Estimates of the Age, Growth, and Mortality of Triplophysa scleroptera (Herzenstein, 1888) in the Upper Reaches of the Yellow River, China

Abstract

To investigate the age composition, growth pattern, mortality, and exploitation rate of Triplophysa scleroptera in the upper reaches of the Yellow River, we measured the total length (L) and body weight (W) of 347 individuals based on three sampling surveys from 2022 to 2023. The otoliths were used in this investigation to determine age. The total length of the collected samples ranged from 5.69 cm to 18.40 cm, body weight ranged from 1.65 g to 50.22 g, and the age ranged from 1 to 7 years old. The relationship of total length and body weight was W=0.009L2.942 for the total samples, and the growth pattern observed in the study belongs to the isometric type. The von Bertalanffy growth equation revealed that the fish had an asymptotic total length L∞ of 37.536 cm, and the growth coefficient K was 0.064 yr−1. Total instantaneous mortality rate (Z) of total samples calculated by the age-based catch curve method was 1.092 yr−1. The average instantaneous rate of the natural mortality (M), estimated by three different methods, for the total samples was 0.237 yr−1. The instantaneous rate of fishing mortality (F) for the total samples was calculated as 0.855 yr−1, and the exploitation rate (E) was determined as 0.783. As a whole, compared with other Triplophysa fishes, the growth rate of T. scleroptera in the upper reaches of the Yellow River is relatively slow, and the population of T. scleroptera has been overexploited. It is crucial to establish some effective management strategies to protect this species.

Age, Growth, and Mortality of Pontic Shad, Alosa immaculata Bennett, 1835, in the Danube River, Romania

“…Research on fish communities has an important role in the sustainable management of fishing practices. The estimation of growth and mortality population parameters, such as asymptotic length (L ∞ ), growth coefficient (k), mortality rates (Z, M, F), and exploitation levels (E), are important tools in understanding the biological characteristics of fish species, serving also as a basis for the good management and the preservation of aquatic resources [29][30][31].…”