Assessing the impacts of climate change on water resources of a West African trans-boundary river basin and its environmental consequences (Senegal River Basin)

Cheikh, Bécaye Gaye; Mor, Diaw; Malou, Raymond

doi:10.3724/sp.j.1226.2013.00140

Cited by 4 publications

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Prawns in our experiment were likely acclimated to ambient temperatures in our outdoor growing ponds but could not migrate to more favorable temperatures in waterways once placed in experimental cages. Summer water temperatures in the Senegal River Basin can reach 32°C (Sane, Ngansoumana, Arfi, Samb, & Noba, 2017), with air temperatures reaching 40°C (Cheikh, Moctar, & Raymond, 2013). Given that each degree Celsius rise in temperatures increases oxygen demand by increasing prawn metabolism (Manush, Pal, Chatterjee, Das, & Mukherjee, 2004; Xi-lin et al, 1999), water temperatures at release sites may have increased prawn mortality by raising oxygen demands.…”

Section: Discussionmentioning

confidence: 99%

Identifying low risk insecticides that can enhance food production without increasing mortality of biocontrol agents for human schistosomiasis

Haggerty

Delius

Jouanard

et al. 2021

Preprint

View full text Add to dashboard Cite

Synthetic chemicals, such as pesticides, have increased faster than other agents of global change have, yet their ecological impacts remain understudied. Additionally, agricultural expansion to address human population growth and food shortages is predicted to increase the use of pesticides, some of which have been linked to increases in infectious diseases of humans, such as schistosomiasis, which infects >250 million people worldwide. Previous work revealed that ecologically relevant concentrations of organophosphate and pyrethroid insecticides are highly toxic to crayfish. Whether these same insecticides are also highly toxic to Macrobrachium rosenbergii and M. vollenhovenii prawns, which are closely related to crayfish and are important predators on snails that transmit schistosomiasis in Asia and Africa, respectively, is unknown. We performed laboratory dose-response studies for M. rosenbergii using three pyrethroid (esfenvalerate, λ-cyhalothrin, and permethrin) and three organophosphate (chlorpyrifos, malathion, and terbufos) insecticides. Pyrethroid LC50 values were consistently several orders of magnitude lower than for organophosphate insecticides. Pyrethroids also had a greater likelihood of field runoff at levels lethal to prawns. To corroborate these findings in natural settings, we experimentally tracked survival of individually caged M. vollenhovenii at 31 waterways in West Africa that varied widely in their insecticide use. Consistent with laboratory results, pyrethroid insecticide use in these villages was positively associated with Macrobrachium mortality when controlling for village-level and prawn-level attributes, including levels of organophosphate applications. Villages with the most pyrethroid use had lower prawn survival, despite using on average 20% less total insecticides than villages with high prawn survival. Our findings suggest that pyrethroid insecticides widely used in sub-Saharan Africa have strong non-target effects on Macrobrachium spp. prawns, with possible implications for human schistosomiasis. Thus, regulations or incentives to avoid high-risk insecticides, especially near waterways, could have important human health implications in countries undergoing agricultural expansion in schistosomiasis-endemic regions.

show abstract