Swimming remains the No. 1 participation sport in the UK, but perhaps due to the recession, U.S. participation decreased last year, according to two recent reports.

The Sporting Goods Manufacturers Association recently released its Single Sport Participation Studies and found that swimming, for competition or fitness decreased 8.5 percent last year. In 2009 there were 17,443 study participants who were competitive or fitness swimmers, compared with 19,041 in 2008.

Other water sports also showed a decrease, including aquatic exercise (-6.5 percent), surfing (-7.8 percent), canoeing (-7.6 percent), jet skiing (-18.5 percent), recreation kayaking (-0.4 percent), Scuba diving (-36.7 percent).

This study was a joint effort of The Physical Activity Council, Sporting Goods Manufacturers Association, Tennis Industry Association, National Golf Foundation, IHRSA, Snowsports Industries America, The Outdoor Foundation, and the United States Tennis Association. Data was collected from 40,141 online interviews were carried out with a nationwide sample of individuals and households during January and February of 2010.

Similarly, the National Sporting Goods Association telephone survey of 10,000 households found that swimming participation decreased 6.1 percent. Last year, a total of 50.2 million individuals participated more than once.

The NSGA reports that swimming was the No. 4 sport in 2009, behind Exercise walking (93.4 million participants), exercising with equipment (57.2 million), and camping (50.9 million).

Experts say the shift downward may be part of a larger trend, but it may also be a function of the economy.

“Swimming has always been among the most popular activities,” said Larry Weindruch, NSGA director of communications. “It was No. 1 until about 20 years ago, when exercise walking moved up. Swimming has slowly declined since then.”

However, NSGA documents an upturn for the past few years and the SGMA reports an 8 percent increase in swimming for fitness/competition.

“Aquatics sports have probably been more impacted by the economy and rising fuel prices than most sports, athletic or recreational activities,” said Mike May, SGMA director of communications. “… still, those who participate in aquatics are often passionate about their sport and make participation in them a priority.”

May also notes that for some, access to water can be a barrier to participation and that presents a growth challenge for some aquatic activities.

Industry leaders point out that aquatics is one of many activities that saw a decrease in participation last year.

“When you compare the swimming numbers to other major sports, swimming isn’t doing too badly,” said Alex Antoniou, Ph.D., director of educational programs.

Time spent consuming entertainment products may be one reason for the decrease in participation in physical activity and recreation, notes Bruce Wigo, CEO of the International Swimming Hall of Fame, in Fort Lauderdale, Fla.

Meanwhile, across the Atlantic, Sport England’s Active People survey found nearly 3.26 million Brits swim regularly, a number that represents significant growth.