Neonicotinoids disrupt aquatic food webs and decrease fishery yields.

Area of Science:

• Environmental Science
• Ecotoxicology
• Aquatic Ecology

Background:

• Invertebrate declines are a significant ecological concern in terrestrial ecosystems, with pesticide use frequently implicated.
• Aquatic ecosystems face threats from highly toxic and persistent neonicotinoid insecticides.

Purpose of the Study:

• To investigate the impact of neonicotinoid insecticides on aquatic ecosystems and food web dynamics.
• To assess the cascading effects of pesticide contamination on higher trophic levels.

Main Methods:

• Analysis of zooplankton biomass, water quality data, and annual fishery yields (eel and smelt).
• Correlation analysis between neonicotinoid application in watersheds and observed ecological changes.
• Case study in Lake Shinji, Shimane Prefecture, Japan.

Main Results:

• Neonicotinoid application since 1993 correlated with an 83% decrease in spring zooplankton biomass.
• Smelt harvest in Lake Shinji collapsed from 240 to 22 tons following neonicotinoid introduction.
• Disruption of aquatic food web structure and dynamics affecting higher-level consumers.

Conclusions:

• Neonicotinoid insecticides pose a significant threat to aquatic ecosystems due to their toxicity and persistence.
• Pesticide-induced food web alterations can lead to severe declines in commercially important fisheries.
• The findings highlight the urgent need to address the global use of neonicotinoids to protect aquatic biodiversity and resources.