ENVIRONMENTAL-EFFECTS OF INTRODUCING WHITEFISH, COREGONUS-LAVARETUS (L), IN LAKE RING
ENVIRONMENTAL-EFFECTS OF INTRODUCING WHITEFISH, COREGONUS-LAVARETUS (L), IN LAKE RING
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DOI：
10.1007/bf00026701
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发表时间：
1994-02-25
期刊：
影响因子：
2.6
通讯作者：
MORTENSEN, E
中科院分区：
文献类型：
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作者：
BERG, S;JEPPESEN, E;MORTENSEN, E
白鲑（Coregonus lavaretus（L.））在丹麦的一个小型富营养化湖泊Lake Ring（22.5公顷，平均深度2.9米）中研究了富营养化湖泊的营养结构，其中天然鱼类区系以梭子鱼（Esox lucius L.）为主，河鲈（Perca fluviatilis L.），和鳗鱼（Anguilla anguilla（L.）），红拟鲤（Rutilus rutilus（L.））和江鳕（Lota lota（L.））是这里唯一的鱼类1989年10月至1990年7月，共放养了10 993 0 +白鱼，并在1989-91年期间研究了鱼类，浮游动物和底栖无脊椎动物群落的结构。胃内容物分析表明，白鲑主要吃水蚤和桡足类在1990-91，桡足类的比例随着鱼的大小和水蚤的整体最重要的食物来源的增加而减少。湖泊中水蚤密度由1989年的72个/l下降到1991年的9个/l，大型蚤和大型蚤也随之减少。蚤类几乎消失，剑水蚤桡足类的密度从72增加到101 ind. l-1，可能是由于食物条件的改善，而哲水蚤桡足类的密度几乎没有变化。结果，叶绿素a增加19至47杯L-1和Secchi深度从2.4米下降到1.7米，尽管没有变化，总P和总N（0.6毫克P L-1和1.3毫克N L-1，分别）。底栖无脊椎动物也发生了变化; Chaoborus、寡毛类和摇蚊都减少了，而Pisidium增加了。因此，在富营养化湖泊中放养白鲑可能会延缓其恢复，甚至导致富营养化加剧。
The impact of whitefish (Coregonus lavaretus (L.)) on the trophic structure of eutrophic lakes was studied in Lake Ring, a small eutrophic Danish lake (22.5 ha, mean depth 2.9 m) in which the natural fish fauna is dominated by pike (Esox lucius L.), perch (Perca fluviatilis L.), and eel (Anguilla anguilla (L.)), roach (Rutilus rutilus (L.)) and burbot (Lota lota (L.)) being the only other fish species present. A total of 10 993 0 + whitefish were stocked in the lake from October 1989 to July 1990 and the structure of the fish, zooplankton and benthic invertebrate communities studied during the period 1989-91. Stomach contents analysis revealed that the whitefish mainly ate Daphnia and copepods in 1990-91, the proportion of copepods decreasing with increasing size of the fish and Daphnia being the overall most important food source. The density of Daphnia in the lake decreased from 72 ind. l-1 in 1989 to 9 ind. l-1 in 199 1; concomitantly the large species Daphnia magna and D. pulex almost disappeared and the density of cyclopoid copepods increased from 72 to 101 ind. l-1, presumably because of improved food conditions, while that of calanoid copepods remained virtually unchanged. As a result chl-a increased from 19 to 47 mug l-1 and Secchi depth decreased from 2.4 m to 1.7 m, despite there being no change in total P and total N (0.6 mg P l-1 and 1.3 mg N l-1, respectively). Changes were also observed in the benthic invertebrates; Chaoborus, oligochaetes, and chironomids all decreased, whereas Pisidium increased. It is concluded that the stocking of whitefish in eutrophic lakes for commercial purposes may delay their recovery, or even lead to enhanced eutrophication.