Toxicological impacts of paddy field pesticides on red claw crayfish (Cherax quadricarinatus) and implications for integrated rice-crayfish farming

The integrated "rice-aquaculture" farming system is increasingly promoted in China as a sustainable agricultural model offering "dual benefits of grain and aquaculture". However, the safety of pesticides to co-cultured aquatic species, such as the red claw crayfish ( Cherax quadricarinatus ), requires thorough investigation. This study assessed the acute and chronic toxicological effects of six widely used chemical pesticides in paddy fields—abamectin, trifloxystrobin, triflumezopyrim, glufosinate-ammonium, zinc thiazole, and pretilachlor—on C. quadricarinatus under laboratory conditions. Acute toxicity tests revealed that abamectin and trifloxystrobin were highly toxic to C. quadricarinatus . Pretilachlor exhibited moderate toxicity. In contrast, triflumezopyrim, glufosinate-ammonium, and zinc thiazole demonstrated low acute toxicity. Subsequent chronic toxicity assessments (7-day exposure followed by a 14-day recovery) indicated that sub-lethal concentrations of triflumezopyrim, glufosinate-ammonium, and zinc thiazole induced neurotoxicity in C. quadricarinatus . Additionally, triflumezopyrim exposure led to oxidative stress, as evidenced by altered antioxidant enzyme activities and increased lipid peroxidation and DNA damage. Most notably, these sub-lethal effects-including significant changes in growth parameters (SGR, HSI), neurotoxicity (AChE inhibition), oxidative stress (SOD, CAT, MDA), and genotoxicity (8-OHdG) were largely reversible, consistently returning to control levels after a 14-day recovery in clean water. This demonstrated resilience provides a strong scientific basis for the periodic and safe application of these low-toxicity agents in integrated rice-crayfish system, while the highly toxic abamectin, trifloxystrobin, and moderate toxic pretilachlor pose significant risks and their use should be limited. This research provides a scientific basis for pesticide selection to support the sustainable development of integrated rice-red claw crayfish farming systems, contributing to the protection of aquatic ecosystems while ensuring the economic benefits of agricultural production. • Toxicities of six widely used chemical pesticides on Cherax quadricarinatus were assessed under laboratory conditions. • Triflumezopyrim, glufosinate-ammonium, and zinc thiazole show relative safety for rice-crayfish systems. • Abamectin, trifloxystrobin, and pretilachlor pose significant risks and their use should be limited in rice-crayfish systems.