Landscape-scale concordance between local ecological knowledge for tropical wild species and remote sensing of land cover.

Monitoring the status of species is crucial for biodiversity conservation and sustainable resource management in tropical forests, but conventional in situ monitoring methods are impractical over large scales. Scientists have resorted to two potentially complementary approaches: local ecological knowledge (LEK) and remote sensing. To gauge the potential of combining LEK and remote sensing for assessing species status at landscape scales, a large-scale assessment of the reliability of both measures is critical but hampered by the lack of ground-level data. We conducted a landscape-scale assessment of LEK and remote sensing, using a survey of over 900 communities (a near census in our study area) and nearly 4,000 households in 235 randomly selected communities in the Peruvian Amazon-the largest LEK survey as yet undertaken in tropical forests. The survey collected LEK data on the presence of 20 indicator species from both community leaders/elders and randomly sampled households. We assessed LEK and remotely sensed land cover-forest cover and nonmain channel open water-as proxies for species habitat, across species (game, fish, and timber), over time (current and historical), and by indigeneity (Indigenous peoples and mestizos). Overall, LEK and remotely sensed land cover corroborate each other well. Concordance is highest for the current status of game species reported by sampled households, as is the concordance of historical LEK from Indigenous community leaders/elders. The results point to the promise of combining LEK and remote sensing in monitoring the status of species in data-poor tropical forests.

Fishers' ecological knowledge points to fishing-induced changes in the Peruvian Amazon.

Scientists increasingly draw on fishers' ecological knowledge (FEK) to gain a better understanding of fish biology and ecology, and inform options for fisheries management. We report on a study of FEK among fishers along the Lower Ucayali River in Peru, a region of exceptional productivity and diversity, which is also a major supplier of fish to the largest city in the Peruvian Amazon. Given a lack of available scientific information on stock status, we sought to identify temporal changes in the composition and size of exploited species by interviewing fishers from 18 communities who vary in years of fishing experience since the mid-1950s. We develop four FEK-based indicators to assess changes in the fish assemblage and compare findings with landings data. We find an intensification of fishing gear deployed over time and spatiotemporal shifts in the fish assemblage and reported declines in species weight, which point to a fishing-down process with declines across multiple species. This finding is reflected in a shifting baseline among our participants, whereby younger generations of fishers have different expectations regarding the distribution and size of species. Our study points to the importance of spillover effects from the nearby Pacaya-Samira National Reserve and community initiatives to support the regional fishery. Reference to fishers' knowledge also suggests that species decline is likely underreported in aggregated landings data. Despite the dynamism and diversity of Amazonian floodplain fisheries, simple FEK-based indicators can provide useful information for understanding fishing-induced changes in the fish assemblage. Fishers hold valuable knowledge for fishery management and conservation initiatives in the region.

COVID-19 information and self-protective behaviors among rural communities in tropical forests.

BACKGROUND: Health risk communication plays a key role in promoting self-protective measures, which are critical in suppressing COVID-19 contagion. Relatively little is known about the communication channels used by rural poor populations to learn novel measures and their effectiveness in promoting self-protective behaviors. Behavioral change can be shaped by people's trust in government institutions which may be differentiated by social identity, including indigeneity. METHODS: During an early phase of the pandemic, we conducted two telephone surveys with over 460 communities - both Indigenous and mestizo - without road access and limited communication access in the Peruvian Amazon. This is the first report on the association of information sources about self-protective measures against COVID-19 with the adoption of self-protective behaviors in remote rural areas in developing countries. RESULTS: People mainly relied on mass media (radio, television, newspapers) and interpersonal sources (local authorities, health workers, neighbors/relatives) for information and adopted handwashing, mask-wearing, social distancing, and social restrictions to varying degrees. Overall, self-protective behaviors were largely positively and negatively associated with mass media and interpersonal sources, respectively, depending on the source-measure combination. Mistrust of the government seems to have shaped how Indigenous and mestizo peoples distinctively responded to interpersonal information sources and relied on mass media. CONCLUSIONS: Our findings call for improved media access to better manage pandemics in rural areas, especially among remote Indigenous communities.

Levels of 1-hydroxypyrene in urine of people living in an oil producing region of the Andean Amazon (Ecuador and Peru).

PURPOSE: Polycyclic aromatic hydrocarbons (PAHs) are contaminants with carcinogenic effects but little is known about their presence in environments surrounding oil drilling operations and spills or exposure levels in nearby communities. The objective of this study was to characterize PAH levels in people living near oil drilling operations in relation to fish consumption, occupation, source of water and other socio-demographic characteristics. METHODS: This pilot study examined PAH exposure by measuring 1-hydroxypyrene (1-OHP) in urine samples using high-performance liquid chromatography and fluorescence detection from 75 women and men in the Ecuadorian and Peruvian Amazon living near oil drilling operations and who answered a questionnaire collecting socio-demographic, occupational and dietary information. Data were analyzed using multiple linear regression models. RESULTS: The mean value of 1-OHP was 0.40 µmol/mol creatinine, 95% CI 0.32-0.46 µmol/mol creatinine. Women who used water from a surface source (for washing clothes or bathing) had almost twice the amount of 1-OHP in their urine (mean 1-OHP = 0.41 µmol/mol creatinine, 95% CI 0.28-0.54 µmol/mol creatinine, n = 23) as women who used water from either a well, a spring or rain (mean 1-OHP = 0.22 µmol/mol creatinine, 95% CI 0.11-0.34 µmol/mol creatinine, n = 6). Men who reported eating a bottom-dwelling species as their most commonly consumed fish (mean 1-OHP = 0.50 µmol/mol creatinine, 95% CI 0.36-0.64 µmol/mol creatinine, n = 31) had twice as much 1-OHP in their urine as men who reported a pelagic fish (mean 1-OHP = 0.25 µmol/mol creatinine, 95% CI 0.15-0.35 µmol/mol creatinine, n = 15), signaling either oral (fish consumption) or dermal (while standing in water fishing benthic species) exposure. CONCLUSIONS: More contact with surface water and benthic fish may result in higher levels of 1-OHP in human urine among the study population. Reducing the amount of oil and wastes entering the waterways in Andean Amazonia would be one way to reduce exposure.

Cropping history trumps fallow duration in long-term soil and vegetation dynamics of shifting cultivation systems.

In the study of shifting cultivation systems, fallow duration is seen as the key determinant of vegetation and soil dynamics: long fallows renew soil fertility, biomass, and biodiversity. However, long fallow systems are increasingly replaced around the world with short-medium fallow systems, and awareness is growing of the need to look across multiple (not just single) crop-fallow cycles to accurately understand observed soil and vegetation patterns. In a study from Peru that builds on 50+ years of field-level land-use histories, we found that, over multiple crop-fallow cycles, farmers' cropping practices mattered more than fallow duration for biodiversity and soil fertility. After initial clearing of primary forest, a precipitous decline occurred in tree species richness of fallows (>50%) with gradual but continued loss thereafter (~0.5 species/yr), which resulted in shifts in species composition over time. For soils, the decline in fertility was more gradual with each additional cycle of cropping resulting in lowered soil organic matter, available phosphorus, and exchangeable sodium levels, even in fields with long fallow durations. In the most intensively used sites, soils experienced a 16% decline of soil organic matter over 4+ cycles. In contrast to previous studies, biomass accumulation and carbon stocks were not related to cropping history or to the number and duration of cycles observed. This suggests that biodiversity-soils-biomass dynamics may not necessarily "move together" in these systems. These results point to the importance of the number of crop-fallow cycles over fallow duration in driving soil fertility and vegetation dynamics under shifting cultivation in the Peruvian Amazon. Overtime shifting cultivation may erode soil fertility and biodiversity levels even if long fallows persist. As the decline in soils appears slow, it may be possible to address this effect with the use of amendments, however biodiversity declines and species compositional changes may be much harder to reverse.

Mercury concentrations in urine of amerindian populations near oil fields in the peruvian and ecuadorian amazon.

BACKGROUND: Mercury is a global contaminant with toxic, persistent effects on human health. Petroleum extraction is an important source of elemental mercury; little is known about human exposure levels near oil fields in the Amazon basin. OBJECTIVES: To characterize mercury levels in people living near oil production sites in the Peruvian and Ecuadorian Amazon, controlling for fish consumption, occupation, source of water and socio-demographic characteristics. METHODS: Analyze mercury levels in urine samples using cold vapour atomic fluorescence spectrometry from 76 indigenous men and women in eight riverine communities situated near oil wells or pipelines. Subjects answered a questionnaire soliciting socio-demographic, occupational and dietary information. Data were analyzed using multiple linear regression modeling. RESULTS: The mean value of U-Hg was 2.61µg/g creatinine (95% CI: 2.14-3.08), with 7% of the sample recording values above the global background standard suggested by The World Health Organization (5µg/g creatinine). Women who used water from a surface source had two and a half times the amount of mercury in their urine (mean=3.70µg/g creatinine, 95% CI: 2.26-5.15) compared with women who used other water sources (mean =1.39µg/g creatinine, 95% CI: 0.51-2.25). Men who were involved in an oil clean-up operation had twice as much mercury in their urine (mean =3.07µg/g creatinine, 95% CI: 1.97-4.16) as did those who worked on other tasks (mean =1.56µg/g creatinine, 95% CI: 1.48-2.65). Mercury levels were not associated with the number of fish meals per week. CONCLUSIONS: Indigenous peoples of the Peruvian and Ecuadorian Amazon living near oil production sites generally had urine mercury levels within the global background standard suggested by the World Health Organization. Increased levels of mercury in urine were detected for men involved in oil spill remediation and for women who relied on surface water for household needs. These findings signal the need for strict safety measures to limit the amount of oil entering the waterways in Andean Amazonia so as to protect the health of indigenous people.

Mercury Contamination in an Indicator Fish Species from Andean Amazonian Rivers Affected by Petroleum Extraction.

Elevated mercury (Hg) concentrations in fish from Amazonia have been associated with gold-mining, hydroelectric dams and deforestation but few studies consider the role of petroleum extraction. Hg levels were determined in fish samples collected in three river basins in Ecuador and Peru with contrasting petroleum exploitation and land-use characteristics. The non-migratory, piscivorous species, Hoplias malabaricus, was used as a bioindicator. The rate of Hg increase with body weight for this species was significantly higher on the Corrientes River, near the site of a recent oil spill, than on the other two rivers. In the absence of substantial deforestation and other anthropogenic sources in the Corrientes River basin, this finding suggests that oil contamination in Andean Amazonia may have a significant impact on Hg levels in fish.

Climate-related disaster opens a window of opportunity for rural poor in northeastern Honduras.

Two distinct views are evident in research on how rural communities in developing countries cope with extreme weather events brought by climate change: (i) that the resource-reliant poor are acutely vulnerable and need external assistance to prepare for such events, and (ii) that climate-related shocks can offer windows of opportunity in which latent local adaptive capacities are triggered, leading to systemic improvement. Results from a longitudinal study in a Tawahka community in Honduras before and after Hurricane Mitch (1994-2002) indicate that residents were highly vulnerable to the hurricane--due in part to previous development assistance--and that the poorest households were the hardest hit. Surprisingly, however, the disaster enabled the poor to initiate an institutional change that led to more equitable land distribution, slowed primary forest conversion, and positioned the community well to cope with comparable flooding occurring 10 y later. The study provides compelling evidence that communities can seize on the window of opportunity created by climate-induced shocks to generate sustained social-ecological improvement, and suggests that future interventions should foster local capacities for endogenous institutional change to enhance community resilience to climate shocks.

Land-use poverty traps identified in shifting cultivation systems shape long-term tropical forest cover.

In this article we illustrate how fine-grained longitudinal analyses of land holding and land use among forest peasant households in an Amazonian village can enrich our understanding of the poverty/land cover nexus. We examine the dynamic links in shifting cultivation systems among asset poverty, land use, and land cover in a community where poverty is persistent and primary forests have been replaced over time--with community enclosure--by secondary forests (i.e., fallows), orchards, and crop land. Land cover change is assessed using aerial photographs/satellite imagery from 1965 to 2007. Household and plot level data are used to track land holding, portfolios, and use as well as land cover over the past 30 y, with particular attention to forest status (type and age). Our analyses find evidence for two important types of "land-use" poverty traps--a "subsistence crop" trap and a "short fallow" trap--and indicate that the initial conditions of land holding by forest peasants have long-term effects on future forest cover and household welfare. These findings suggest a new mechanism driving poverty traps: insufficient initial land holdings induce land use patterns that trap households in low agricultural productivity. Path dependency in the evolution of household land portfolios and land use strategies strongly influences not only the wellbeing of forest people but also the dynamics of tropical deforestation and secondary forest regrowth.

COVID-19 and protection measures adopted in rural amazon communities during the first months of the pandemic. / COVID-19 y medidas de protección adoptadas en comunidades rurales amazónicas durante los primeros meses de la pandemia.

BACKGROUND: Motivation for the study. To document the evolution of COVID-19 in rural Amazonian populations, which are still little known. BACKGROUND: Main findings. COVID-19 spread rapidly through rural communities, initially spreading to mestizo hamlets and later affecting indigenous communities. Rural mortality varied by region and ethnicity. Social distancing was difficult, and travel to receive government vouchers contributed to contagion. BACKGROUND: Implications. Identifying the factors that contributed to contagion and the barriers to the adoption of protective measures in rural Amazonian populations will help to face future pandemics. OBJECTIVES.: To analyze the evolution of COVID-19 in rural populations of Loreto and Ucayali in the early stage of the pandemic. MATERIALS AND METHODS.: A community-level longitudinal observational study was conducted and based on two rounds of telephone surveys with local authorities of more than 400 indigenous and non-indigenous rural communities in Loreto and Ucayali, in July and August 2020. We collected information on cases and deaths by COVID-19 in their communities, protective measures adopted and if state assistance was received in the early stage of the pandemic. Descriptive statistics allowed us to evaluate the evolution of the pandemic after the initial outbreak and compare the trends of the two regions, as well as between indigenous and non-indigenous populations. RESULTS.: In July 2020, COVID-19 had reached 91.5% of the communities, although deaths from COVID-19 were reported in 13.0% of the communities, with rural mortality being higher in Ucayali (0.111%) than in Loreto (0.047%) and in non-indigenous communities. By August, prevalence decreased from 44.0% to 32.0% of communities, but became more frequent in indigenous communities, and those in Ucayali. Traveling to the city to receive state bonuses and difficulties maintaining social distancing contributed to the spread. CONCLUSIONS.: Our findings show the evolution of COVID-19 in rural communities and point to important areas of attention in future public policies, for the adoption of protective measures and reconsidering strategies for the distribution of assistance in the face of future pandemics. BACKGROUND: Motivation for the study. To document the evolution of COVID-19 in rural Amazonian populations, which are still little known. BACKGROUND: Main findings. COVID-19 spread rapidly through rural communities, initially spreading to mestizo hamlets and later affecting indigenous communities. Rural mortality varied by region and ethnicity. Social distancing was difficult, and travel to receive government vouchers contributed to contagion. BACKGROUND: Implications. Identifying the factors that contributed to contagion and the barriers to the adoption of protective measures in rural Amazonian populations will help to face future pandemics.

OBJETIVOS.: Analizar la evolución del COVID-19 en poblaciones rurales de Loreto y Ucayali en la etapa temprana de la pandemia. MATERIALES Y MÉTODOS.: Se realizó un estudio observacional longitudinal a nivel de comunidades basado en dos rondas de encuestas telefónicas con autoridades locales de más de 400 comunidades rurales indígenas y no-indígenas en Loreto y Ucayali, en julio y agosto de 2020, para recopilar información sobre casos y muertes por COVID-19 en sus comunidades, medidas de protección adoptadas y la recepción de asistencia estatal en la etapa temprana de la pandemia. Estadísticas descriptivas permiten evaluar la evolución de la pandemia después del brote inicial y comparar las tendencias de las dos regiones, así como entre poblaciones indígenas y no-indígenas. RESULTADOS.: En julio de 2020, el COVID-19 había llegado al 91,5% de las comunidades, aunque se reportaron muertes por COVID-19 en 13,0% de las comunidades, siendo la mortalidad rural mayor en Ucayali (0,111%) que en Loreto (0,047%) y en comunidades no-indígenas. Para agosto, la prevalencia disminuyó de 44,0% a 32,0% de comunidades, pero se volvió más frecuente en las comunidades indígenas, y aquellas en Ucayali. Viajar a la ciudad para recibir bonos estatales y las dificultades para mantener el distanciamiento social contribuyeron al contagio. CONCLUSIONES.: Los hallazgos mostraron la evolución del COVID-19 en comunidades rurales y señalan áreas importantes de atención en futuras políticas públicas, para la adopción de medidas de protección y reconsiderar estrategias para la distribución de asistencia ante pandemias futuras. BACKGROUND: Motivación para realizar el estudio. Documentar la evolución del COVID-19 en poblaciones rurales Amazónicas, las cuales son aún poco conocidas. BACKGROUND: Principales hallazgos. El COVID-19 se propagó rápidamente por las comunidades rurales, extendiéndose inicialmente por los caseríos mestizos y después afectando a comunidades indígenas. La mortalidad rural varió por región y por etnia. El distanciamiento social fue difícil y los viajes para recibir bonos estatales contribuyeron al contagio. BACKGROUND: Implicancias. Conocer los factores que contribuyeron al contagio y las barreras para la adopción de medidas de protección en poblaciones rurales Amazónicas ayudarán a enfrentar pandemias futuras.

COVID-19 contagion across remote communities in tropical forests.

Understanding COVID-19 contagion among poor populations is hampered by a paucity of data, and especially so in remote rural communities with limited access to transportation, communication, and health services. We report on the first study on COVID-19 contagion across rural communities without road access. We conducted telephone surveys with over 400 riverine communities in the Peruvian Amazon in the early phase of the pandemic. During the first wave (April-June, 2020), COVID-19 spread from cities to most communities through public and private river transportation according to their remoteness. The initial spread was delayed by transportation restrictions but at the same time was driven in unintended ways by government social assistance. During the second wave (August, 2020), although people's self-protective behaviors (promoted through communication access) helped to suppress the contagion, people responded to transportation restrictions and social assistance in distinct ways, leading to greater contagion among Indigenous communities than mestizo communities. As such, the spatial contagion during the early phase of the pandemic in tropical forests was shaped by river transportation and social behaviors. These novel findings have important implications for research and policies on pandemics in rural areas.

Geolocation of unpublished archaeological sites in the Peruvian Amazon.

Published maps identifying archaeological sites in the Amazon basin show a paucity of sites in western Amazonia compared to the Brazilian Amazon. Whereas fewer than two dozen are identified for the Peruvian Amazon on basin-wide maps, a thorough review of unpublished archival material held by the Ministry of Culture of Peru and other sources revealed more than 400 known but unpublished sites in the Department of Loreto, challenging the notion that the region was sparsely occupied in prehistory. Our database provides the geolocation of each site and corresponding references for use by scientists seeking to better understand regional Pre-Columbian human occupation and settlement, cultural change, resource use and their landscape legacies. These data are foundational not only to the development of a richer understanding of prehistory and historical ecology of the Amazon basin but importantly for informing current land use, forest conservation and development policies as well as initiatives to support indigenous land and cultural rights in Amazonia.

Are indigenous territories effective natural climate solutions? A neotropical analysis using matching methods and geographic discontinuity designs.

Indigenous Territories (ITs) with less centralized forest governance than Protected Areas (PAs) may represent cost-effective natural climate solutions to meet the Paris agreement. However, the literature has been limited to examining the effect of ITs on deforestation, despite the influence of anthropogenic degradation. Thus, little is known about the temporal and spatial effect of allocating ITs on carbon stocks dynamics that account for losses from deforestation and degradation. Using Amazon Basin countries and Panama, this study aims to estimate the temporal and spatial effects of ITs and PAs on carbon stocks. To estimate the temporal effects, we use annual carbon density maps, matching analysis, and linear mixed models. Furthermore, we explore the spatial heterogeneity of these estimates through geographic discontinuity designs, allowing us to assess the spatial effect of ITs and PAs boundaries on carbon stocks. The temporal effects highlight that allocating ITs preserves carbon stocks and buffer losses as well as allocating PAs in Panama and Amazon Basin countries. The geographic discontinuity designs reveal that ITs' boundaries secure more extensive carbon stocks than their surroundings, and this difference tends to increase towards the least accessible areas, suggesting that indigenous land use in neotropical forests may have a temporarily and spatially stable impact on carbon stocks. Our findings imply that ITs in neotropical forests support Nationally Determined Contributions (NDCs) under the Paris Agreement. Thus, Indigenous peoples must become recipients of countries' results-based payments.

Human modification of a large meandering Amazonian river: genesis, ecological and economic consequences of the Masisea cutoff on the central Ucayali, Peru.

Evidence is mounting regarding the significant extent and scope of long-term human modification of "pristine nature" in the neotropics. In Amazonia, recent studies point to the landscape imprint of human activity that has transformed the forests, savannas, soils, and waterways of the basin. In this report, we describe a massive meander cutoff in the Peruvian Amazon along the Ucayali River--the fifth-longest river in the Amazon basin--that was triggered by small-scale human actions and resulted in significant ecological and economic consequences for the region. The modern case of the Masisea cutoff-near the Amazonian port city of Pucallpa, Peru (285,000 inhabitants)-indicates that humans using simple tools can play a major role in transforming large meandering rivers and their floodplains.

COVID-19 y medidas de protección adoptadas en comunidades rurales amazónicas durante los primeros meses de la pandemia / COVID-19 and protection measures adopted in rural amazon communities during the first months of the pandemic

RESUMEN Objetivos. Analizar la evolución del COVID-19 en poblaciones rurales de Loreto y Ucayali en la etapa temprana de la pandemia. Materiales y métodos. Se realizó un estudio observacional longitudinal a nivel de comunidades basado en dos rondas de encuestas telefónicas con autoridades locales de más de 400 comunidades rurales indígenas y no-indígenas en Loreto y Ucayali, en julio y agosto de 2020, para recopilar información sobre casos y muertes por COVID-19 en sus comunidades, medidas de protección adoptadas y la recepción de asistencia estatal en la etapa temprana de la pandemia. Estadísticas descriptivas permiten evaluar la evolución de la pandemia después del brote inicial y comparar las tendencias de las dos regiones, así como entre poblaciones indígenas y no-indígenas. Resultados. En julio de 2020, el COVID-19 había llegado al 91,5% de las comunidades, aunque se reportaron muertes por COVID-19 en 13,0% de las comunidades, siendo la mortalidad rural mayor en Ucayali (0,111%) que en Loreto (0,047%) y en comunidades no-indígenas. Para agosto, la prevalencia disminuyó de 44,0% a 32,0% de comunidades, pero se volvió más frecuente en las comunidades indígenas, y aquellas en Ucayali. Viajar a la ciudad para recibir bonos estatales y las dificultades para mantener el distanciamiento social contribuyeron al contagio. Conclusiones. Los hallazgos mostraron la evolución del COVID-19 en comunidades rurales y señalan áreas importantes de atención en futuras políticas públicas, para la adopción de medidas de protección y reconsiderar estrategias para la distribución de asistencia ante pandemias futuras.

ABSTRACT Objectives. To analyze the evolution of COVID-19 in rural populations of Loreto and Ucayali in the early stage of the pandemic. Materials and methods. A community-level longitudinal observational study was conducted and based on two rounds of telephone surveys with local authorities of more than 400 indigenous and non-indigenous rural communities in Loreto and Ucayali, in July and August 2020. We collected information on cases and deaths by COVID-19 in their communities, protective measures adopted and if state assistance was received in the early stage of the pandemic. Descriptive statistics allowed us to evaluate the evolution of the pandemic after the initial outbreak and compare the trends of the two regions, as well as between indigenous and non-indigenous populations. Results. In July 2020, COVID-19 had reached 91.5% of the communities, although deaths from COVID-19 were reported in 13.0% of the communities, with rural mortality being higher in Ucayali (0.111%) than in Loreto (0.047%) and in non-indigenous communities. By August, prevalence decreased from 44.0% to 32.0% of communities, but became more frequent in indigenous communities, and those in Ucayali. Traveling to the city to receive state bonuses and difficulties maintaining social distancing contributed to the spread. Conclusions. Our findings show the evolution of COVID-19 in rural communities and point to important areas of attention in future public policies, for the adoption of protective measures and reconsidering strategies for the distribution of assistance in the face of future pandemics.

Risk of malaria transmission from fish ponds in the Peruvian Amazon.

BACKGROUND: The contribution made by fish ponds (pisciculture) to malaria transmission in the Peruvian Amazon remains to be confirmed. Recent entomological evidence indicates that Anopheles darlingi, the main malaria vector in the region, is frequently found in fish ponds along the Iquitos-Nauta road (Loreto, Peru). The aim of this study was to quantify the effect of fish pond density on malaria occurrence. METHODS: A retrospective 30-month cohort study was conducted in eight communities along the Iquitos-Nauta road. Malaria incidence was ascertained from malaria registries of the local health post, which consist of data from both active and passive surveillance (247 cases). Fish pond density was measured using an interpreted satellite image and information on potential confounders was collected through interviewer-administered questionnaires. RESULTS: A total of 1018 individuals from 234 eligible households (90% of the 259 total number of households in the study area) provided complete information on exposures and outcome. Fish pond density was found to be a significant predictor of malaria occurrence (aOR=1.23; 95% CI: 1.09-1.38). CONCLUSION: The association between fish pond density and malaria suggests that fish ponds contribute to malaria transmission in the region. These results have important implications for the prevention and control of malaria and the development of pisciculture as an important economic activity in Amazonia and beyond.