The Norwegian Environmental Association ( NMF ) has for years considered that the shell sampling and reading of the shells, in order to find out whether the salmon that the fisherman has caught on land during river fishing, is not enough to classify the salmon as native wild salmon, or whether it is salmon with farming genes .
The reason why NMF believes that only reading the shells is not enough is that reading the shells can only reveal whether the salmon has been raised in a river or not. In this way, all mixtures of wild salmon and farmed salmon, and pure offspring of farmed salmon, are automatically classified as indigenous wild salmon, as these have also grown up in rivers.
See media reports here:
Require that all salmon caught in our rivers must be DNA tested
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Norwegian 
