Accurate stock assessment is essential but difficult as it relies on fisheries-depended and fisheries-independent data. Independent data is acquired by trawling surveys, which are habitat invasive, selective and labour intensive. Environmental DNA (eDNA) is a promising uprising technique that could provide a more sensitive and less invasive stock assessment than current techniques. Many species-specific factors influence shedding of eDNA that are currently insufficiently researched. In this study, the influence of biomass, body size, time, number of individuals and spatial patterns on the shedding rate of European plaice (Pleuronectes platessa) were researched. Biomass was found to have the best correlation with number of eDNA copies/µl, time and number of individuals made the result more accurate in an experimental setting. No definitive conclusion came out of the analysis of field samples for the small spatial patterns, likely due to low number of plaice caught and low number of replicas. No correlation was found between eDNA concentration and the number of plaice caught by trawling, although a positive trend was observed. This illustrates that more research needs to be done in the natural marine environment before eDNA can be used for stock assessment.
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