Photo/Illutration Yoshiki Nitta, president of The Cordvan & Co., shows off leather goods using black bass skin and dyed with waterweed from Lake Biwako in Otsu in March. (Hirokazu Suzuki)

OTSU--New specialties have been born from the collaboration of two nuisances in Lake Biwako.

Leather goods were developed using the black bass, an alien species which exerts a negative impact on the lake’s ecosystem, and water plants growing in large numbers to hinder the navigations of fishing boats.

Though they are priced mainly between 20,000 yen ($183) and 50,000 yen, bass anglers and others are showing interest in them.

The new products include wallets carrying price tags of 35,200 yen to 52,800 yen as well as a 33,000-yen key case and a change purse with a price of 26,400 yen.

They all use the carefully tanned skin of the black bass from Biwako and dyed with an agent based on waterweed from the lake.

Wallets made using black bass skin and dyed with waterweed from Lake Biwako are shown at the Shiga prefectural government office. (Hirokazu Suzuki)

“The scales create peculiar patterns,” said Yoshiki Nitta, president of The Cordvan & Co., a horsehide goods maker in Himeji, Hyogo Prefecture, which developed the products. “One can enjoy seeing the products’ color and hardness changing over time like other leather goods.”

Nitta, 50, came up with the idea of using the durable black bass skin for leather items because he loves fishing the bass.

The species’ flesh is consumed as food, but its skin is normally discarded. Nitta procured the black bass skin from a fishermen’s cooperative.

The skin was unscaled and tanned, while oil and other impurities were removed with a unique technology so that the fish could turn into wallets and other articles.

The products were marketed in 2017, selling more than 200 units annually. This made Nitta “sense a good response” from consumers.

While they have been treated by chemical dyes, Nitta wanted to “create products friendly to nature.” He tested multiple water plants in Biwako for dyeing.

Working with Otsu-based WEF Institute of Technology Inc., which works for water purification, Nitta completed the waterweed powder processed by active oxygen for botanical dyeing.

The new products are being delivered to order. Samples are shown at leather goods store TWCM Ema Osaka in Osaka’s Kita Ward and the main outlet of the Rogues select shop in Konan, Shiga Prefecture.