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In 2007, the number of prince fish was about 25 million. Added to the bass, which was brought from the United States for sport fishing in the 1970s, the invaders represented 90% of the entire Lake Biwa fauna, which included 30 species of native fish. In 2005, the Shiga prefectural government spent R$ 6.64 million to remove 420 tons of invasive fish from the lake. Thanks to continued government-sponsored commercial fishing, the population has since halved, but bluegill perch and bass remain in the lake where traditional gillnets fail to catch smaller fish. In the past three years, eradication initiatives have cost the provincial government R$1.5 million annually. If fishing stops, the number of perch fish will rise again. |
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“the number of environments It appears to have decreased somewhat, and the population size in large bodies of water like Lake Biwa has decreased since 2005, but the distribution does not appear to have decreased,” Kawamura notes. “I have no hope.”
A solution may not be achieved
Finally, technology can offer a solution. Ongoing research led by Hiroyuki Okamoto, a fish geneticist, is focusing on “gene-induced inhibition in invasive populations” through the Crispr-Cas9 gene-editing tool. Okamoto’s team sequenced the bass genome and recently produced the first generation of male fish that can carry a female-specific sterile gene to the wild bass population, eliminating their ability to produce eggs. The program is in its sixth year in the laboratory. |
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