As go the palace moats so goes the country: black bass and bluegills have invaded most ponds and lakes on this island nation. Aside from being big and ugly, the fish are wreaking considerable havoc on local ecosystems. They eat the babies of many native Japanese fish, threatening the survival of several species, such as tanago and honmoroko. Earlier this year the Japanese government declared war on the invaders. It formed a panel of experts to analyze the situation and come up with strategies to eliminate the fish. So far little’s been done, and the aliens continue to win the war of attrition.
Japan’s woes began in 1925 when Tetsuma Akahoshi, a businessman with a fondness for game fishing, brought over 90 black bass from California. Bluegills were reportedly a gift to the crown prince (now the emperor) by the mayor of Chicago in 1960. Nobody knows how the fish wound up in the palace moats, but their spread throughout Japan probably had something to do with the rise of game fishing in the 1970s. Unlike many native species, black bass and bluegills go for lures, which makes them a favorite of the fishing-tackle industry. Millions of Japanese were persuaded to drop their lures into the country’s hundreds of lakes and ponds. Rather than taking home their catch and eating it, they tended to throw the fish back in the water. The aliens returned the favor by devouring baby shrimps, smelts and eels. As publishing houses brought out dozens of books on black-bass fishing and magazines ran a constant stream of articles on the craze, black bass and bluegills multiplied. “The fishing-tool industry was behind the black-bass boom,” says Tomosuke Noda, an outdoor writer.
A visit to Lake Biwa reveals just how bad things have become. Japan’s largest lake, at 670 square kilometers, used to be filled with native clear-water fish like shrimp, crucian carp and willow gudgeon, but in recent years these populations have fallen. The native catch dropped from more than 8,000 tons in 1972 to 2,174 tons in 2000. Meanwhile experts estimate that the tonnage of black bass and bluegills now exceeds 3,000. In October, the local Assembly voted to ban fishing enthusiasts from releasing their catch back into the water. The local fisheries cooperative is offering to turn the catch into chicken feed.
Even less is happening on the national level. The National Federation of Inland Water Fisheries Cooperative Association put out a brochure explaining how the fish destroy the ecosystems and suggesting some recipes (black bass cooked in chili sauce), but executive director Minoru Sato admits that more drastic measures are called for. “We need to restore the ecological order before it’s too late,” he says. A government survey shows that three quarters of Japanese people favor a large-scale effort to exterminate the imported species.
“I used to catch 20 kilograms of shrimps on a good day,” says Ikuo Sato, a 72-year-old fisherman standing at Lake Izunuma. “I now see just a couple of them in my net–a pitiful sight.” Sato mourns the loss of ebimochi, a dish of pounded rice and lake shrimp, seasoned with soy sauce. “I feel sad every time my family makes our old favorite dish,” Sato sighs. “These days, we have to use packaged shrimps bought from shops.”
