Unusual cases of adult intersexuality in the European eel Anguilla anguilla

• Published in: Sexual Development
• Main Authors: Geffroy, Benjamin, Fostier, Alexis, Guiguen, Yann, Bardonnet, Agnes
• Other Authors: Ecologie Comportementale et Biologie des Populations de Poissons (ECOBIOP), Institut National de la Recherche Agronomique (INRA)-Université de Pau et des Pays de l'Adour (UPPA), Laboratoire de Physiologie et Génomique des Poissons (LPGP), Institut National de la Recherche Agronomique (INRA)-Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique )
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2012
• Subjects: aromatase; european eel; hermaphrodite; intersex; [SDV.BA]Life Sciences [q-bio]/Animal biology; [SDV.BDLR]Life Sciences [q-bio]/Reproductive Biology; [SDE.MCG]Environmental Sciences/Global Changes; Anguilla anguilla
• Online Access: https://hal.inrae.fr/hal-02651152; https://doi.org/10.1159/000343781

International audience Two cases of intersexuality are reported for the first time in European eel, Anguilla anguilla (at the beginning of the silver eel stage), within 140 fish caught as glass eels in the south-west of France and reared in tanks at 17°C. Cysts containing spermatozoa were observed in ovaries with pre-vitellogenic oocytes. This feature is very uncommon, especially owing to the fact that male cells do not normally reach this stage in captivity, and an environmentally controlled transdifferentation process may not be excluded. Besides, the expression of the gonadal aromatase gene (cyp19a1a) was found to be higher in these 2 intersexual fish compared to normal females, although these results must be considered with caution since only 2 intersexual fish were available. A possible feminizing effect of this ‘abnormal’ upregulation of aromatase is discussed.