The current study focused on the Wallago attu (freshwater shark) population dynamics parameters and examined them using monthly length frequency data that were gathered from the Bhadar Reservoir in Gujarat, India, between July 2018 and February 2019. To assess the total length (TL) and weight (W) of W. attu, 328 specimens total were collected. The estimated TL and W ranged from 31.5 cm to 109.5 cm and 28g to 5200g, respectively. For both sexes, the length-weight association was W=0.001 L=3.299 with R2 = 0.987. The parameters for the von Bertalanffy growth function were L=96.39 cm and K=0.71 yr-1. The growth performance indices for L∞ and W∞ were computed as Ø' = 3.819 and Ø=1.247 respectively. At an average yearly water surface temperature of 28°C, the natural mortality rate was 1.03 years per one. The overall instantaneous mortality was 1.00 years-1, with a 95% confidence interval of 1.05 to 1.42 (r2=0.987). The present exploitation ratio is -0.03yr-1, and fishing mortality was -0.03yr-1. The recruitment process continued all year, with a significant surge occurring in (June-July) at 17.22-18.90 percent. FiSAT-II examined the Beverton-Holt yield per recruit model; the maximum exploitation rate (Emax) was 0.94, E 0.9's calculated value was 0.10. The degree of exploitation, which will cause a 50% drop in B/R compared to virgin biomass (E0.2), was 0.78. Gulland (1971) said that E values above 0.5 indicate the overfishing of a species in an area. The exploitation rate, E=0.59, was less than the E-max (0.94) and suggested the fish was under-harvested in the Bhadar reservoir

Fish, Bhadar reservoir, Asymptotic length, Growth, Mortality

Using monthly length frequency data that were collected from the Bhadar Reservoir in Gujarat, India, between July 2018 and February 2019, the current study focused on the Wallago attu (freshwater shark) population dynamics factors and investigated them. 328 specimens in total were gathered to measure the total length (TL) and weight (W) of W. attu. The estimated TL and W ranged from 31.5 cm to 109.5 cm and 28g to 5200g, respectively. For both sexes, the length-weight association was W= 0.001 L= 3.299 with R2 =0.987. The parameters for the von Bertalanffy growth function were L= 96.39 cm and K= 0.71 yr-1. The growth performance indices for L∞ and W∞ were computed as Ø'= 3.819 and Ø= 1.247 respectively. At an average yearly water surface temperature of 28°C, the natural mortality rate was 1.03 years. The overall instantaneous mortality was 1.00 years-1, with a 95% confidence interval of 1.05 to 1.42 (r2= 0.987). The present exploitation ratio is -0.03 yr-1, and fishing mortality was -0.03 yr-1. The recruitment process continued all year, with a significant surge occurring in (June-July) at 17.22-18.90 percent. FiSAT-II examined the Beverton-Holt yield per recruit model; the maximum exploitation rate (Emax) was 0.94 and, E 0.9's calculated value was 0.10. The degree of exploitation, which will cause a 50% drop in B/R compared to virgin biomass (E0.2), was 0.78. Gulland (1971) said that E values above 0.5 indicate the overfishing of a species in an area. The exploitation rate, E=0.59, was less than the E-max (0.94) and suggested the fish was under-harvested in the Bhadar reservoir

N.A. Pargi and Hari Prasad Mohale (2023). Population Dynamics of Freshwater Shark (Wallago attu, Bloach Schneider 1801) from Bhadar Reservoir of Gujarat, India. Biological Forum – An International Journal, 15(12): 494-499.