EF-S 17-55/2.8 IS USM
These women are cleaning an aquatic vegetable commonly called "floating heart." I had the most difficult time finding the English name for this vegetable. It's not very commonly found, but it's grown in several places in Meinong, Kaohsiung. People usually just eat the stem, which can grow as long as 200cm. They're usually cut into 5cm long sections and then stir-fried. A little crunchy and quite fibrous (thus healthy, but not bad tasting). Since the stems are so long and difficult to clean, farmers get in chest waders and do the sorting and cleaning work in pools of water waist high.
This is probably one of the least tasty ways to eat floating heart: long and tied around a package of dumpling filling wrapped in a sheet of rice noodle.
Canon Kiss X3
EF 100/2.8L Macro IS USM
And a snippet of how it's harvested (at 2'04''):