Tahoe Lobster Co., the first commercial fishing operation to come to Lake Tahoe since the 1930s, drew national attention, but it's also worried some regional outfitters who say fish like the trout and mackinaw rely on the crawfish for food. Gene St. Denis, operator of Blue Ribbon Fishing Charters, started fishing Lake Tahoe in 1981. A trophy trout and light tackle specialist, St. Denis said 50 to 70 percent of the fish he reels in have crawfish in their stomachs. "They're a significant food source for the freshwater fish of Tahoe. Saying the crawdads aren't a primary food source for …