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通过2003-2004年对太湖鱼类组成、优势鱼类鲚鱼的年龄结构及食物组成分析,结合鱼类渔获量统计和环境检测资料,研究了太湖鱼类渔获量、组成比例和优势鱼类湖鲚种群年龄结构的变化规律、机制以及相应变化对环境产生的下行效应。结果表明,太湖鱼类总渔获量已从1952年的4 060.7 t上升到2002年的30 516.5 t;鲚鱼已成为绝对优势种,从1952年的640.5 t,占15.8%,上升到2002年的19 571 t、占64.1%;鲚鱼种群年龄组成的低龄化趋势明显,种群中0+个体占(99.04±2.21)%(2003年)、(99.08±0.80)%(2004年);而0+鲚鱼主要以浮游动物为食,其中枝角类占食物总个数的(89.77±13.69)%;鲤鲫鱼1952-1998年期间相对稳定在(1 010.1±367.2)t,占总量的(8.89%±5.33)%,1999年达到2 547.4 t,占11.7%,2000-2002年达到(3 500~3 700)t,占总量的11.8%~14.7%,已成为太湖的主要鱼类之一;太湖的主要肉食性鱼类鮊鱼由最高年份(1987年)的1 090.8 t、占鱼类总量7.7%降至近8年(1995-2002年)的100~150 t、仅占0.4%~0.5%。分析认为:太湖鱼类总渔获量升高主要是鲚鱼的快速增加所引起;而鲚鱼快速增加的原因是富营养化引起的浮游生物数量快速增加及对其有抑制作用的鮊鱼数量不断减少所导致。鲚鱼数量升高又消耗了大量浮游动物,这可能成为太湖浮游植物失去抑制从而暴发的主要生物因素之一。
Based on the analysis of the age composition and food composition of fish species in Taihu Lake and the dominant species of fish from 2003 to 2004 and the fish catch statistics and environmental testing data, The changing regularity and mechanism of the age structure of the lakes and poplars, as well as the downward effect of the corresponding changes on the environment. The results showed that the total catch of fish in Taihu Lake increased from 4060.7 t in 1952 to 30 516.5 t in 2002. The pomfret became the dominant species, rising from 640.5 t in 1952 to 15.8% in 2002 Of the total population was 19 571 t, accounting for 64.1%. The age distribution of the catfish was significantly younger than that of the control group (0% of the individuals), (99.04 ± 2.21%) in 2003 and (99.08 ± 0.80%) in 2004 + Tuna mainly fed on zooplankton, in which the number of branches accounted for (89.77 ± 13.69)% of the total number of food; Carp crucian carp remained relatively stable at (1 010.1 ± 367.2) t from 1952 to 1998, accounting for ( 8 89% ± 5 33%), reached 2 547.4 t in 1999, accounting for 11.7% and reached 3 500-3 700 t in 2000-2002, accounting for 11.8% -14.7% of the total. It has become the major fish species in Taihu Lake The major carnivorous fish catfish in Taihu Lake dropped from 1 090.8 t in the highest year (1987) to 100 to 150 t in the recent 8 years (1995-2002), accounting for only 0.4% of the total fish stocks, from 7.7% ~ 0.5%. The analysis shows that the total catches of Taihu Lake are mainly caused by the rapid increase of catfish, while the rapid increase of catfish is due to the rapid increase of the number of plankton caused by eutrophication and the amount of catfish inhibited by them Continued to reduce the result. The increase of the number of anchovy and the consumption of a large number of zooplankton may be one of the main biological factors that lead to the outbreak of the phytoplankton in the Taihu Lake.