noun
blue swimming crab; flower crab; blue manna crab
Refers to the species Portunus pelagicus, a common edible crab in East Asian waters. The katakana form is standard in Japanese.
タイワンガザミはワタリガニの一種で、食用として人気がある。
The blue swimming crab is a type of swimming crab and is popular as food.
ワタリガニ is a broader term for swimming crabs (family Portunidae), while タイワンガザミ specifically refers to Portunus pelagicus.
The name タイワンガザミ literally means 'Taiwan crab', likely referring to the region where it is commonly found. The exact derivation is uncertain.