N. N. Fabré

Fish and aquatic habitat conservation in South America: a continental overview with emphasis on neotropical systems.

Fish conservation in South America is a pressing issue. The biodiversity of fishes, just as with all other groups of plants and animals, is far from fully known. Continuing habitat loss may result in biodiversity losses before full species diversity is known. In this review, the main river basins of South America (Magdalena, Orinoco, Amazon and Paraná-La Plata system), together with key aquatic habitats (mangrove-fringed estuaries of the tropical humid, tropical semi-arid and subtropical regions) are analysed in terms of their characteristics and main concerns. Habitat loss was the main concern identified for all South American ecosystems. It may be caused by damming of rivers, deforestation, water pollution, mining, poor agricultural practice or inadequate management practice. Habitat loss has a direct consequence, which is a decrease in the availability of living resources, a serious social and economic issue, especially for South American nations which are all developing countries. The introduction of exotic species and overfishing were also identified as widespread across the continent and its main freshwater, coastal and marine ecosystems. Finally, suggestions are made to find ways to overcome these problems. The main suggestion is a change of paradigm and a new design for conservation actions, starting with integrated research and aiming at the co-ordinated and harmonized management of the main transboundary waters of the continent. The actions would be focused on habitat conservation and social rescue of the less well-off populations of indigenous and non-indigenous peoples. Energy and freshwater demands will also have to be rescaled in order to control habitat loss.

Tropical Artisanal Coastal Fisheries: Challenges and Future Directions

Artisanal fisheries occur all over the tropics and provide an important source of protein and income for many coastal communities. However, varied types and magnitudes of anthropogenic impacts threaten the environmental, economic, and socio-cultural sustainability of this poorly studied fishing practice. This article reviews the scattered literature on tropical artisanal coastal fisheries, identifying key challenges to ensure future sustainability. Despite huge data shortfalls, there is considerable evidence that artisanal fisheries have a significant influence on the distribution and abundance of target and by-catch species, in addition to wider impacts on biodiversity, biomass, assemblage structure, community dynamics, and ecosystem functioning. Despite these immediate and considerable threats, regulation and management of artisanal fisheries are problematic. Local communities in the coastal tropics are frequently very poor, and families frequently rely on fishing for food security and income. Ensuring social and environmental sustainability therefore entails models of governance that are able to adaptively manage these complex socio-ecological systems. Such models are being developed, but it is unclear whether there are sufficient resources and technical capacity to widely implement them before the widespread collapse of fisheries with potentially serious consequences for the communities that rely on them.

Biologia reprodutiva do Tambaqui, Colossoma macropomum Cuvier, 1818 (Teleostei, Serrasalmidae), no baixo Amazonas, Brasil

This study analysed the reproductive biology of the tambaqui Colossoma macropomum in the Lower Amazon. 1232 individuals were collected from October 1994 to February 1996 from landings in Santarem in Para State. Individuals between 20 and 120cm total length were weighted, measured, sexed and classified according to their maturity stage. Fecundity and spawning type were determined to analysing intra-ovarian oocytes of 10 adult females. Colossoma macropomum is a total spawner. There are changes at different levels: macro and microscopic cycles according to hydrological periods. Mature individuals occurred between november and february, indicating that spawning take place during this period, at the beginning of flood. The sexual rate changes with the size of fishes. Males are more frequent between 40 and 75cm, and the females between 80 and 115cm. The length/weight relationship indicates differences in the growth between males and females. The average fecundity was estimated on 1.007.349 eggs per female. There is a significant relationship between fecundity and total weight. The equation founded to tambaqui in the Lower Amazon was F = 885347 + 9,16 W1.

Temporal and spatial patterns on serra, Scomberomorus brasiliensis (Teleostei, Scombridae), catches from the fisheries on the Maranhão coast, Brazil.

The displacement pattern of the serra, Scomberomorus brasiliensis, in North-eastern Brazil was analyzed from landing data recorded form the fleet fishing serra. Serra fishery has two seasons: from Septemer to February (demersal species plus serra), and from March to August (almost only large amounts of serra). S. brasilienisis relative abundance increases similarly along the coast from March. but decreases first on the West coast from June. Records indicate that serra is near the coast at least until September/October in Eastern grounds. From October to March (strongest spawning season) there is no record of shoals on the coast. We concluded that the Maranhão coast is just a part of the migration circuit of S. brasilienisis that may exceed 300 nautical miles.

Artisanal Fisheries Research: A Need for Globalization?

Given limited funds for research and widespread degradation of ecosystems, environmental scientists should geographically target their studies where they will be most effective. However, in academic areas such as conservation and natural resource management there is often a mismatch between the geographic foci of research effort/funding and research needs. The former frequently being focused in the developed world while the latter is greater in the biodiverse countries of the Global South. Here, we adopt a bibliometric approach to test this hypothesis using research on artisanal fisheries. Such fisheries occur throughout the world, but are especially prominent in developing countries where they are important for supporting local livelihoods, food security and poverty alleviation. Moreover, most artisanal fisheries in the Global South are unregulated and unmonitored and are in urgent need of science-based management to ensure future sustainability. Our results indicate that, as predicted, global research networks and centres of knowledge production are predominantly located in developed countries, indicating a global mismatch between research needs and capacity.

The application of a general time series model to floodplain fisheries in the Amazon

Time series analysis is a common tool in environmental and ecological studies to construct models to explain and forecast serially correlated data. There are several statistical techniques that are used to deal with univariate and multivariate (more than one series) chronological patterns of fisheries data. In this paper, an additive stochastic model is proposed with explicative and predictive features to capture the main seasonal patterns and trends of a fisheries system in the Amazon. The model is constructed on the assumption that the multivariate response variable - vector containing fishery yield of eight periodic species and the total fishery yield - can be decomposed into three terms: an autoregression of the response vector, an exogenous environmental variable (river level), and a seasonal component (significant frequencies obtained by using spectral analysis and the periodogram indicating the regularity of periodic cycles in the natural and fisheries system). The estimation procedure is carried out via maximum likelihood estimation. The model explained, on average, 78% of the variability in yield of the study species. The model represents the optimal solution (minimum mean square mean error) among the class of all multivariate autoregressive processes with exogenous and seasonal variables. Predictions for one period ahead are provided to illustrate how the model works in practice.

A New Framework for Natural Resource Management in Amazonia

The Amazon rainforest has an iconic position in the global conservation movement: not only is it the largest continuous tropical rainforest in the world, but it also encapsulates many of the greatest challenges facing twentieth century conservation. However, while deforestation and its potential impact on global climate systems (Malhi et al. 2008) grab most of the headlines, it is easy to forget that Amazonia is also home to a large and diverse human population (Ribeiro and Fabre 2003). In addition to the remaining indigenous tribes, there are many settlements and scattered communities of fishermen and farmers of mixed ethnic origins. The support and active engagement of these communities in conservation and sustainable resource management is essential for the success of any conservation or sustainable development initiative. Unfortunately, numerous studies have demonstrated that implementation of co-management or community-based management of natural resources is far more difficult to achieve than the abundant rhetoric that promotes it. Moreover, each failed initiative makes it harder to establish the levels of trust and cooperation that are essential ingredients of successful management systems. Even without the handicap of previous failed initiatives, successful community-led management of natural resources is exceedingly complicated and there are many potential barriers to its successful implementation (Brockington et al. 2008): Conflicts over resource use—especially issues such as fishing rights—may prove intractable problems for which mutually satisfactory resolution may not be possible. In this context, participation of local stakeholders may merely give a platform for the legitimization of vested interests in the guise of community aspirations (Cooke and Kothari 2001). Existing or historic political, cultural or administrative structures may not have the flexibility to enable effective local community involvement, and may even result in disempowerment by forcing local stakeholders to interact within an intrinsically biased framework (Cooke and Kothari 2001). There may be insufficient political will to facilitate a move toward participatory management, especially if there are many and competing vested-interests involved. There may be insufficient interest or engagement of the local stakeholder community in the management of the resource to create strong and democratic local organizations. If the participatory process is perceived as being externally imposed and local stakeholders do not fully “buy-in” to it, then the process may break down when the initiative finishes or when financial support is withdrawn. Insufficient time may be allocated for the creation of local organizations and stakeholder groups and/or refinement of the participatory process. As a consequence of these limitations, well-meaning attempts at promoting co-management of natural resources have often increased, rather than decreased, social conflict (Waters 2006) leading some researchers to argue that there is a “need for much more complex and empirical approaches for doing conservation with local communities” (Brockington et al. 2008, p. 110). Brockington and his colleagues go on to suggest that a “more open-ended, empirical approach is much more likely to help us find approaches that are effective, equitable and more in line with local needs and values” (p. 111). In this research synopsis, we describe one such open-ended empirical approach to community-based natural resource management, developed over an 8-year initiative in a rainforest community in Amazonas State, Brazil. The conceptual basis of the approach, dubbed sustainable open systems/SOS (Ribeiro and Fabre 2003), was to gather detailed information on the cosmography (environmental knowledge, ideologies, and identities collectively developed and historically located) that the community uses to establish and to maintain its territory, and use this as the basis for sustainable management and formal resource use agreements. The term ‘open systems’ was chosen to reflect the inevitable flux of people and resources in and out of the management area or system. To better illustrate the SOS approach we present data from one of our case studies that took place in the Manacapuru district of Amazonas State, Brazil. The inhabitants of this district are broadly representative of the non-tribal peoples of Amazonia, being composed of individuals of mixed descent with different degrees of historical and cultural affiliation with the surrounding rainforest. Most families engage in productive activities that are common in inhabitants of the Amazon floodplain such as fishing, collecting and small scale agriculture (Furtado 1993a, 1993b). An eight year project was initiated in 1998 by the multidisciplinary PYRA research group (Integrated Program of Aquatic Resources and Floodplains) with the aim of designing a co-management system for local fisheries that was clearly aligned with local customs and practices and which would provide a robust framework for the development of sustainable practices.

Seleção das estruturas calcificadas para determinação da idade da piracatinga Calophysus macropterus Lichtenstein (Siluriformes: Pimelodidae) na Amazônia Central, Brasil

The goal of this study was to identify the best calcified structure for determination of the age of the piracatinga (Calophysus macropterus). A total of 440 specimens from commercial samples and experimental fishing in the Solimoes River. Were used for analysis: Opercula, otoliths, and vertebrae were analyzed from a sub sample (n=130). Two clarification techniques were used for visualization of growth rings in the otoliths and four coloration techniques for vertebrae. The otoliths were not translucent and it was very difficult to see the growth rings. The vertebrae were the best calcified structure because the radius of the vertebrae and the length of fish had clear significant linear relationship (r= 0.91; P<0.05) and a clear visualization of the growth rings. Among the techniques used for examining vertebrae of the teleostean fishes, the chemical decalcification, hyper-oxidation technique, was the best to observe the growth rings in the vertebrae. The seasonal rings were validated using relative marginal incremental analysis. Two annual rings are formed in the vertebrae of Calophysus macropterus, being the first during low water (August) and the second during high water season (January). On the vertebrae, a maximum of seven rings were observed.

Estuarization increases functional diversity of demersal fish assemblages in tropical coastal ecosystems

This study assessed the influence of the seasonal fluctuation of abiotic conditions (wet v. dry season) on the functional diversity (FD) of tropical coastal fish assemblages. Sampling was carried out in three regions of north-east Brazil with contrasting coastlines (influenced by reef, lagoon and estuary). In each region, fishes were sampled from three depth strata (10, 20 and 30 m) and FD was estimated using an index based on key phenotypic and behavioural characteristics. All three regions had higher FD in the wet season at shallower depths, indicating the coexistence of species with low functional redundancy in sites subject to seasonal flushing of fresh water. Deeper sites had lower FD than shallower sites, although this difference was less pronounced for region 3, which is strongly affected by its proximity to the São Francisco estuary. The results broadly support the hypothesis that alterations in abiotic conditions in the wet season allow estuarine-adapted fishes with a different suite of functional traits to invade shallow coastal regions.

Uso e gestão do território em áreas de livre acesso no Amazonas, Brasil

The traditional communities of the Amazon floodplain occupy a large variety of seasonal environments and have adapted to the variations determined by the flood pulse, which is reflected in the development of their resource managment strategies. In this work the territoriality of these communities was evaluated by observing the cost-benefit relationship for fisheries, forests and agricultural exploration to social and environmental conflicts originating from the explotation of natural resources of common property in areas of open access. Interviews were conducted between August of 2003 and November of 2004, with the head of family in 50% of each community studied, on the coat of Canabouca, district of Manacapuru. The variables used to evaluate territoriality were: production, revenue and distance traveled. The areas of exploitation were analyzed using Global Information System (GIS). The results indicated that fishing activities generate conflicts and territoriality, which is the product of the interaction between distribution, avaliability and productivity of fishing areas and the political organization of the communities, that is reflected in the cost-benefit relationship.