WINDERMERE, Fla. ( Stockpickr) -- Professional traders running mutual funds and hedge funds don't just look at a stock's price moves; they also track big changes in volume activity. Often when above-average volume moves into an equity, it precedes a large spike in volatility.>>5 Stocks Warren Buffett Loves Major moves in volume can signal unusual activity, such as insider buying or selling -- or buying or selling by "superinvestors." Unusual volume can also be a major signal that hedge funds and momentum traders are piling into a stock ahead of a catalyst. These types of traders like to get in well before a large spike, so it's always a smart move to monitor unusual volume. That said, remember to combine trend and price action with unusual volume. Put them all together to help you decipher the next big trend for any stock. >>5 Toxic Stocks to Dump Before 2013 With that in mind, let's take a look at several stocks rising on unusual volume today. Tortoise MLP Fund ( NTG) Under normal circumstances, the fund will invest at least 80% of total assets in equity securities of MLPs in the energy infrastructure sector, with at least 70% of total assets in equity securities of natural gas infrastructure MLPs. This stock is trading up 1.1% at $25 in recent trading. Today's Volume: 174,000 Average Volume: 109,885 Volume % Change: 232% From a technical perspective, NTG is bouncing modestly higher here right off its 200-day at $24.80 and just above its 50-day at $24.99 with above-average volume. This move is starting to push NTG within range of triggering a major breakout trade. That trade will hit once NTG manages to take out some near-term overhead resistance levels at $26.03 to $26.21 with high volume. Traders should now look for long-biased trades in NTG as long as it's trending above some near-term support at $23.77, and then once it sustains a move or close above those breakout levels with volume that hits near or above 109,885 shares. If that breakout hits soon, then NTG will set up to enter all-time high territory once it clears $26.21. Some possible upside targets are $30 to $32 if we get that breakout soon.