Assessment of otolith chemistry for identifying source environment of fishes in the lower Illinois River, Illinois
Assessment of otolith chemistry for identifying source environment of fishes in the lower Illinois River, Illinois
复制标题
评估伊利诺伊州伊利诺伊州下游鱼类来源环境的耳石化学
作者：
J. M. Zeigler;G. Whitledge
了解鱼类在整个生命史中使用的栖息地对于河流鱼类种群和栖息地的管理和保护非常重要。耳石中天然存在的化学标记最近已被用来确定各种海洋和淡水环境中鱼类的出生起源和环境历史。然而，据我们所知，还没有研究检验该技术在美国大型洪泛区河流中的适用性。我们评估了耳石微化学和稳定同位素组成作为确定伊利诺伊河下游、其支流和洪泛区湖泊鱼类起源的工具。 2006 年夏季从 8 个地点采集了鱼类，2007 年春季从另外两个地点采集了鱼类。2006 年夏季和秋季以及 2007 年春季从这 10 个地点以及另外一个支流采集了水样。对耳石和水样进行了 δ18O 和一系列微量元素分析；还分析了耳石的 δ13C。支流、漫滩湖泊和伊利诺伊河具有独特的同位素和元素特征，主要是由漫滩湖泊、伊利诺伊河和支流之间 δ18O 和 δ13C 的差异驱动的。耳石反映了栖息地之间水化学的差异。水与耳石 δ18O 和 Sr:Ca 之间的关系在物种间没有显着差异，但水与耳石 Ba:Ca 之间的关系在物种间检测到一些差异。对耳石 δ18O 和 δ13C 进行留一折刀程序的线性判别函数分析表明，鱼类可以以 80-98% 的准确度分类回捕获环境（伊利诺伊河、支流或洪泛区湖泊）。耳石微化学和稳定同位素分析为确定伊利诺伊河鱼类的补充来源和环境历史提供了一种潜在有效的手段。使用耳石中天然存在的同位素标记重建个体鱼类环境历史的能力也可能有助于量化从洪泛区湖泊或支流迁徙的鱼类为伊利诺伊河提供的营养和能量补贴。
Knowledge of habitats used by fish throughout their life history is important for the management and conservation of riverine fish populations and habitats. Naturally occurring chemical markers in otoliths have recently been used to determine natal origins and environmental history of fishes in a variety of marine and freshwater environments. However, to our knowledge, no studies have examined the applicability of this technique in large floodplain rivers in the USA. We evaluated otolith microchemistry and stable isotopic composition as tools for determining origins of fishes in the lower Illinois River, its tributaries, and floodplain lakes. Fishes were collected from eight sites during summer 2006 and two additional sites in spring 2007. Water samples were obtained from these 10 sites plus one additional tributary during summer and fall 2006 and spring 2007. Otolith and water samples were analyzed for δ18O and a suite of trace elements; otoliths were also analyzed for δ13C. Tributaries, floodplain lakes, and the Illinois River possessed distinct isotopic and elemental signatures, principally driven by differences in δ18O and δ13C among floodplain lakes, the Illinois River, and tributary streams. Otoliths reflected the differences in water chemistry among habitats. Relationships between water and otolith δ18O and Sr:Ca were not significantly different among species, but some differences in relationships between water and otolith Ba:Ca among species were detected. Linear discriminant function analysis with a leave-one-out jackknife procedure on otolith δ18O and δ13C indicated that fish may be classified back to environment (Illinois River, tributary, or floodplain lake) of capture with 80–98% accuracy. Otolith microchemistry and stable isotope analyses provide a potentially effective means for determining recruitment sources and environmental history of fishes in the Illinois River. The ability to reconstruct environmental history of individual fish using naturally occurring isotopic markers in otoliths may also facilitate efforts to quantify nutrient and energy subsidies to the Illinois River provided by fishes that emigrate from floodplain lakes or tributaries.