#85 Is Wakame a Dangerous Invasive Species?
Red imported fire ants, redback spiders, common dandelions, red swamp crayfish, largemouth bass, alligator snapping turtles... Invasive species that pose dangers to human health or destroy Japan's ecosystems are frequently covered in the media. However, we must also be aware that invasive species originating from Japan are causing damage around the world.
That invasive species is 'wakame' (seaweed), which is very familiar to us.
Wakame is so commonly eaten that a product as counterproductive as 'Wakame Ramen without the noodles' has even been released.
However, wakame has been selected for lists such as the '100 of the World's Worst Invasive Alien Species' and the '10 aquatic organisms with significant environmental impacts,' making it a genuine nuisance overseas.
Wakame has high reproductive capacity and, in addition to destroying ecosystems, causes serious damage by clogging water intakes and hindering the growth of farmed shellfish and shrimp. Furthermore, the food culture of eating wakame is mainly found in East Asia; there is no such food culture in other regions, so wakame has become a seaweed that causes damage without even serving as food.
It is said that the cause of wakame spreading overseas is the 'ballast water' of tankers (*'ballast' means the weight loaded into the bottom of a ship). Tankers that have transported oil and other goods to Japan return empty. Since the ship's balance cannot be maintained in that state, they load seawater into ballast tanks to return home. It is believed that they took in wakame spores during loading and released them into the sea along with the seawater upon returning, leading to their proliferation.
Because this ballast water has the potential to transmit not only wakame but also other invasive species and infectious diseases, regulations are being advanced through treaties.
In addition to wakame, the plants 'kudzu' and 'Japanese knotweed' are listed among the '100 of the World's Worst Invasive Alien Species,' and insects that are common in Japan, such as the swallowtail butterfly and the Japanese beetle, are also causing damage as invasive species.
The invasive species problem is a 'mutual' issue. It is a problem that we must work together globally to address.
Reference