Ecklonia cava, also called paddle weed, kajime (Japanese: 搗布[2]/未滑海藻), noro-kajime, or gamtae (Korean: 감태), is an edible marine brown alga species found in the ocean off Japan and Korea.

In fact, the standard common name for E. cava in modern-day Japanese is kajime (カジメ), to be distinguished from the wrinkled-leaved Eisenia bicyclis (syn.

[17] The algae determined to be kajime based strictly on morphology have been reported in Shikoku, parts of Kyushu, and southern coasts of the Sea of Japan,[26][18][22] but these tend to be the kurome or tsuruarame subspecies.

[27] As a brown alga, it plays an important role in the ecosystem and habitat of where it lives, providing a source of food and shelter for many marine organisms.

[16] Many factors could contribute to the decline, such as an increase in water temperature, overgrazing, and overuse by humans, but the direct cause of the decrease has not yet been extensively studied.

Ecklonia cava is an important food source for snails, such as Littorina brevicula (Philippi) and Haliotis discus (Hannai Ino), and other marine organisms.

The health benefits of Ecklonia cava and its chemistry have been somewhat studied, leading to its uses in dietary supplements and herbal remedies.

Though its health benefits are not yet entirely understood, it is also regularly touted as an herbal remedy for insomnia, hair loss, high cholesterol, asthma, and even erectile dysfunction.

[34] The arame in the loose sense (either E. cava or E. bicyclis) are known to have been trafficked in quantity at least since the Nara Period, as evidenced by wooden tags on transported good (mokkan) which have survived from the 7–8 centuries.

[33] In the processing of a more major food seaweed, Hizikia fusiformes (hijiki), portions of Ecklonia cava or Eisenia bicyclis (arame) are added in order to moderate the bitter flavor, as well as toning down the intensely dark (blackish) color.