LISBON, Aug. 29 (Xinhua) -- Portuguese ports saw cargo volumes fall by 4.8 percent in the first half of 2018 compared with the same period last year, the Mobility and Transport Authority (AMT) announced on Wednesday.

Ports in mainland Portugal processed 46.4 million tonnes of cargo between January and June, compared with the 48.6 million tonnes handled in the first half of 2017.

The fall is due to a drop in activity at Sines, by far Portugal's busiest port. Sines accounted for 50.2 percent of the total cargo volume for the year, but handled 9.9 percent less cargo than in the corresponding period in 2017.

Most significantly it saw a 14.6 percent reduction in transshipment volumes, whereby cargo is reloaded onto other ships or transferred to rail or road transport.

But it wasn't all bad news: Sines registered a 7.1 percent increase in hinterland traffic, which is when goods continue their journey on land through Portugal.

Sines is especially recognized for its transhipment capacity and is the only port in Portugal able to process container ships with a 20,000 TEU (20-foot equivalent units) capacity. On Aug. 3, its XXI Terminal welcomed its biggest ever ship, the 399-meter, 20,568 TEU capacity Madrid Maersk.

Portuguese ports handled 95.9 million tonnes of cargo in 2017, the country's record year.