DETERMINATION OF THEORETICAL PROLIFICACY OF THE DANUBE GUDGEON (GOBIO OBTUSIROSTRIS) FEMALE FROM NADRAG RIVER BASIN

I. Bănăţean-Dunea, M. Bura, A. Grozea, Silvia Pătruică, Valerica Murgoi

Abstract
In the existent literature, there is little information referring to theoretical prolificacy of the native fish species and for these reasons, knowing the following aspect is of paramount importance. The biological material under study has been made up by 30 females aged 3-4 years from the species Gobio obtusirostris that have been collected from the Nadrag river basin. The collection of samples for investigation has been done in the banned period through an electric fishing device Tyo FEG 3000. In order to find out the age of the biological material, the method of age interpretation according to fish scales has been used. Regarding the determination of theoretical prolificacy, the following aspects have been under study: the total length of the body, the body weight, the weight of the ovary, the body weight without the ovary, the number of spawns/ 0.10g and the number of spawns in the two ovaries. The average value of the total length at the female Danube Gudgeon body (Gobio obtusirostris), aged 3-4 years has been of 10.01±0.15 cm. The average of the body mass was of 10.59±0.42 g, and the average mass of the ovary was of 1.73±0.42 g. The average number of spawns obtained from the two ovaries of the Danube Gudgeon females aged 3-4 years has been of 6066±422, and the given variability was high (CV= 38.07%). The fertility coefficient at the Danube Gudgeon female (Gobio gobio obtusirostris) aged 3-4 years was of 0.0174.

Key words: Gobio obtusirostris, theoretical prolificacy, Nadrag river basin