Fisherman in southwest Japan city cultivates Okinawa's sea grapes on land

ISAHAYA, Nagasaki -- In a remarkable feat, a 37-year-old fisherman named Goki Hirata has become the first person in Nagasaki Prefecture to cultivate sea grapes on land. Hirata, who primarily raises oysters and clams in Nagasaki's Konagaicho district, decided to venture into sea grape cultivation because these sea vegetables can thrive during the summer off-season, with a cultivation period of about one month.

Hirata started experimenting with sea grape growth three years ago within a warehouse at his home. Last year, with financial assistance from both the Nagasaki Prefectural Government and the Isahaya Municipal Government, he constructed a specialized facility for his cultivation efforts. Since early June, he has been selling the fruit-like seaweed for approximately 400 yen (around $3) per 60-gram container at the Konagai direct sales store run by the Isahaya Bay fisheries cooperative and at the 251 Iimori Jaga Road roadside rest stop. The sea grapes are also being incorporated into sushi dishes in Nagasaki.

The modest 30-square-meter facility houses 24 cylindrical tanks, each standing 140 centimeters tall and 42 centimeters in diameter. These tanks are filled with seawater sourced from the Konagaicho area. The water temperature in the tanks is kept between 26 to 30 degrees Celsius. LED lights remain on continuously, although Hirata acknowledges the challenge of adjusting lighting schedules to prevent the growth of diatoms, a type of algae.

Notably, on July 30, Isahaya Mayor Yukishige Okubo visited the facility. The mayor, who enjoys consuming sea grapes whenever he visits Okinawa, tasted the locally grown product and remarked, "The crisp, popping texture is great. It's delicious because it's fresh." Hirata has set a goal to ship 200 kilograms of sea grapes per month until the end of October. He hopes to expand production and establish sea grapes as a new, city-associated specialty of Isahaya during the summer months.