Great news – herring were back in Wester Ross!
In spring this year, a feasibility study was conducted by WOSHH, involving shore-based environmental (e)DNA sampling, over a 6-week period, to find out if the method can detect the presence of herring in nearshore waters, at 3 different locations off Wester Ross. Environmental DNA (eDNA) is the DNA, shed by an organism (e.g., scales, excrement, etc.) or whole microorganisms, present in the environment. eDNA from water samples can be extracted, sequenced and linked back to species that were in the area. This makes it a potentially powerful, non-invasive tool to detect elusive spawning herring shoals through shore-based sampling.
The eDNA sampling was performed by members of local communities. Parallel to sampling eDNA near Gairloch, Peter Cunningham (Wester Ross Fisheries Trust) also collected marine plankton samples whilst kayaking 500m off the shore and found herring larvae (see report here)! Colleagues at Marine Scotland Science and SAMS confirmed that it was in fact herring. The larvae were roughly 3 to 4 weeks old, evidencing spawning by herring had happened somewhere nearby in March.
Knowing for sure that herring were present while collecting water samples taken near-shore will help evaluate if eDNA analysis is a reliable method to detect herring spawning events along the Scottish west coast. We are supported by the environmental tech company NatureMetrics and will provide a further update on the results when they become available