Invasive Species Compendium

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Abstract

Gonad state and sex steroid hormones concentrations in invasive catfish (Loricariidae) from Vietnam.

Abstract

The gonads cytological state and the concentration of sex steroid hormones in the blood have been studied in the armored catfish of the genus Pterygoplichthys from three reservoirs of Central Vietnam (the Cái River, an irrigation canal connected with this river, and the Suôi Trău Reservoir). Females from the irrigation canal are characterized by more developed ovaries and intensive production of estradiol-17β from testosterone compared to females inhabiting the Suôi Trău Reservoir. Males from the irrigation canal were higher levels of estradiol-17β and testosterone compared to catfish inhabiting the reservoir. No significant anomalies have been found in the structure of the gonads, which indicates the successful adaptation of armored catfish to new water bodies.