Fluid-preserved fishes are one solution for assessing historical change in fish trophic level

There are few resources available for assessing historical change in fish trophic dynamics, but specimens held in natural history collections could serve as this resource. In contemporary trophic ecology studies, trophic and source information can be obtained from compound-specific stable nitrogen isotope analysis (CSIA-AA-N). Can this method yield reliable trophic information from chemically-altered fish specimens held in natural history collections? We tested whether CSIA-AA-N can be used on fluid-preserved specimens by experimentally subjecting specimens to the most common natural history collections preservation protocol, and determining the effects of preservation on trophic level estimates and whether these effects stabilize over time.

We subjected whole Sebastes ruberrimus and Clupea pallasii to formalin fixation and 70% ethanol preservation. We extracted tissue samples from each fish pre-fixation, after each chemical change, and then in doubling time for 32–64 days once place...

评估鱼类营养动力学历史变化的可用资源较少，但自然历史馆藏中的标本可作为此类资源。在当代营养生态学研究中，营养和来源信息可通过化合物特异性稳定氮同位素分析（CSIA-AA-N）获得。这种方法能否从自然历史馆藏中化学处理过的鱼类标本中获取可靠的营养信息？我们通过实验将标本置于最常见的自然历史馆藏保存方案中，测试CSIA-AA-N是否可用于流体保存标本，并确定保存对营养级估计的影响以及这些影响是否随时间稳定。

我们将完整的红大岩鱼（Sebastes ruberrimus）和太平洋鲱（Clupea pallasii）进行福尔马林固定和70%乙醇保存处理。我们在固定前、每次化学处理后，以及在放置后以倍增时间（32–64天）提取每条鱼的组织样本...