The Largemouth Invasion

The red banner on the side of the road read “brakku basu ryori.” Largemouth bass cuisine has come to Japan.

I saw a few banners like that as my friend and I were driving along the shore of Lake Biwa in Shiga Prefecture. I came to realize that largemouth bass, known in Japanese as brakku basu, is now being promoted as fish for eating in the area surrounding the biggest lake in Japan. I learned that the fisherman’s co-op, which is similar to a state fish and wildlife department in the US, is trying to promote “catch and keep or kill” by buying the bass from the anglers.

Largemouth bass is one of the biggest threats to the survival of the native fresh water fish species in Japan. Since the bass was imported from America and planted in Lake Ashinoko in the mid 1920s, they have spread all over the country because anglers release them, wanting to land the hard-fighting game fish instead. Without any compatible predators in the waters of Japan, largemouth bass have thrived. They now dominate the top of the food chain in Japan’s fresh water bodies.

The communities surrounding Lake Biwa, where people’s lives and culture were deeply dependent on the lake, were hit the hardest by the insurgence of the bass. Especially funazushi, known to be the oldest form of sushi in Japan, is having trouble sustaining production. Funazushi is made with nigoro buna, which is a carp species only native to Lake Biwa. The fish is salted first and fermented with rice and aged over a year for the pungent, blue-cheeselike aroma and flavor. I met a gentleman who told me how funazushi was made and consumed at each household. He also told me how plentiful the fish was when he was a child. But development and pollution damaged the fishery in recent years, and then the largemouth bass drove the species to near extinction.

Largemouth bass is just one of many elements that have hurt the fisheries plying in the nigoro buna trade, yet there are lessons to learn here. The very first bass was probably released into the lake by an angler who innocently wanted to fish for it there. He probably didn’t think that releasing the fish was going to change the fisheries, or that it would impact the ecosystem of the biggest lake in Japan. He certainly didn’t even imagine the many fishermen who had to give up fishing or the grandmothers who had to discontinue the family tradition of making funazushi because there aren’t any fish to make it with.

I am guilty as well. I once released a couple of largemouth and many bluegills into a pond near my family home in Kyoto. The invasive fish were probably already there, but I certainly didn’t think a thing about the ecosystem of the pond. I was ignorant, but not innocent.

Education is the key to protecting native species from invaders. The Great Lakes in America are facing a threat from the jumping Asian carp. Not to be outdone, Yellowstone cutthroat trout in Yellowstone Lake are threatened by the invasive lake trout from the Great Lakes. Anglers need to be aware of the consequences of their actions. Catch and release makes even more sense now.