Greater species variety shown than with hoop-net sampling
Tracing fish using eDNA
On a commission from the Dutch Directorate for Public Works and Water Management (Rijkswaterstaat), KWR is conducting environmental DNA (eDNA) research into fish in the Gelderland IJssel. 6 target species have been encountered, which is 2 more than the number found using traditional hoop nets, the method employed up until now. eDNA research is one of KWR’s new key focus areas.
eDNA research is a new manner of determining biodiversity levels in water. The monitoring of species variety is at the top of European and global agendas. The technique provides a new method to research whether the legal and regulatory provisions concerning surface water are being met. Monitoring programmes are, generally speaking, extensive and therefore expensive. Based on DNA techniques, one can build a method that offers a faster, cheaper and more precise alternative to regular sampling procedures. KWR is working on the cutting edge of the development and implementation of these methods. “We are happy that Rijkswaterstaat is one of the first parties to dare to apply eDNA methods,” says researcher Edwin Kardinaal. “At some point you just have to get started. Only then will you get the ball rolling so that the supply and demand dynamic can begin operating.”
eDNA is a faster, cheaper and more precise alternative to regular sampling procedures
Over the last decades, Rijkswaterstaat has employed the hoop-net sampling method as input for its knowledge of the fish target species in Dutch inland waterways. Among other things, the target species provide the basis for assessing measures in force and determining the nature of any new ones. “Because of the decline in professional hoop-net fishing, Rijkswaterstaat is looking for an alternative,” says Kardinaal. The ecological consultants Koeman en Bijkerk and KWR are jointly developing eDNA methods in combination with a sophisticated sampling strategy, which they use to study the extent to which these could provide the desired alternative. Water samples are analysed in the laboratory to determine the presence of fish DNA, which ends up in the water via faeces, skin cells or mucus, for instance. The method is a success. Kardinaal explains: “Based on approximately 2,400 DNA analyses, we have shown the presence of six target species: perch, roach, ide, bleak, bullhead and catfish. We use the PCR technique for the DNA analysis. The technique is based on the amplification of low concentrations of species-specific DNA, as present in the environment. One thereby renders the DNA observable and, using calibration lines, can quantify the original amounts.”
Macro fauna and other organisms
Besides the above research, KWR has been studying the broad application of eDNA techniques for a number of years. For example, large and small loaches can be effectively traced using eDNA techniques. These fish species are protected, but are hard to find because of their secluded lifestyle. The eDNA techniques are also used to map the presence of invasive exotic species, such as crayfish. It is important for water managers to know where these animals are present since, among other things, they can cause damage to the waterways’ banks. Also, in early 2014, RoyalHaskoningDHV, Naturalis Biodiversity Center, Koeman en Bijkerk, BaseClear and KWR begin a TKI project in which they are studying whether DNA barcode information can be used to develop alternatives to the existing inventory methods. To begin with, their focus is on 3 macro fauna groups: water bugs, water beetles and midges. Later in 2014, an eDNA tool will be added to the Watershare® Suite of tools.
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Manager Microbial Water Quality and Health and scientific researcher