Toronto's main stock index was lower on Monday morning on worries about the impact of the devastating earthquake and tsunami in Japan, which killed at least 10,000 people. Japan scrambled to avert a meltdown at a stricken nuclear power plant on Monday after a hydrogen explosion at one reactor and the exposure of fuel rods at another. [ID:nL3E7EC0D6] Uranium producers were among the biggest net decliners on the TSX as uncertainty over the future of the nuclear energy industry in Japan and elsewhere mounted. "Obviously, we come out of the gate a little bit weaker. The usual suspects are those who you would expect to be weak," said Paul Taylor, chief investment officer at BMO Harris Investment Management. Shares of top Canadian uranium miner Cameco Corp (CCO.TO: Quote) tumbled 17 percent to C$30.19, Uranium One (UUU.TO: Quote) sank 26 percent to C$4.44 and Paladin Energy (PDN.AX: Quote) sold off 21 percent to C$3.67. [ID:nWEN9501] "This does cause some potential buyers to question ... the safety of nuclear as part of the overall energy cocktail," added Taylor. "Obviously we do not know the extent to which the issues in Japan will accelerate, but certainly this doesn't bode well for the demand for nuclear." Energy shares slipped 0.5 percent after oil dropped to two-week lows, with prices underpinned by continued unrest in North Africa and the Middle East. [O/R] Suncor Energy (SU.TO: Quote) lost 1.2 percent to C$41.76 and Canadian Natural Resources (CNQ.TO: Quote) fell 1 percent to C$44.71. At 10:20 a.m. (1420 GMT), the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE was down 82.16 points, or 0.6 percent, at 13,592.09. Eight of the 10 main sectors were lower, including financials, off 0.3 percent. Insurers were lower due to some of their reinsurance exposure in Japan, said Taylor. Manulife Financial (MFC.TO: Quote) fell 2.3 percent to C$16.96, while Sun Life Financial (SLF.TO: Quote) was down almost 2 percent at C$29.71. Base-metal miners were down 1.4 percent on the near-term impact the Japanese disaster may have on the country's manufacturing industries. Teck Resources (TCKb.TO: Quote) was among the biggest decliners, down 3.6 percent at C$49.08. [MET/L] "People see ... the scale of the destruction and they're focusing on the shorter-term impact of the electronics and auto industries in Japan effectively coming to a complete standstill." Helping to limit the broader losses, gold miners were up 0.2 percent, supported by the safe-haven appeal of the precious metal, which neared record highs.