南海北部海域小型非经济鱼类资源声学评估

根据2015年7—8月(夏季)和2015年12月—2016年1月(冬季)对南海北部陆坡海域(111°00′E~120°00′E，18°00′N~22°00′N)的中层拖网调查，对该海域的夏季和冬季的渔业资源种类组成、优势种和生物多样性特征进行了初步研究。结果表明，南海北部陆坡海域夏、冬季共出现渔业生物273种，其中鱼类205种，甲壳类50种，头足类18种。相对性重要指数(IRI)分析表明，尾明角灯鱼(Ceratoseopelus warmingii)和典型刺虾(Oplphorus typus)为该海域的优势种类(IRI≥500)；主要种为条带眶灯鱼(Diaphus brachycephalus)、菲氏眶灯鱼(D.Phillipis)、短距眶灯鱼(D.mollis)、马来眶灯鱼(D.malayanus)、长鳍虹灯鱼(Bolinichthys longipes)和天纽珍灯鱼(Lampanyctus tenuiformis) (100≤IRI<500)。夏季和冬季的Shannon-Wiener多样性指数(H′)平均值分别为4.34和5.26，Margalef丰富度指数(D)平均值分别为3.41和4.03，Peilou均匀度指数(J′)平均值分别为0.70和0.79，冬季各多样性特征指数均大于夏季。多样性特征指数与水深呈显著正相关，与水温呈负相关，说明该海域群落多样性分布存在一定的环境梯度特征。

Nitrogen versus phosphorus enrichment of brackish waters: responses of the submersed plant Potamogeton perfoliatus and its associated algal community

Based on the fisheries resources data collected from two mid-trawl surveys from the northern slope of the South China Sea (111°00′E−120°00′E, 18°00′N−22°00′N) during August, 2015 and December 2015−January 2016, we investigated the community structure, dominant species and diversity of fishery resources in that area. A total of 273 fishery species were recorded, including 205 fishes, 50 crustaceans and 18 cephalopods. The index of relative importance (IRI) analysis shows that Ceratoseopelus warmingii and Oplphorus typus were the dominant species (IRI≥500). Diaphus brachycephalus, D. Phillipis, D. mollis, D. malayanus, Bolinichthys longipes and Lampanyctus tenuiformis were identified as the main species (100≤IRI < 500). The average Shannon-Wiener diversity index (H′), Pielou evenness index (J′) value and Margalef richness index (D) of fishery resources were 4.34, 0.70 and 3.41 in summer, respectively, and were 5.26, 0.79 and 4.03 in winter, respectively. Generally, the diversity index of winter was higher than that of summer. The diversity index was positively correlated with seawater depth, but negatively correlated with seawater temperature, indicating a certain environmental gradient in distribution of community diversity.