Environmental DNA (eDNA) promises to ease noninvasive quantification of fish biomass or abundance, but its integration within conservation and fisheries management is currently limited by a lack of understanding of the influence of eDNA collection method and environmental conditions on eDNA concentrations in water samples. Water temperature is known to influence the metabolism of fish and consequently could strongly affect eDNA release rate. As water temperature varies in temperate regions (both seasonally and geographically), the unknown effect of water temperature on eDNA concentrations poses practical limitations on quantifying fish populations using eDNA from water samples. This study aimed to clarify how water temperature and the eDNA capture method alter the relationships between eDNA concentration and fish abundance/biomass. Water samples (1 L) were collected from 30 aquaria including triplicate of 0, 5, 10, 15 and 20 Brook Charr specimens at two different temperatures (7 °C and 14 °C). Water samples were filtered with five different types of filters. The eDNA concentration obtained by quantitative PCR (qPCR) varied significantly with fish abundance and biomass and types of filters (mixed-design ANOVA, P < 0.001). Results also show that fish released more eDNA in warm water than in cold water and that eDNA concentration better reflects fish abundance/biomass at high temperature. From a technical standpoint, higher levels of eDNA were captured with glass fibre (GF) filters than with mixed cellulose ester (MCE) filters and support the importance of adequate filters to quantify fish abundance based on the eDNA method. This study supports the importance of including water temperature in fish abundance/biomass prediction models based on eDNA.

中文翻译：

---

从eDNA浓度估算鱼类的丰度和生物量：捕获方法和环境条件之间的差异。

环境DNA（eDNA）有望简化鱼类生物量或丰富度的非侵入式定量，但是由于缺乏对eDNA采集方法和环境条件对水样中eDNA浓度的影响的了解，目前其在保护和渔业管理中的整合受到限制。众所周知，水温会影响鱼类的新陈代谢，因此可能会严重影响eDNA的释放速率。由于温带地区（季节性和地理上）的水温变化，水温对eDNA浓度的未知影响对使用水样品中的eDNA定量鱼类种群提出了实际限制。这项研究旨在阐明水温和eDNA捕获方法如何改变eDNA浓度与鱼类丰度/生物量之间的关系。在两个不同的温度（7°C和14°C）下，从30个水族馆收集了水样（1 L），其中包括0、5、10、15和20个Brook Charr标本的一式三份。水样用五种不同类型的过滤器过滤。通过定量PCR（qPCR）获得的eDNA浓度随鱼类丰度，生物量和过滤器类型的不同而显着不同（混合设计ANOVA，P <0.001）。结果还表明，鱼类在温水中释放的eDNA比在冷水中释放的eDNA多，并且eDNA浓度更好地反映了高温下鱼的丰度/生物量。从技术角度来看，玻璃纤维（GF）过滤器比混合纤维素酯（MCE）过滤器捕获的eDNA含量更高，并支持使用适当的过滤器来量化基于eDNA方法的鱼类丰度的重要性。