In Toronto Canada, I've bought different BIG, raw scallop species like at Whole Foods Market. They are big like HK restaurants'. After I add oil to pan on cook top and stir fry them, they shrink. Why? See photos –
Now see HK restaurants' wok fried scallops Jade Scallops – 西蘭花炒帶子 in Chinese. Top to bottom – House of Canton in Kowloon Tong (first photo beneath),Ming Kee Restaurant in Wan Chai, 金龍冰室 in Tai Po 大埔, Joy Point Dim Sum in Tsim Sha Tsui.