LONDON, July 12 (Reuters) - Trading volumes at major cryptocurrency exchanges fell by more than 40% in June, research showed on Monday, with a regulatory crackdown in China and lower volatility among the factors depressing activity. Spot trading volumes fell 42.7% to $2.7 trillion, with derivative volumes down 40.7% to $3.2 trillion, London-based researcher CryptoCompare"s data showed. "Headwinds continued as China persisted with its crackdown on bitcoin mining," CryptoCompare said. "As a result of both lower prices and volatility, spot volumes decreased." Bitcoin , the largest cryptocurrency, fell more than 6% last month, touching its lowest since January, as authorities in China tightened restrictions launched a month earlier on bitcoin trading and mining. read more It had tumbled 35% in May, with its losses sparked by Beijing"s moves to rein in the fast-growing sector. Crypto trading volumes tend to spike during periods of extreme price swings. Major cryptocurrency exchange Binance, which has faced scrutiny from regulators across the world, retained its position as biggest platform by spot trading volume, CryptoCompare said. Still, volumes at Binance fell 56% in June to $668 billion. read more