Vandick da Silva Batista

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.

Characterization of the commercial fish production landed at Manaus, Amazonas state, Brazil

The present work aims to update a series of information about the regional fishing production, by presenting and characterizing the contribution of the different sub-systems of the Amazon basin to the catch landed at the main fishing market of Manaus, Brazil, from 1994 to 1996. Collectors specifically hired for this function registered key information on the fisheries. Thirty nine types or groups of fish were found in the fishing production landed. Jaraqui (Semaprochilodus spp.), curimata (Prochilodus nigricans), pacu (Myleinae), matrincha (Brycon cephalus), sardine (Triportheus spp.), aracu (Anostomidae) and tambaqui (Colossoma macropomum) were the most important items during three consecutive years. In 1994 these items summed up 91.6% of the total production; in 1995 and 1996 these values were, respectively, 85.3% and 86.4% of the total production. Tambaqui landed decreased remarkably during the period 1976-1996. There was a strong seasonal component in the production of the main species; jaraqui and matrincha were mostly landed between April and June, while curimata, pacu, and sardine were mostly landed during the dry season. Other important items showed a strong inter-annual variation in their production. The fishing production landed came mostly from the sub-system of the Purus River (around 30% of the total production). The subsystem of the Medium-Solimoes contributed with an average of 15% and the sub-systems of the Madeira, Lower-Solimoes, Upper-Amazon and Jurua, together contributed with 11.5% of the total production landed. Finally, the remaining sub-systems contributed with only 7.6% of the production.

Determinação de idade e crescimento do mapará (Hypophthalmus marginatus) na Amazônia Central

O presente trabalho visa contribuir para a conservacao e manejo do mapara (Hypophthalmus marginatus), um importante recurso pesqueiro de exportacao do Amazonas para o qual e necessario conhecer informacoes essenciais de sua dinâmica de populacoes. Para contribuir a esta finalidade, o presente trabalho estabeleceu como objetivo identificar o par de otolito mais adequado para leitura de aneis etarios, determinar os parâmetros de crescimento do mapara (H. marginatus), Amazonia Central, Amazonas - Brasil. O trabalho foi efetuado atraves da analise de otolitos coletados no periodo de dezembro de 1996 a agosto de 1997. Os otolitos escolhidos foram os asteriscus, sendo a leitura efetuada em lupa estereoscopica com monitor acoplado. As marcas de crescimento foram validadas por meio da analise do incremento marginal relativo, sendo encontrado dois aneis/ano. Os valores estimados para os parâmetros no periodo foram L¥ = 52,63 cm; k = 0,555 ano; to = -0,029 e M = 0,552. O ciclo hidrologico e comportamento reprodutivo estao relacionados com a marcacao de aneis etarios.

Aspectos econômicos e operacionais das viagens da frota pesqueira de Manaus, Amazônia Central.

Fishery in the Amazon represents an important social, economic and cultural activity with yearly fish landings around 25 thousand tons in the fishing harbour of Manaus alone, with little socioeconomic evaluations that are fundamental for its management. The present paper sought to evaluate functional aspects of fishing operations from the economic point of view. Information was collected from 92 boats, between October of 1999 and June of 2000, through questionnaires given to boat owners or general managers of fishing expeditions. Small fishing boats presented mean operational cost of 45.2% of the gross income of fish sales. Medium and larger boats presented values of 42.0% and 47.8% costs, respectively, where fuel was the main expenditure.

Avaliação do desembarque pesqueiro efetuado em Manacapuru, Amazonas, Brasil

The fishing commercial activity in Central Amazonia is mainly addressed for Manaus, even so the characteristics of the fishing activities directed to other important urban centers in the region are also fundamental for the planning of the sector. In this context, the present work seeks to characterize the profile of the fishing production that lands in the city of Manacapuru, one of the main urban centers of Central Amazon. Fish landings were done from non-motorized canoes, motorized canoes, fishing ships and pleasure boats. The monthly average of landed fish was of 175,36 ± 39,50 ton in 2001 and of 172,13 ± 18,88 ton in 2002, not presenting significant difference among years (P>0,05). Of the 35 registered common species names, it is observed that curimata (Prochilodus nigricans), jaraquis (Semaprochilodus spp.), cubiu (Anodus spp.), mapara (Hypophthalmus spp.), and tambaqui (Colossoma macropomum) were the most important fish landed in 2001 and 2002, and piramutaba (Brachyplatystoma vaillantii) specifically in 2002. out of the seven sub-areas visited by the fishing fleet, Lower Solimoes and Purus river stand out.

Caracterização da frota pesqueira de Parintins, Itacoatiara e Manacapuru, Estado do Amazonas

The physical characteristics of the Manacapuru, Itacoatiara and Parintins fishing fleets were analyzed and compared with the Manaus fleet, using data collected from the landing ports along with secondary data obtained from federal institutions and the Amazonas Association of Fishermen. It was found that the size of individual canoes varied according to the center analyzed, with the larger ones found in Manacapuru and Itacoatiara. The size of the Parintins fishing vessels was significantly smaller than those in Manaus, Manacapuru and Itacoatiara. Yanmar engines predominated in all municipal districts. There was a linear relationship between the engine power and size of the vessel. The oldest vessels were found in the Manacapuru fleet, followed by the fleet of Itacoatiara. The Parintins and Manaus fleets were the newest, although the latter had the greatest age range. Fishing boats tend usually to have 5 to 6 fishermen and individual canoes 2 to 3. While fishing vessels working down river make longer trips, no difference in trip length was found for individual canoes in the different municipalities analyzed. Parintins fishing boats produced less fish than those of Manacapuru and Itacoatiara. Yield per fisherman during the height of the fishing season was greater for fishing boats than for individual canoes. Results indicate that the Parintins fleet differs from the others and that the individual canoe fishery must be considered separately from that of the fishing boats with regards to fishery management policy and actions.

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.

Dinâmica populacional da matrinxã Brycon amazonicus (Characidae) na Amazônia Central

The matrinxa, Brycon amazonicus (Spix & Agassiz, 1829) is one of the most important fishery resources of the Amazonas state. Its population dynamics in Central Amazon was analyzed based on total landing and biometry data registered in the main landing port of Manaus, between 1994 and 2002. Growth and mortality rates were estimated separately for the rivers Purus, Madeira and Solimoes. Differences in size structure and growth curves suggest that different population units exist among these rivers, requiring individualized evaluation and fisheries management strategies. The analysis of the yield per recruit does not indicate overexploitation. However, the highest relative exploitation rate was observed in the Madeira river. The suggested management strategies are related to restrictions to the fishery in the main fishing grounds during the migratory dispersal period, instead of restrictions during reproductive periods.

Caracterização do uso de malhadeiras pela frota pesqueira que desembarca em Manaus e Manacapuru, Amazonas

The gillnet is frequently used in Amazon commercial and artisanal fishing. The present study aims to verify characteristics of the gill-nets of gillnets found in various Central Amazon subsystems, their use, and compliance with related legal norms. Daily Interviews were made from 1994 to 2004 in Manaus, and from 2001 to 2004 in Manacapuru. The results indicated that the gillnet was responsible for about 14% of the yield landed in Manaus, with a tendency to diminish, but a stable 24,5% in Manacapuru. Modal mesh sizes were 50-60mm in Manaus, but ranged from 20 to 90mm in Manacapuru, and the modal length was 100 m for both. In Manaus this size accounted for about 90% of all gillnets recorded, but in Manacapuru it was less than 50%. The Manaus fleet preferred to exploit the region of Purus (47,8%), while the Manacapuru fleet preferred the Low Solimoes (94,3%). The composition of gillnet catches varied during the interviewed years, but 70% of the total was usually made up of tambaqui, aruana, tucunare, curimata, and pirapitinga. Most mesh sizes and lengths were illegal. We concluded that the legal norms for gillnet use should be adapted to fishery characteristics, but also to the socioeconomic and cultural reality of the Amazon.

Age and growth of the daggernose shark, Isogomphodon oxyrhynchus, from northern Brazil

Age and growth of the daggernose shark, Isogomphodon oxyrhynchus, from northern Brazil were deter- mined from 105 vertebral sections stained with alizarin red-S representing 46 males, 52 females and 7 specimens of unknown sex (58.4 to 141 cm-TL) and verified with length-frequency analysis of 1135 specimens (632 females and 503 males, 58-160 cm ). Marginal increments did not show significant differences throughout the year, and it was assumed that one band is formed annually. Different tests provided varying results for growth curve comparisons between sexes; the curves were similar, despite biological differences. von Bertalanffy growth parameters estimated from back-calculated mean lengths, observed mean lengths-at-age and length-frequency analysis were of the same magnitude. Parameters generated from observed length-at-age were chosen for describing growth for the species: L∞ 171.4 cm, k 0.12 year -1 and t0 -2.612 years. The largest female aged from vertebrae was 12 years old, whereas the largest male was aged at 7 years. Neonates, ~42.3 cm, showed one band in the vertebrae, formed at birth, or soon thereafter. Males are mature at 103 cm or 5-6 years and females at 115 cm or 6-7 years. Resumo. A idade e o crescimento do cacao quati, Isogomphodon oxyrhynchus, do norte do Brasil foi determinada usando 105 vertebras seccionadas e coradas com alizarina vermelha-S de 46 machos, 52 femeas e 7 exemplares de sexo indeterminado (58,4-141 cm-CT). Analise de distribuicao de frequencia de comprimentos de 1135 individuos (632 femeas e 503 machos, 58-160 cm) foi utilizada como metodo de verificacao. Os incrementos marginais nao mostraram diferencas significativas ao longo do ano, assumindo-se que uma banda e formada anualmente. Com diferentes testes, usados para comparar curvas de crescimento entre os sexos, obteve-se resultados conflitantes; o crescimento foi considerado identico entre os sexos, apesar das diferencas biologicas entre machos e femeas. Os parâmetros de von Bertalanffy estimados do retrocalculo, comprimentos medios observados e da analise de compri- mentos foram semelhantes, tendo sido escolhidos para descrever o crescimento da especie: L∞ 171,4 cm; k 0,12 year -1 e t0 -2,612 years. A maior femea cuja idade foi estimada pelas vertebras tinha 12 anos enquanto o maior macho tinha 7 anos. Recem-nascidos de 42,3 cm apresentavam uma banda nas vertebras, formada ao nascer, ou logo depois do nascimento. Machos estao maduros em 103 cm ou 5-6 anos e femeas em 115 cm ou 6-7 anos.