Here, I relate what the journalist said in his article “Les poissons sont aussi victimes des insecticides « tueurs d’abeilles »”. All quotes, originally in French, were translated by me.
A study by Japanese researchers led by Masumi Yamamuro published on October 31 by Science studies the effect of NNIs on fishing. (Yamamuro et al. 2019) The introduction of imidacloprid to the rice fields of Shimane in 1993 is said to have collapsed the capture of two important commercial species: Japanese eel and wakasagi.
Catches of wakasagi increased from 240 tonnes before 1993 to 22 tonnes in the following years. Those of eels fell from 42 tonnes to less than 11. The researchers would have followed the concentrations of imidacloprid over 20 years and followed the evolution of the abundance of small aquatic organisms. They observed that populations of aquatic arthropods collapsed in the same year as the 1993 introduction of imidacloprid.
This fall would have caused the fall of the eel and wakasabi populations, which feed on these organisms. This link was validated by the fact that another species feeding not on invertebrates, but on microalgae, was not affected during the period studied.
Foucart recalls studies conducted by Caspar Hallman (et al. 2014), which in 2014 would have shown an association “between the concentrations of imidacloprid in surface water throughout the Dutch territory with, on the one hand, the abundance of aquatic invertebrates (larvae insects, etc.) and on the other hand the rate of decline of exclusively or partially insectivorous passerines.” Concentrations of more than 20 µg / l were correlated with an average decline in populations of these birds of 3.5% per year, ie a reduction of half in two decades.