泸沽湖特有水生生物的保护初探

2018年8月15—19日，利用Lowrance elite-7 Ti回声探测仪首次对云南省泸沽湖展开鱼类空间分布及资源量评估。调查采用“之”字形航线对泸沽湖全湖进行水声学探测，累计航程42.71 km，基于深度变化值将探测水体分为若干探测单元进行鱼类资源评估，并运用反距离插值法 (IDW) 基于各单元密度绘制进行空间分布图。水声学探测结果表明，泸沽湖鱼类空间分布不均匀，水平方向上，鱼类主要集群分布于近岸环形水域，其中小渔坝附近水域鱼类密度最高，湖心区域鱼类密度最低；垂直方向上，鱼类在表层水域分布较为集中；2018年8月泸沽湖鱼类密度为0.153尾·(1 000 m³)⁻¹，数量24.39万尾，总资源量50.55 t；其中，鲫 (Carassius auratus) 21.17万尾、17.36 t，鲤 (Cyprinus carpio) 1.74万尾、23.01 t，草鱼 (Ctenopharyngodon idellus) 8.63万尾、8.63 t，大鳞副泥鳅 (Paramisgurnus dabryanus) 0.68万尾、1.33 t，小口裂腹鱼 (Schizothorax microstomus) 0.07万尾、0.22 t。此次调查未发现曾出现记录的宁蒗裂腹鱼 (S. ninglangensis) 和厚唇裂腹鱼 (S. labrosus)。

Underwater acoustics in marine fisheries and fisheries research

From August 15 to 19, 2018, we assessed the spatial distribution and resources of fish in Lugu Lake, Yunnan Province for the first time by using lowrange elite-7 Ti echo detector. Zigzag route was used to detect the whole Lugu Lake, with a total voyage of 42.71 km. Based on the depth variation value, the lake was divided into a number of detection units for fish resources evaluation, and the spatial distribution map was drawn based on the density of each unit by inverse distance weighting (IDW). The results of hydroacoustic survey shows that the spatial distribution of fish in Lugu Lake was uneven. In the horizontal direction, most fish clusters were distributed in the coastal annular waters, among which the fish density in the waters near Xiaoyuba was the highest, while the fish density in the middle of the lake was the lowest; in the vertical direction, the fish distribution in the surface waters was relatively concentrated. In August 2018, the fish density in Lugu Lake was 0.153·(1 000 m³)⁻¹; the total number of fish was 243 900 and the total resource was 50.55 t (Carassius auratus: 211 700 ind., total mass of 17.36 t; Cyprinus carpio: 17 400 ind., total mass of 23.01 t; Ctenopharyngodon idellus: 86 300 ind., total mass of 8.63 t; Paramisgurnus dabryanus: 6 800 ind., total mass of 1.33 t; Schizothorax microstomus: 700 ind., total mass of 0.22 t). In this survey, there was no records of S. ninglangensis and S. labrosus which had been found in previous investigation.