Mr. Lin began cultivating fish at Mischief Reef in 2007. Mischief Reef, which has been controlled by China since 1994 but is part of the Spratly Islands in the South China Sea also claimed by the Philippines, Taiwan and Vietnam.Cultivating fish at Mischief Reef, called Meiji Reef by the Chinese, is equivalent to “safeguarding national sovereignty,” Mr. Lin was quoted as saying. “Because once there are residents there — us — it becomes our territory, according to international ocean law.”