Japanese researchers conduct ultrasounds on whale sharks in the wild
  • Wednesday, February 20, 2019
  • 71°


Japanese researchers conduct ultrasounds on whale sharks in the wild


    WHAT A CATCH: A nearly 15-foot male whale shark swims in the Yokohama Hakkeijima Sea Paradise, where it was transferred into the park’s 26-foot tank in late August. The whale shark, which strayed into a fi shing net off Tateyama in Chiba Prefecture, will be released back into the sea when it grows to 18 feet.


An international team including researchers from the Okinawa Prefecture-based Okinawa Churashima Foundation and from Australia have for the first time successfully completed an ultrasound scan of a living whale shark’s ovary.

According to the foundation, which operates the Okinawa Churaumi Aquarium in the prefecture, the achievement could lead to artificially breeding the world’s largest fish, which can grow to over 33 feet in length.

Using an ultrasound device on the stomachs of whale sharks in seas off Ecuador in September, the team confirmed the presence of several follicles up to 3 inches long inside the ovaries of three females.

The species is on the International Union for Conservation of Nature’s Red List of Threatened Species.

In recent years, it has been discovered the fish delivers offspring after pups emerge from eggs inside its uterus. However, details of its reproductive process remain unknown.

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