The Pa Boeuk, one of the biggest fish in the Mekong, is a Silurian reaching a length of two meters and can weigh up to 300 kg. Pa Boeuk fishing was practiced between the 6^th and 7^th months. Its roe was much appreciated by the Laotian who used it to prepare Laotian caviar, called Somme khay. (Pavie, 1890, T6/135)