncor Energy Inc slipped 1.0 percent to C$42.22. The energy group retreated 1.4 percent as oil prices hit a three week-low.
Benchmark Brent crude tumbled 3.1 percent to $50.21, hit by news that Libyan output was recovering from an oilfield technical problem.
At 11:57 a.m. ET (1557 GMT), the Toronto Stock Exchange's S&P/TSX composite index shed 81.59 points, or 0.53 percent, to 15,290.76.
Of the index's 10 main groups, six fell.
Asanko Gold Inc shares fell 13.2 percent to C$2.19 before being halted after short-selling firm Muddy Waters said it was shorting the stock due to concerns about the company's mining operations in Ghana.
Several other companies were hit amid speculation they were the target of Muddy Waters, which proved to be incorrect.
Element Fleet Management Corp plunged nearly 40 percent before being briefly halted. The stock was still down 7.7 percent at C$9.32 after trading resumed.
The company issued a statement saying it was unaware of any material information that would account for the move and heavy trading volume.
ECN Capital Corp was also halted briefly after tumbling nearly 20 percent. The stock was down 6.4 percent at C$3.54 after trading resumed.
Element Fleet provides management services for commercial vehicle fleets, and ECN Capital is an independent commercial finance company. The two companies were formerly known as Element Financial Corp before splitting last fall.
The materials group, which includes precious and base metals miners and fertilizer companies, lost 1 percent, with Teck Resources Ltd sliding 5.3 percent to C$23.96.
Cyclical stocks including financials and industrials also fell, even as government data showed that the Canadian economic growth accelerated strongly in the first quarter, growing at an annualized 3.7 percent pace.
The financials group slipped 0.4 percent. Industrials fell 0.3 percent.
Declining issues outnumbered advancing ones on the TSX by 174 to 71, for a 2.45-to-1 ratio on the downside.
Reporting by Solarina Ho Editing by W Simon