ABSTRACT Fish odor induces predator avoidance behaviors in zooplankton, like vertical migration, by making zooplankton more responsive to light. Odor cues that alter behavior in marine crustacean zooplankton in the laboratory include sulfated glycosaminoglycans (sGAGs) derived from fish body mucus. Few studies quantify these cues in estuarine/marine environments or assess whether laboratory studies reflect natural scenarios. We collected fish and water samples weekly in Broadkill River, Delaware, USA. We used field-collected water in colorimetric assays to determine the concentration of sGAG-equivalent molecules and in behavioral assays with a zooplankton model, brine shrimp (Artemia spp.) nauplii, which only descend in response to downwelling light after fish odor exposure. Fish quantity was positively related to sGAG-equivalents and zooplankton photosensitivity, indicated by descent responses at lower light levels and across a broad intensity range. Our results support that fish odor concentrations used in previous laboratory assays are consistent with levels found in an estuary.

中文翻译：

---

河口鱼类、鱼类气味和浮游动物光行为的自然变化

摘要 鱼的气味通过使浮游动物对光更敏感，从而诱导浮游动物的捕食者回避行为，如垂直迁移。实验室中改变海洋甲壳类浮游动物行为的气味线索包括源自鱼体粘液的硫酸化糖胺聚糖 (sGAGs)。很少有研究在河口/海洋环境中量化这些线索或评估实验室研究是否反映了自然情景。我们每周在美国特拉华州布罗德基尔河采集鱼类和水样。我们在比色测定中使用现场收集的水来确定 sGAG 等效分子的浓度，并在使用浮游动物模型丰年虾（卤虫属）无节幼体的行为测定中使用，这些无节幼体仅在鱼气味暴露后响应向下流光而下降。鱼的数量与 sGAG 等价物和浮游动物光敏性呈正相关，这由较低光照水平和广泛强度范围内的下降反应表明。我们的结果支持以前实验室检测中使用的鱼气味浓度与河口中发现的水平一致。