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Green tiger prawns cultivated from eggs for first time in east Japan

This photo provided by the Kanagawa Prefectural Fisheries Technology Center shows a larva of a green tiger prawn which grew as long as 9 millimeters in length 20 days after it was born.
An adult green tiger prawn is shown in this image provided by the Kanagawa Prefectural Fisheries Technology Center.

YOKOSUKA, Kanagawa -- The Kanagawa Prefectural Fisheries Technology Center announced that it has successfully raised green tiger prawns from eggs for the first time in eastern Japan.

    Although the young prawns died around one month after hatching, the center said that green tiger prawns can be seen as a promising species for fish farming.

    The Kanagawa Prefectural Fisheries Technology Center based in the prefectural city of Miura has engaged in cultivating sea animals while selecting suitable species in preparation for a change in the marine environment due to rising sea temperatures caused by global warming. From 2016, the center began developing technology for producing green tiger prawns, which inhabit the warm sea south of the Boso Peninsula, to release later in waters as part of fish stocking, or use in aquafarming.

    Green tiger prawns, one of the largest species of nektonic shrimp in Japan, belong to the same group as Japanese tiger prawns, and large ones can develop to a full body length of 30 centimeters. The market value of green tiger prawns is high, as they are used in dishes including tempura, and also served as grilled and enjoyed as sashimi, among other items.

    Although several hundred kilograms of green tiger prawns have been caught annually in Tokyo Bay through the small bottom trawling net fishing method, the specific nature of how it lives had not been uncovered. Therefore, the center had put to practical use the technology of cultivating Japanese tiger prawns, which have already been raised by aquafarmers in areas across western Japan.

    The spawning season for green tiger prawns is from late June to July. The center had been handed over captured green tiger prawn from a fisheries operator and succeeded in collecting an egg for the first time in 2019. However, the prawn died in less than a week. In July 2020, during the fifth year since the center started experimenting with raising tiger prawns, the center confirmed that three larvae hatched from the eggs. Green tiger prawns, which develop in warm waters, are mass produced in prefectures including Wakayama, Kochi, and Kumamoto in western Japan. However, this latest development apparently marks the first successful case of cultivating the sea creature in eastern Japan.

    Although the three larvae all died in August due to a deterioration in water quality in the container holding the prawns, the center said that it gained confidence in raising them. Yukinori Tonami, head of the fisheries center said, "Due to global warming, Tokyo Bay is gradually turning into an environment that is easy to inhabit for green tiger prawns, which are a warm water sea animal. We would like to keep making progress in technology development for mass production, and be able to cultivate the prawns to reach adult form next year."

    (Japanese original by Nobumichi Iwasaki, Yokosuka Local Bureau)

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