Quantifying spawning biomass of commercially relevant fish species is important to generate fishing quotas. This will mostly rely on the annual or daily production of fish eggs. However, these have to be identified precisely to species level to obtain a reliable estimate of offspring production of the different species. Because morphological identification can be very difficult, recent developments are heading towards application of molecular tools. Methods such as COI barcoding have long handling times and cause high costs for single specimen identifications. In order to test MALDI-TOF MS, a rapid and cost-effective alternative for species identification, we identified fish eggs using COI barcoding and used the same specimens to set up a MALDI-TOF MS reference library. This library, constructed from two different MALDI-TOF MS instruments, was then used to identify unknown eggs from a different sampling occasion. By using a line of evidence from hierarchical clustering and different supervised identification approaches we obtained concordant species identifications for 97.5% of the unknown fish eggs, proving MALDI-TOF MS a good tool for rapid species level identification of fish eggs. At the same time we point out the necessity of adjusting identification scores of supervised methods for identification to optimize identification success.

Significance

Fish products are commercially highly important and many societies rely on them as a major food resource. Over many decades stocks of various relevant fish species have been reduced due to unregulated overfishing. Nowadays, to avoid overfishing and threatening of important fish species, fish stocks are regularly monitored. One component of this monitoring is the monitoring of spawning stock sizes. Whereas this is highly dependent on correct species identification of fish eggs, morphological identification is difficult because of lack of morphological features.

中文翻译：

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通过蛋白质组指纹图谱使用MALDI-TOF MS快速鉴定鱼卵的种类

量化与商业相关的鱼类的产卵生物量对于产生捕捞配额很重要。这将主要取决于鱼卵的年产量或日产量。但是，必须准确地在物种水平上识别这些物种，以获得对不同物种后代产量的可靠估计。由于形态鉴定可能非常困难，因此最近的发展趋势是分子工具的应用。诸如COI条形码之类的方法需要较长的处理时间，并且会导致单样本鉴定的高昂成本。为了测试MALDI-TOF MS，这是一种快速，经济高效的物种识别方法，我们使用COI条形码识别了鱼卵，并使用相同的标本建立了MALDI-TOF MS参考库。该库由两种不同的MALDI-TOF MS仪器构建而成，然后被用于识别来自不同采样场合的未知卵。通过使用来自层次聚类和不同监督识别方法的证据，我们获得了97.5％未知鱼卵的一致物种识别，证明MALDI-TOF MS是快速鉴定鱼卵的良好工具。同时，我们指出有必要调整监督方法的识别分数以优化识别成功率。

意义

鱼产品在商业上非常重要，许多社会都将鱼作为主要食品资源。几十年来，由于过度捕捞，各种相关鱼类的种群减少了。如今，为避免过度捕捞和威胁重要鱼类，定期监测鱼类种群。监视的一个组成部分是监视产卵大小。尽管这在很大程度上取决于鱼卵的正确种类识别，但由于缺乏形态特征，因此很难进行形态识别。