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•The federal grants and scholarships are uneven distributed between Brazilian regions.•The North region receives the least number of scholarships and grants per km² in Brazil.•The ...current federal budget is insufficient to cover large-scale research in the Amazon.•New national and international funds need to be created to improve Amazon biodiversity research.
The Brazilian Amazon is one of Earth’s most biodiverse and ecologically important regions. However, research investments for biodiversity in the biome are disproportionately low compared with other regions of Brazil. In 2022, the Amazon received 13% of master's, doctoral and postdoctoral scholarships and hosted 11% of all researchers working in biodiversity postgraduate programs. Amazonian institutions received approximately 10% of all federal budget spent on grants and scholarships and about 23% of all resources destined to support long-term ecological sites. The cities of Manaus and Belém concentrate about 90% of all grants and scholarships available for the entire region. Despite per capita research investment in the Amazon being equal to or better than that available for the more economically developed regions of Brazil, the distribution of resources by area is highly unequal. Increasing research funding for the Amazon region requires differential input by federal agencies and more transnational collaborations and integration between Amazonian programs and international funds.
Land-cover change can affect inland fisheries, which underpin food security of millions of people worldwide. Removal of forests from very large floodplains has been found to decrease fish catch via ...loss of feeding and nursery habitat for fish. However, it is unknown if similar effects occur in smaller rivers with limited floodplain areas. Little is also known about the mechanisms by which land-cover changes affect inland fish catch. Here, we assessed land-use and land-cover (LULC) effects on fish catch, diet, and condition at sites in two medium-sized rivers of Cameroon, in Central Africa. We found that LULC explained 30% of the variation in fish catch, with the catch of five species being positively, and of two species being negatively, related to floodplain forests. The niche breadth of fish diets was higher in the river surrounded by forests than in the river surrounded by agricultural land. However, contrary to expectations, condition of the fish, as indicated by occurrence of diseases or deformities, eroded fins, lesions or tumors, was not related to LULC. Our results support the notions that floodplain forests support fish populations in rivers with limited floodplain areas in ways similar to that of rivers with large floodplains, and that LULC affects fish populations via changes in fish diets and instream habitat features (i.e., riparian canopy closure, water clarity, substrate heterogeneity, and habitat volume). These effects imply that prevailing changes in LULC threaten the food and livelihood security services provided by inland fisheries, highlighting the importance of policies that maintain native vegetation along riverbanks and in floodplain areas.
•Changes in land-use and land-cover (LULC) can affect inland fish populations.•How changes in LULC affect fish catch, diet, and condition in small rivers is unstudied.•LULC affects fish catch in medium-sized rivers through changes in floodplain forest extent.•Such effects appear to involve fish diets and instream habitat.
Species of the genus Pseudoplatystoma, the long-whiskered catfishes, are important in commercial and recreational fisheries in South America, and some species have become key to regional aquaculture. ...Some species of the genus are under pressure due to overfishing and the negative impacts of dams. Six questions are asked in this review: (i) What species are in the genus, and where are they distributed? (ii) What are the life histories and ecologies of Pseudoplatystoma species? (iii) What are the patterns of somatic growth for these species? (iv) What is known about the biomass, production, and population dynamics of Pseudoplatystoma? (v) What is the geographic distribution of genetic variation within Pseudoplatystoma species? (vi) What are the threats to the conservation of these species? The taxonomy of the genus currently includes eight species, respectively, distributed over the Orinoco, Amazon, Paraná, and São Francisco basins. Pseudoplatystoma catfishes typically exhibit longitudinal migrations for reproduction and lateral migration for feeding, but these patterns may vary among populations. The size of the first maturation of these catfishes varies between 57 cm to 82 cm in total length. Five of the eight species spawn during the rising water season. Pseudoplatystoma species can grow to about 130 cm in total length and 100 Kg in weight and live until 30 years of age, depending upon the species. Biomass production and population dynamics of these catfishes have not yet been fully described. Their life-history characteristics indicate that they are periodic strategists with associated population recruitment dynamics. Population genetic patterning varies among Pseudoplatystoma species, with some degree of homing behavior and genetic differentiation among populations, indicating the need for management by applying the Management Unit and perhaps Evolutionary Significant Unit concepts. The main threats to the persistence of these catfishes are overfishing and alterations in and obstruction of river flow due to the construction of hydropower dams. After synthesizing existing information on species of the genus Pseudoplatystoma, we offer suggestions for future research to fill critical gaps in the knowledge of this group.
Co-management is increasingly recognized as an effective model for managing fisheries, but little information exists on whether co-management can produce effects in species other than the target ...species. Fishery co-management in the tropics, where fish diversity is high and fish catches tend to be multispecies, is prone to produce assemblage-wide effects via alterations in the food web and changes in the overall capture of non-target species. Here, we assessed the effects of co-management for the species
Arapaima
sp. in relation to the structure and composition of the overall fish assemblage in floodplain lakes of the central Amazon Basin. These floodplain lakes are managed under a system of zoning of fishing activities. We used data from surveys of six floodplain lakes, including two lakes of each of three categories (lakes where fishing is prohibited, limited-access lakes, and open fishing lakes). The surveys were carried out before and after implementation of co-management, through gillnet fishing. The study area was the lower Solimões River, in the Amazon Basin, Brazil. Statistical models showed significant changes in the composition and structure of the fish assemblages after the implementation of the co-management, regardless of the zoning category. Through regulation of gear use and fishing practices, co-management allowed the colonization of species that had not been present before, which lead to higher richness and consequently increased fish sizes, abundance and biomass. Species of sedentary habits, migrants of short and medium distances, with commercial importance benefited the most from co-management. In the results presented in temporal scale, it was possible to observe a potential spillover effect being provided by the lakes where fishing is prohibited (no-take zones) and those of limited access that benefited those open to fishing. Thus, co-management had positive effects in the structure and composition of fish assemblages in all lakes, regardless of zoning category.
Coral reef fisheries are important as they support the economy, livelihoods, and food security of millions of people worldwide. However, reef fisheries are widely overfished, impacting the abundance ...and size structure of highly biodiverse fish assemblages. Here, we assessed the effects of fishing on the size structure of exploited coral reef fishes using size spectra analysis, a method that informs about fishing mortality and ecosystem productivity. We used data from over 500 landing site interviews with hook and line fishers in Northeastern Brazil. The data included 18 fishing grounds (i.e., fringing reefs), fishing effort (fishers/km2) of a widely used gear (hooks and line), and 3690 measurements of exploited fish body size. We fitted linear regressions to body size estimates in the catch of each fishing ground to estimate the slopes of the size spectra and tested for a possible effect of fishing effort on those slopes. We found that fishing effort associated with hook and line negatively affected the slopes of size spectra (p = 0.04; R2 = 0.22). This likely occurred because hook and line generally selects for the largest individuals in the assemblage, so that, as expected, higher levels of fishing effort were associated with smaller size of the exploited fishes. Given body size is usually proportional to trophic level in reef fishes, our finding suggests fishing may be disproportionately affecting predators in the study area. Our study provides the first documentation of fishing impacts on the size structure of coral reef fishes exploited by a predominant gear type in Northeastern Brazil, establishing a baseline for future monitoring of fishing impacts and contributing to the development of sustainable fisheries management strategies.
•Fishing negatively affected the size of reef fish assemblages of the Atlantic.•Vulnerable species must be prioritized in management initiatives.•Fisheries management must aim at maintaining the diversity of functional roles.
Construction of hydroelectric dams affect river ecosystems, fish diversity, and fisheries yields. However, there are no studies assessing the combined effects on fish caused by several adjacent dams ...and their reservoirs, as in a ‘dam cascade’. This study predicts the potential effects that a cascade of ten dams currently under construction in the upper Yangtze River in China will have on local fishes, and uses such predictions to assess the effectiveness of possible fish conservation measures. We found that the dam cascade will have serious combined effects on fishes mainly due to impoundment, habitat fragmentation and blocking, flow regime modification, and hypolimnetic discharges. The impoundments will cause loss of critical habitats for 46 endemic species. The dams will fragment the populations of 134 species and will block migration routes for 35 potamodromous fishes. Corieus guichenoti will have a high risk of extinction due to the combined effects of impoundment and blocking. Modification of the flow regime will adversely affect the recruitment of 26 species that produce drifting eggs. The start of annual spawning for 13 fishes will be postponed by more than 1 month, and fish spawning and growth opportunities will be reduced due to low water temperatures associated with hypolimnetic discharges. Combined dam effects will further reduce the likelihood of successful recruitment of some endangered species, such as Acipenser dabryanus and Psephurus gladius. Three countermeasures hold promise to mitigate the near-term effects of the dam cascade, including preservation and rehabilitation of critical habitat, restoration of a semi-natural flow regime, and stock enhancement that respects genetic integrity. These conclusions can guide the development of protection plans for fishes in the upper Yangtze River. The approach undertaken in this study—by which the known and likely effects of present and future dams were simultaneously considered in light of the biology of the species—highlights the usefulness of ichthyology for fish conservation.
The recent 70% decline in deforestation in the Brazilian Amazon suggests that it is possible to manage the advance of a vast agricultural frontier. Enforcement of laws, interventions in soy and beef ...supply chains, restrictions on access to credit, and expansion of protected areas appear to have contributed to this decline, as did a decline in the demand for new deforestation. The supply chain interventions that fed into this deceleration are precariously dependent on corporate risk management, and public policies have relied excessively on punitive measures. Systems for delivering positive incentives for farmers to forgo deforestation have been designed but not fully implemented. Territorial approaches to deforestation have been effective and could consolidate progress in slowing deforestation while providing a framework for addressing other important dimensions of sustainable development.
Small-scale fisheries (SSF) account for much of the global fish catch, but data to assess them often do not exist, impeding assessments of their historical dynamics and status. Here, we propose an ...approach to assess 'data-less' SSF using local knowledge to produce data, life history theory to describe their historical multispecies dynamics, and length-based reference points to evaluate stock status. We demonstrate use of this approach in three data-less SSFs of the Congo Basin. Fishers' recalls of past fishing events indicated fish catch declined by 65–80% over the last half-century. Declines in and depletion of many historically important species reduced the diversity of exploited species, making the species composition of the catch more homogenous in recent years. Length-at-catch of 11 of the 12 most important species were below their respective lengths-at-maturity and optimal lengths (obtained from Fishbase) in recent years, indicating overfishing. The most overfished species were large-bodied and found in the Congo mainstem. These results show the approach can suitably assess data-less SSF. Fishers' knowledge produced data at a fraction of the cost and effort of collecting fisheries landings data. Historical and current data on fish catch, length-at-catch, and species diversity can inform management and restoration efforts to curb shifting baselines of these fisheries. Classification of stock status allows prioritizing management efforts. The approach is easy to apply and generates intuitive results, having potential to complement the toolkits of researchers and managers working in SSF and engage stakeholders in decision-making processes.
Analysis of small-scale inland fisheries (SSIFs) is often highly dispersed and tends not reflect the true magnitude of their contribution to society. This is partly due to the insufficient attention ...given to this sector by the relevant authorities, in addition to its highly diverse characteristics, with complex patterns of operation in a wide range of systems, often in remote areas. Here, by integrating fishers as participatory fishery monitors, we provide fishery-dependent estimates of yields, the biological attributes of the fish species, and the spatiotemporal dynamics of the fisheries of lakes on the floodplain of the São Francisco basin in northeastern Brazil. As the fishers were willing participates in the monitoring, the results revealed well-structured artisanal fishing activities, with the lake system providing high-profile fish harvests from both monthly and annual perspectives. The spatial distribution of fishing effort reflected the adaptation of the fishers to the flood cycle of the river, in order to maintain high fishery productivity throughout the year. The results also indicate that participatory monitoring can help to overcome knowledge gaps and provide a database that is readily applicable to management needs at both local and regional scales. As Brazil is one few world’s nations that no longer have national fishing monitoring program, participatory monitoring represents a low-cost solution for the credible and useful data on small-scale fisheries. It would thus appear to be extremely worthwhile to invest in the empowerment of communities in order to overcome the historic vulnerability of productive sector and the food security of the populations that depend on these fisheries.
1. Habitat degradation leads to biodiversity loss and concomitant changes in ecosystem processes. Tropical river floodplains are highly threatened by land cover changes and support high biodiversity ...and important ecosystem services, but the extent to which changes in floodplain land cover affect fish biodiversity remains unknown. 2. We combined fish and environmental data collected in situ and satellite-mapped landscape features to evaluate how fish species with different ecological strategies and assemblage structures respond to deforestation in floodplains of the Amazon River. We surveyed 462 floodplain habitats distributed along a gradient of land cover, from largely forested to severely deforested. Rather than analyse only taxonomic metrics, we employed an integrative approach that simultaneously considers different aspects of fish biodiversity (i.e. β diversity and taxonomic and functional assemblage structure) to facilitate mechanistic interpretations of the influence of land cover. 3. Spatial patterns of fish biodiversity in the Amazon River floodplain were strongly associated with forest cover as well as local environmental conditions linked to landscape gradients. Several species and functional groups defined by life-history, feeding, swimming/microhabitat-use strategies were positively associated with forest cover. Other species, including some that would usually be considered habitat generalists and species directly dependent on autochthonous resources (e.g. planktivores), were most common in areas dominated by herbaceous vegetation or open water habitats associated with the opposite extreme of the forest cover gradient. β diversity and the degree of uniqueness of species combinations within habitats were also positively associated with forest cover. 4. Synthesis and applications. Our results demonstrating that spatial patterns of fish biodiversity are associated with forest cover, indicate that deforestation of floodplains of the Amazon River results in spatial homogenization of fish assemblages and reduced functional diversity at both local and regional scales. Floodplains world-wide have undergone major land cover changes, with forest loss projected to increase during the next decades. Conserving fish diversity in these ecosystems requires protecting mosaics of both aquatic habitats and floodplain vegetation, with sufficient forest cover being critically important.
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