基于渔业声学调查的珠江东塔产卵场鱼类栖息地适宜性研究

Fish habitat suitability analysiSof Dongta spawning ground of Pearl River based on fisherieSacoustic survey

东塔产卵场是珠江最大的鱼类产卵场,同时也是多种珍稀特有鱼类的重要栖息地,对维持珠江中下游鱼类早期资源的补充及其多样性至关重要。为评估东塔产卵场鱼类的栖息地适宜性,基于2016—2019年的声学数据,通过热点分析,筛选出鱼类适宜分布的区域。以地形因子水深、坡度、坡向为栖息地指示因子,建立各因子适宜度指数范围,进而采用几何平均值法建立栖息地适宜性指数(Habitat suitability index,HSI)模型,并计算研究江段的HSI值。结果显示,东塔产卵场鱼类密度分布介于0.009~0.057尾·m^(−3);在时间上,鱼类密度呈逐年下降趋势,在空间上,鱼类分布整体自相关性不强,部分区域局部自相关性强,如产卵场沙洲邻近区域三年结果均为“热点区域”,大藤峡水利枢纽下游及石咀段出现“冷点区域”。该江段鱼类的适宜水深范围为5~8 m,适宜坡度范围为1.0°~1.5°(微斜坡),适宜坡向范围为90°~180°(东南方向)。通过HSI模型计算,得出研究江段HSI值介于0.02~0.95,平均值为0.31±0.22,高值区域集中出现在东塔产卵场的沙洲两侧,河流两侧也有零星分布,可能为鱼类潜在的适宜栖息区域;主航道基本为HSI低值区。利用2017年声学调查数据对HSI模型进行了验证,鱼类资源密度与HSI值呈线性正相关关系,表明该模型可较好地预测东塔产卵场的鱼类栖息情况,可用于江河鱼类栖息地适宜性分析与评价。

ASthe largest spawning ground,the Dongta spawning ground iSan important habitat for many rare and unique fish in the Pearl River,playing an important role in maintaining the supplement and diversity of early fish resourceSin the middle and lower reacheSof the Pearl River.In order to evaluate the fish habitat suitability,we selected the suitable habitat of fish by a hot spot analysiSbased on the acoustic data from 2016 to 2019.Taking the terrain factorS(Water depth,slope and aspect)as habitat indicatorSto calculate the fitnesSindex range of each factor,we established the habitat suitability index(HSI)model by using the geometric mean method and calculated the HSI value.It iSshowed that the fish density ranged from 0.009 to 0.057 ind·m^(−3) in Dongta spawning ground.In termSof time,the fish density had been decreasing year by year,but in termSof space,the overall autocorrelation of fish distribution waSnot strong,while the local autocorrelation waSstrong in some areas.For example,the area adjacent to the spawning ground sandbar had been a hot spot in three years,and the"cold spot area"appeared in the downstream of the Datengxia Water Project and Shizui Section.The most suitable water depth range waS5–8 m,the suitable slope range waS1.0°–1.5°(Micro-slope),and the suitable aspect range waS90°–180°(Southeast direction).The average HSI value waS0.31±0.22,ranging from 0.02 to 0.95,and the high value waSobtained mainly on both sideSof the sandbar of the Dongta spawning ground but scattered on both sideSof the river,where might be potentially suitable habitat areas.The main channel waSbasically the area with low HSI values.The HSI model waSverified based on the acoustic data in 2017,and the fish density and HSI showed a linear positive correlation,which indicateSthat the established model in thiSpaper can be used to analyze and evaluate the habitat suitability of river fish.