Study

Milt Production in the Japanese Eel Anguilla japonica Induced by Repeated Injections of Human Chorionic Gonadotropin

  • Published source details Ohta H., Kagawa H., Tanaka H., Okuzawa K. & Hirose K. (1996) Milt Production in the Japanese Eel Anguilla japonica Induced by Repeated Injections of Human Chorionic Gonadotropin. Fisheries Science, 62, 44-49.

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This study is summarised as evidence for the following.

Action Category

Breed eels in captivity

Action Link
Eel Conservation in Inland Habitats
  1. Breed eels in captivity

    A replicated, controlled study in 1993 at a research facility in Japan (Ohta et al. 1996) found that captive male Japanese eels Anguilla japonica treated with a hormone (human chorionic gonadotropin) matured and produced sperm whereas untreated males did not, and sperm weight and gonad size were similar for two hormone concentrations. Male eels injected with human chorionic gonadotropin at two concentrations produced sperm (average total weight: 250 IU = 9 g/eel, 750 IU = 6 g/eel) and had developed gonads (gonad weight as a percentage of body weight: 250 IU = 10%, 750 IU = 8%), whereas untreated eels did not produce sperm and had undeveloped gonads (0.2%). Total sperm weights and gonad development were similar for the two hormone concentrations, although the results were not statistically tested. In May 1993, male eels purchased from a commercial supplier were tagged and held in 1,000-l tanks. Eels were injected 14 times weekly with a hormone (human chorionic gonadotropin at concentrations of 250 or 750 IU/eel/week; 7–10 eels/treatment) or a saline solution (eight eels). Two days after each injection, sperm was collected and weighed. Two days after the final injection, all eels were euthanized and gonads weighed. 

    (Summarised by: Anna Berthinussen)

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