Age, growth, and energy storage of the cavefish Triplophysa rosa

Abstract

Abstract Background The age, growth, and energy storage of Triplophysa rosa, a typical cavefish, were explored in this study. A total of 102 wild T. rosa were collected in Wulong County, Chongqing, China, from 2018-2022. The otoliths were used for age determination. Results The earliest mature individuals were 4.8 years old, and the maximum ages for both females and males were estimated to be 15.8 years and 12.2 years, respectively. The length (L, cm)-weight (W, g) relationship was the same for both sexes, i.e., W = 0.0046L3.03. The von Bertanlanffy growth models were fitted to the total length at age data with an asymptotic length of 23.4 cm and a value of the K-parameter of 0.060 year-1. This implies growth rates that are lower than those in the majority of previously reported other fish but within the range of values for other Triplophysa species. The body content of protein, ash, and glycogen did not significantly correlate with the total length of T. rosa. However, both lipid and energy content increased significantly with total length. The lipid (ranging from 40.5 to 167.1 mg g-1) and energy (ranging from 4.50 to 11.39 kJ g-1) contents indicate high storage features of T. rosa. Conclusions The results confirm that T. rosa has characteristics that make it suitable for survival in cave conditions, i.e., slow growth, small size, and high lipid energy storage.