COMPARISION OF CRITICAL SWIMMING SPEEDS BETWEEN WILD AND FARMED GYMNOCYPRIS PRZEWALSKII AND ITS RELATIONSHIP WITH PHYSICAL SIGNS

The swimming ability of fish significantly influences their survival, reproduction, and adaptation to the environment. The differences between aquaculture environment and natural habitat may affect fish swimming capabilities. To explore the differences in swimming ability between wild and farmed Gymnocypris przewalskii, as well as the correlation between swimming ability and physical characteristics, this study focuses on Gymnocypris przewalskii and employs a swimming tunnel device along with the flow rate increasing method to determine the critical swimming speed of both wild population and artificially bred 1st, 2nd, and 3rd age populations. The results showed that the absolute critical speed of the wild group (76.17±5.42) cm/s was not significantly differ from that of the cultured 1-year-old group (74.59±7.75) cm/s and the cultured 2-year-old group (77.58±4.16) cm/s (P>0.05), but was significantly lower than that of the cultured 3-year-old group (85.99±7.70) cm/s (P<0.05), There is no significant difference in the absolute critical swimming speed between the 2-year-old group and the 3-year-old group (P>0.05). Furthermore, the relative critical swimming speed of the wild group (3.11±0.38) BL/s was significantly lower than that of the cultured 1st age (7.10±0.83) BL/s, 2nd age (4.86±0.26) BL/s, and 3rd age group (4.78±1.37) BL/s (P<0.05). The relative critical swimming speed of the cultured 1st age group was significantly higher than that of the cultured 2nd and 3rd age groups (P<0.05), with no significant difference observed between the cultured 2nd and 3rd age groups (P>0.05). Regarding the relationship between critical swimming speed and morphological characteristics, absolute critical swimming speed is not significantly correlate with total length, body length, head length, body height, body thickness, tail stem length, tail stem height, and body weight. However, relative critical speed is significantly negatively correlated with morphological characteristics. In conclusion, at the same age, farmed Gymnocypris przewalskii exhibit stronger swimming abilities compared to wild populations. The results provide a scientific basis for the artificial breeding management of Gymnocypris przewalskii and the construction of fish passage channels.