A comparison between benthic gillnet and bottom trawl for assessing fish assemblages in a shallow eutrophic lake near the Changjiang River estuary

作者：Li Yalei; Liu Qigen; Chen Liping; Zhao Liangjie; Wu Hao; Chen Liqiao; Hu Zhongjun^*

来源：Journal of Oceanology and Limnology, 2018, 36(2): 572-586.

DOI：10.1007/s00343-018-6219-5

• fishing gear
• expected species richness
• size structure
• catch per unit effort
• temperature

Two fishing methods including gillnetting and trawling to estimate attributes of fish assemblage were compared in Dianshan Lake from August 2009 to July 2010. Species composition differed significantly between the gears, with four significant contributors in gillnet catches and one in trawl catches. Trawling collected more proportions of benthic species by number and biomass than gillnetting. Size distribution was significantly influenced by fishing technique; gillnetting captured relatively less small-sized fishes and trawling captured less large-sized individuals. Trawling produced species richness closer to the one expected than gillnetting. On the whole, trawl catch was a quadratic polynomial function of gillnet catch and a significantly negative correlation was found between them, both of which varied as different polynomial functions of temperature. However, trawl and gillnet catches were significantly correlated only in one of five month groups. It is concluded that single-gear-based surveys can be misleading in assessments of attributes of fish assemblages, bottom trawling is a more effective gear for assessing fish diversity than benthic gillnetting, and using gillnet catches as an indicator of fish density depends on fishing season in the lake.

• 出版日期2018-3
• 单位环境保护部南京环境科学研究所; 上海海洋大学; 华东师范大学