31 and 50 mm in length (48.3%). In Nam Pe, shells were harvested by villagers and the maximum
frequency of dead mussels was in the large size class of 81–100 mm (49.4%).
The youngest mussels found alive were four years old with mean length 34.4 mm from the Nam
Long River and 38.6 mm from the Nam Pe River. A 36.8-mm empty shell of the same
approximate age was found in the Nam Long River. Only six other specimens