Preliminary results on the reproduction of a deep-sea snailfish Careproctus rhodomelas around the active hydrothermal vent on the Hatoma Knoll, Okinawa, Japan

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Tel.: +81 98 895 8993; email: takemura@sci.u-ryukyu.ac.jp

Abstract

Deep-sea snailfish Careproctus rhodomelas were collected from an active hydrothermal vent using a remotely operated vehicle (R.O.V. Hyper-dolphin) and a pressurized device (Deep-Aquarium). Careproctus rhodomelas exhibited a cystovarian-type ovary containing a small number of developing oocytes at different stages, suggesting that the fish is a batch-spawner that spawns large eggs (c. 6·0 mm) several times within its life span. In vitro culture of the oocytes in the presence of human chorionic gonadotropin showed that oestradiol-17β production fluctuated with oocyte development, suggesting that the oocytes were at the vitellogenic stage.

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