基于声学方法的黄河三门峡水库渔业资源空间分布研究

为探讨声学方法在黄河流域生态环境研究中的适用性,于2013年11月23日使用分裂式波束科学鱼探仪(Simrad EY60,70 k Hz,挪威)对黄河三门峡水库西湾至库尾大坝间水域进行了渔业资源声学调查,并通过现场鱼类目标强度测定和回波积分方法对库区内渔业资源密度、资源现存量和空间分布进行了初步探查与估算。结果表明:此次调查库区内声学积分值(Nautical area scattering coefficient,NASC)为5.59 m2/nmi2,渔业资源密度平均为0.002 ind./m2,资源现存量为42.36 t;在鱼类资源密度空间分布统计方面,将调查区域库区分为上、中、下游3个调查区域(A、B、C区),8个积分区段,依次为A-Ⅰ、A-Ⅱ、A-Ⅲ,B-Ⅰ、B-Ⅱ,C-Ⅰ、C-Ⅱ、C-Ⅲ区段,其对应的鱼类资源密度分别为0.002、0.017、0.013 ind./m2,0.004、0.008 ind./m2,0.013、0.016、0.037 ind./m2,鱼类资源主要集中于上游的A-Ⅱ、A-Ⅲ区段及水库下游区域;对应鱼类的垂直分布,A-Ⅱ、A-Ⅲ、C-Ⅰ、C-Ⅱ区段鱼类主要分布于5 m以浅水层,A-Ⅰ、B-Ⅱ区段鱼类主要分布于10 m以浅水层,而B-Ⅰ区段鱼类均分布于5 m以深水层且数量较少,C-Ⅲ区段鱼类则主要分布于10~20 m水层;库区内鱼类目标强度(Target strength,TS)多分布于-62.5~-47.5 d B之间,且目标强度大于-44.5 d B、体长大于25 cm的个体均分布于5 m以深水层。研究表明,声学方法在淡水水库渔业资源评估中体现出良好的适用性,本研究推动了该方法在黄河流域水域生态环境研究中的应用,为今后用声学方法评估内陆河流、湖泊和水库渔业资源提供了理论基础和科学依据。

Spatial distribution of fisheries resources in Sanmenxia Reservoir in the Yellow River based on an acoustic method

The fisheries resources were investigated from Xiwan to the reservoir dam in the Sanmenxia reservoir u-sing split-beam scientific echosounder (Simrad EY60,70 kHz,Norway)on November 23, 2013 to evaluate the uti-lization of an acoustic method in assessment of ecological environment in the Yellow Sea River basin. The density, standing crop and spatial distribution in different areas of fishery resources were explored and estimated primarily by fish target strength in situ and using of an echo integration method. The results showed that the acoustic integral value(Nautical area scattering coefficient,NASC) in the reservoir was 5. 59 m2/nmi2, the average density of fisher-ies resources 0. 002 ind. /m2 , and the size of fisheries resources 42. 36 t. The surveyed area in the reservoir was di-vided into upper, middle and lower reaches( A, B and C areas) according to the density spatial distribution of fish-eries resources, and the density of fisheries resources in the total of eight integral segments were followed by 0. 002 ind. /m2 in A-Ⅰ, 0. 017 ind. /m2 in A-II, 0. 013 ind. /m2 in A-Ⅲ;0. 004 ind. /m2 in B-Ⅰ, 0. 008 ind. /m2 in B-II and 0. 013 ind. /m2 in C-Ⅰ, 0. 016 ind. /m2 in C-II, and 0. 037 ind. /m2 in C-Ⅲ. The fisheries re-sources were heavily distributed in the upper reaches of A-II and A-Ⅲ segments and the lower reaches of reser-voir. Most fish stock in the segments of A-II, A-Ⅲ, C-II and C-II were vertically distributed in 5 m shallow water layer, and fish stock in the segments of A-Ⅰand B-IIwere primarily distributed in 10 m shallow water lay-er. As fish stock in B-Ⅰsegment was distributed in 5 m deep water layer with less amount, the fish stock in C-Ⅲsegment was largely distributed in the 10 m to 20 m water layer. The fish target strength in the reservoir was mostly distributed from -62. 5 dB to -47. 5 dB, and the individuals with target strength of greater than -44. 5 dB, and body length of over 25 cm were entirely distributed under 5 m water layer. The findings prove that the acoustic method reflects the favorable applicability at assessment of fisheries resources in freshwater reservoir, promoting the application of acoustic method in the study of ecological environment of fishing waters in the Yellow River, and pro-viding the theoretical foundation and scientific basic for further study on the acoustic assessment of fisheries re-sources in inland rivers, lakes and reservoirs.