【摘要】 有关杂食性鱼类对沉水植物的影响研究目前多集中在个体较大的种类（如鲤、鲫），对小型个体研究较少，小型杂食性鱼类主要以沉水植物为食，其对不同沉水植物的选择性摄食目前尚不清楚。通过受控实验研究了大鳍鱊(Acheilognathus macropterus)对4种沉水植物轮叶黑藻（Hydrilla verticillata）、密刺苦草（Vallisneria denseserrulata）、金鱼藻（Ceratophyllum demersum）和穗花狐尾藻（Myriophyllum spicatum）的选择性摄食，分析大鳍鱊对这些沉水植物生长的影响。结果显示（：1）大鳍鱊显著增加了水体营养盐浓度，降低了水体pH值（；2）大鳍鱊对穗花狐尾藻和金鱼藻具有较强的选择性，2种植物占鱼类肠含物的比例分别为75%和17%，大鳍鱊对密刺苦草的牧食较少(8%)，内含物中未出现轮叶黑藻（；3）大鳍鱊显著抑制了穗花狐尾藻和金鱼藻的相对生长率(RGR)，而对轮叶黑藻和密刺苦草的RGR有促进作用。研究表明，大鳍鱊对不同沉水植物有明显的摄食选择性，其摄食活动可显著降低沉水植物的生物量。大鳍鱊或者其他小型杂食性鱼类(如麦穗鱼和鲹等)可能会通过选择性摄食沉水植物的途径影响其群落结构和生物量，严重时可能会影响湖泊生态系统结构的稳定性。在湖泊管理与生态修复中,需要关注此类小型杂食性鱼类的种群规模，将其控制在较低生物量水平。更多还原

【Abstract】 Studies on the effects of omnivorous fish on submerged macrophytes are mostly on large fish species such as Cyprinus carpio and Carassius carassius. However, submerged macrophytes are the primary food source of small omnivorous fish species, their feeding preference for different submerged macrophytes is not yet clear. In this investigation, Acheilognathus macropterus, a typical small fish species widely distributed in China, was selected for study. We conducted a controlled experiment to study the feeding preference of A. macropterus among four submerged macrophytes(Vallisneria denseserrulata,Hydrilla verticillata, Ceratophyllum demersum and Myriophyllum spicatum), and analyzed the effect of A. macropterus feeding on the growth of each macrophyte species. The objective was to provide reference for ecological restoration and management of shallow lakes. Two macrophyte groups were set for the experiment, one with no fish(control group) and the second with fish(treatment group). A single plant of each macrophyte species, with the same biomass was placed in each of two aquaria, and one A. macropterus of body length(12.2±0.3) cm and body weight(18.9±1.3) g was added to the treatment aquarium. Before and after the 11 day test, physicochemical parameters of the water were measured, and the pH and temperature of the water were measured each day. The gut content of A. macropterus was observed under the microscope after the test. Results show that(1) nutrient concentrations in the fish treatment were significantly higher than that in the control group and the pH was lower.(2) Gut content analysis showed that A. macropterus preferred M. spicatum and C. demersum, with the two species accounting for 75% and17% of the gut contents, respectively. The fish fed less on V. denseserrulata(8%) and H. verticillata was not observed in the gut.(3) At the end of the experiment, the relative growth rate(RGR) of both M. spicatum and C. demersum were significantly reduced by A. macropterus, whereas the RGR of H. verticillata and V. denseserrulata were higher than in the control group, although the difference was not significant.To summarize, A. macropterus displayed an obvious feeding preference for M. spicatum and C. demersum and significantly reduced their RGRs. Furthermore, A. macropterus significantly increased the nutrient concentration in the aquarium and reduced the total macrophyte biomass, compared with the control.Therefore, A. macropterus and other small omnivorous fish species(e. g. Pseudorasbora parva and Hemiculter leucisculus) may reduce the biomass of submerged macrophytes and change the community structure via selective grazing, negatively affecting the water quality and stability of lake ecosystems.When plans for lake management and ecological restoration are being developed, the effect of small omnivorous fish is of concern and their biomass in the community should be controlled to a low level.更多还原