三峡库区重要支流8种优势鱼类生长及其资源开发现状评估

Assessment of the growth of eight dominant fish species and their resource development in important tributaries of the Three Gorges Reservoir area

根据2015年11月、12月和2016年5月、6月、9月三峡库区36条重要支流渔获物调查信息,基于FiSAT II软件对鲤(Cyprinus carpio)、瓦氏拟鲿(Pseudobagrus vachellii)、鲫(Carassius auratus)、蛇鮈(Saurogobio dabryi)、光泽拟鲿(Pseudobagrusnitidus)、?(Hemiculterleucisculus)、银鮈(Squalidusargentatus)和似鳊(Pseudobramasimoni)8种优势鱼类的生长及其资源开发现状进行了评估,旨在了解三峡库区重要支流鱼类资源变动趋势和生长情况,为该区域渔业管理和资源保护提供科学依据。结果显示, 8种鱼类生长指数(b)为2.74～3.11,近似等速生长;生长系数(K)大于0.2,为快速生长型;生长性能指数(φ?)为2.83～5.25;似鳊和鲫的资源开发率小于0.5,其余种类在0.5及以上;鲤、瓦氏拟鲿、蛇鮈、光泽拟鲿、?、银鮈的开捕体长分别控制在289 mm、253 mm、134 mm、102 mm、71 mm及52 mm以上,鱼类资源可得到有效恢复。研究表明,目前三峡库区重要支流鱼类资源开发过度;杂食性和肉食性鱼类生长速度呈加快趋势,而底栖动物食性鱼类呈减小趋势。

Accurate understanding of the changes in fish resources and growth characteristic in important tributar- ies in the Three Gorges Reservoir can provide a scientific basis for fishery management and resource conservation in the region. This study was based on fishery information collected in 36 important tributaries of the Three Gorges Reservoir area in November and December 2015 and May, June, and September 2016. The growth and development status of eight species of dominant fish was evaluated using the FiSAT II software developed by the Food and Agriculture Organization of the United Nations (FAO). These species were Cyprinus carpio, Pseudoba- grus vachellii, Carassius auratus, Saurogobio dabryi, Pseudobagrus nitidus, Hemiculter leucisculus, Squalidus argentatus, and Pseudobrama simoni. The growth and death parameters were estimated using the body length frequency distribution method (ELEFAN I), and the resource change trend was evaluated according to the Bever- ton-Holt model. The results showed the following. The body length and body weight of the eight species of fish were in a power function, and the growth index (b) was between 2.74 and 3.11, which is an approximate constant velocity growth. The growth coefficient (K) values of the eight species of fish were all greater than 0.2, which indicated a rapid growth type. The growth performance index (φ') was between 2.83 and 5.25, Cyprinus carpio was the highest at 5.25, and Squalidus argentatus was the lowest at only 2.83. The development rates of Pseudo- brama simoni (0.2) and Carassius auratus (0.4) were less than 0.5 and less than Emax;the development rates of the remaining six species were 0.5 and above. The length of the opening of Cyprinus carpio, Pseudobagrus vachelli, Saurogobio dabryi, Pseudobagrus nitidus, Hemiculter leucisculus, and Squalidus argentatus should be controlled at 289 mm, 253 mm, 134 mm, 102 mm, 71 mm, and 52 mm, respectively, and fish resources can be effectively restored. From these results, we can conclude that the development of important tributary fish resources in the Three Gorges reservoir area was excessive. The growth rate of omnivorous and carnivorous fish was increasing, but the benthic food fish were decreasing. We conclude that the upper reaches of the Yangtze River should focus on the protection of endemic species and the maintenance of biodiversity. Key waters should be forbidden from fishing throughout the year, so aquatic organisms can play out their ecological roles and improve the stability of the Yangtze River aquatic ecosystem.