Johnston Thomas A, Leggett William C, Bodaly Richard A, Swanson Heidi K
Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada.
Environ Toxicol Chem. 2003 Sep;22(9):2057-62. doi: 10.1897/02-265.
We evaluated the prediction that mercury concentrations of predatory fishes in boreal lakes would rise following the invasion of an exotic forage fish species (rainbow smelt, Osmerus mordax) that was believed to feed at a higher trophic position than native forage fishes. We compared temporal trends (postinvasion minus preinvasion values) in fish mercury bioaccumulation between lakes experiencing recent smelt invasions and reference lakes of central Canada. Piscivore mercury concentrations in this region have remained stable or declined during approximately the last 20 years. These trends were not strongly influenced by the smelt invasion, despite the fact that smelt were a major prey item for all piscivore species examined. The effect of smelt invasion on mercury bioaccumulation in the predator species reflected the importance of smelt in their respective diets (lake trout, Salvelinus namaycush > walleye, Stizostedion vitreum > northern pike, Esox lucius). However, these effects were not statistically significant for any piscivore species. The impact of rainbow smelt invasion on mercury bioaccumulation in native piscivores of this region has been much less than previous food-web studies have predicted.
在北方湖泊中，随着一种外来饵料鱼物种（虹鳟，Osmerus mordax）的入侵，掠食性鱼类的汞浓度将会上升，据信该外来物种所处的营养级高于本地饵料鱼。我们比较了近期经历过虹鳟入侵的湖泊以及加拿大中部的参照湖泊中鱼类汞生物累积的时间趋势（入侵后值减去入侵前值）。在大约过去20年里，该地区肉食性鱼类的汞浓度一直保持稳定或有所下降。尽管虹鳟是所有被研究的肉食性鱼类的主要猎物，但这些趋势并未受到虹鳟入侵的强烈影响。虹鳟入侵对捕食者物种汞生物累积的影响反映了虹鳟在其各自食谱中的重要性（湖鳟，Salvelinus namaycush > 大眼狮鲈，Stizostedion vitreum > 白斑狗鱼，Esox lucius）。然而，对于任何肉食性鱼类物种而言，这些影响在统计学上并不显著。虹鳟入侵对该地区本地肉食性鱼类汞生物累积的影响远小于此前食物网研究所预测的程度。
