Study

Induced ovulation by injection of 17, 20β-Dihydroxy-4-pregnen-3-one in the artificially matured Japanese eel, with special reference to ovulation time

  • Published source details Kagawa H., Tanaka H., Ohta H., Okuzawa K. & Iinuma N. (1997) Induced ovulation by injection of 17, 20β-Dihydroxy-4-pregnen-3-one in the artificially matured Japanese eel, with special reference to ovulation time. Fisheries Science, 63, 365-367.

Actions

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 study in 1994–1996 at a research facility in Japan (Kagawa et al. 1997) found that artificially fertilized Japanese eel Anguilla japonica eggs had variable fertilization and hatching rates in each of two experiments, and rates did not differ significantly when donor females were injected with hormones in the morning or evening. In the first experiment, an average of 2–54% of eggs/female were successfully fertilized, and 0.3–40% of eggs/female hatched. Eggs from females injected with hormones in the morning had similar fertilization (13%) and hatching rates (10%) to those from females injected in the evening (fertilization: 9%, hatching: 7%). In a second experiment, average fertilization rates were 3–63%, and hatching rates were 1–55%. In each of two experiments, captive-reared female eels were injected with salmon pituitary extract followed by a hormone (17,20β-dihydroxy-4-pregnen-3-one) to induce ovulation. Hormone injections were given at 9:00 h (15 eels) or 18:00 h (18 eels) in the first experiment, and at 18:00 h only (34 eels) in the second. In both experiments, eels were checked for ovulation every 3 h. Eggs were collected and mixed with diluted semen from a captive male. Samples (containing about 100 eggs) from each fertilization were placed in petri dishes with seawater, and incubated at 23°C. Average fertilization and hatching rates were estimated for three samples/female/treatment. 

    (Summarised by: Anna Berthinussen)

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