Speaking during the monthly meeting of the Dubuque Racing Association Board of Directors, Aviles said revenues from companies like DraftKings and FanDuel are dwarfing the traditional gambling industry. The websites pose a threat to the future of casinos, he said.
"People have a finite number of discretionary dollars -- whether they spend it on entertainment or playing the lottery or gambling -- and now you have this big daily event that you can be part of," he said. "We would be very naive to think this does not come at a casino's expense."
A DraftKings employee recently was accused of using information compiled by his company to win $350,000 on rival daily fantasy sports site FanDuel. Aviles said some are calling that akin to "insider trading."
"This is the same kind of shenanigans that eventually outlawed online poker," Aviles said.
Fantasy sports gambling remains illegal in Iowa, but efforts to revisit this ban could be renewed in the Legislature next year.
Aviles said casinos must continue to lobby legislators on the status of fantasy sports betting. If the practice is approved, it is critical for lawmakers to classify it as "a game of chance and not a game of skill" so it is subject to the same oversight as other gambling activities, he said.
Aviles' comments came amid a slight bump in year-over-year casino revenues.
Revenue in the Dubuque market increased 2.1 percent in September, compared to the same month the previous year, thanks to a strong increase at Diamond Jo Casino.
Diamond Jo has 58.7 percent of the Dubuque market compared to Mystique Casino's 41.3-percent market share, according to DRA figures.
Diamond Jo generated revenue of $5.51 million in September, up from $5.01 million in September 2014. Mystique Casino saw its revenue slide from $4.2 million in September 2014 to $3.88 million last month.
Dustin Manternach, chief financial officer for Mystique Casino, said increased occupancy rates at Hilton Garden Inn and growing food and beverage revenues have served as bright spots in recent months for Mystique Casino.
Mystique Casino closed on the purchase of the Hilton Garden Inn and Houlihan's restaurant in June 2014.
"With the hotel and the food and beverage offerings we have now with the addition of Houlihan's, we are just trying to really promote that overall feel of the resort, full-service casino we have here," Manternach said.