Beach seine gear in operation in Malawi’s Upper Shire River. Photo by F. Kapute.
Assessing the Impacts of Mosquito Net Fishing in Malawi
By Paola Bernazzani, Kate Minden and Michael Tillotson
Malaria is one of the major sources of morbidity and mortality in Malawi across all age groups. Reducing this burden is both a human and economic development need, recognized by the government of Malawi, USAID, and donors. Universal use of long-lasting insecticidal bednets (LLINs) is a foundation of Malawi’s National Malaria Strategic Plan.
LLINs are distributed broadly by USAID, the U.S. President’s Malaria Initiative (PMI), and other aid organizations and form a critical component of malaria prevention efforts globally. These nets also represent a low- or no-cost material source for communities, and new or aged nets are commonly repurposed for many unapproved uses. In Malawi, LLINs are incorporated extensively into the fishing industry, with pervasive use for catching and processing fish from Lake Malawi and other water bodies.
The misuse of LLINs for mosquito net fishing has received significant attention in Malawi and elsewhere. There is widespread concern that mosquito net fishing at sufficient intensity can result in over-abstraction of juvenile fish and damage to productive and sensitive shallows. Drying fish on bednets and intensive use of LLIN-covered fishtraps may pose additional risks to human health and freshwater ecosystems. USAID and PMI have previously invested in studies to understand the causes of mosquito net fishing, including in Malawi. However, assessments of the nature, scale, and impacts of mosquito net fishing in Malawi (and other countries) have been scarce.
Application of Novel Fisheries Assessment Tools to Overcome Unexpected Change in On-the-ground Conditions for Malawi Bednet Environmental Assessment
To support an environmental assessment (EA) of continued LLIN distribution in Malawi, USAID tasked ICF with quantifying ecological impacts of mosquito net fishing in Lake Malawi and other sensitive water bodies. A scoping study reported widespread use of LLINs in Lake Malawi’s largest fishery, and ICF planned a follow-up field effort to sample catches and inform a quantitative fisheries model. However, during the second field effort substantial change had occurred in mosquito net fishing patterns, and significantly reduced LLINs were observed in the target fishery.
ICF rapidly pivoted, evaluating alternative analytical techniques to overcome conflicting information and severe data limitations, while providing USAID with the information required for the EA. A qualitative risk assessment approach, Productivity-Susceptibility Analysis (PSA), was ultimately identified as a suitable tool for qualitatively evaluating fisheries and management actions in the Lake. A recent extension of the approach, developed by scientists from the National Marine Fisheries Service that more explicitly characterizes uncertainty was ultimately implemented. The PSA was applied to multiple Lake Malawi fish populations, and the results provided important insight into the relative contribution of MNF to the vulnerability of this critical aquatic ecosystem.
Design and Facilitation of in-country Experiments to Evaluate Human Health and Environmental Risks from Long-Lasting Insecticide Treated Nets
After a preliminary analysis indicated the potential for human health risks to result from the common practice of lining fish drying racks with LLINs distributed by USAID and other organizations, ICF designed and facilitated implementation of an experimental study to further evaluate risk. ICF developed a robust experimental design for measuring pesticide residues in fish dried on LLINs and worked with USAID to identify and obtain examples of net types that have been recently distributed or are planned for distribution in Malawi in the near future.
ICF partnered with an in-country fisheries biologist to implement the experimental fish drying and then facilitated transport of dried fish samples to the United States for analysis in a certified laboratory. In contrast to the preliminary analysis, the experimental study indicated minimal health risk from this widespread fish processing practice.
ICF also worked with a chemicals teaming partner to analyze the risks of pesticide leaching into water bodies and potential uptake by aquatic organisms. This desktop analysis revealed that pesticide leaching from LLINs poses low risk to aquatic species with the exception of transference to benthic microorganisms from sedentary fish traps in shallow lakes.
Both results allow the prioritization of LLIN misuse mitigation efforts towards ecologically damaging uses in fishing gears.
Near- and Long-Term Benefits of the Assessment Process
The findings from the various components of the EA process, including the PSA and the experimental studies, have helped fill critical gaps in knowledge surrounding the extent and impacts of LLIN misuse in Lake Malawi. While the illegal use of LLINs for fishing in the region, as well as its high-level causes, was known prior to this project, the effects of LLIN use had not previously been examined, including the extent to which LLIN misuse for fishing is impacting or will continue to impact Malawi’s fisheries, human health, and ecosystems. By comprehensively assessing the extent and current and projected impacts of MNF in Malawi, this EA has many long-term benefits, including influencing real reductions in the use of MNF for fishing in Malawi, influencing programming designed to reduce poverty in communities surrounding Lake Malawi, promoting more resilient fisheries, and protecting and improving biodiversity in the region.
Meet the authors
Paola Bernazzani, International Environmental Planning Director
Paola Bernazzani is an international environmental planning director and the activity manager and biodiversity expert for the USAID-funded Routine Distribution of LLINs in Malawi Environmental Assessment.
Michael Tillotson, Senior Biologist
Michael Tillotson is a senior biologist at ICF.