Tambaqui (Colossoma macropomum) is the fish species most commonly raised in the Brazilian fish farms. The species is highly adaptable to captive conditions, and is both fast-growing and relatively fecund. In recent years, artificial breeding has produced hybrids with Characiform species, known as "Tambacu" and "Tambatinga". Identifying hybrids is a difficult process, given their morphological similarities with the parent species. This study presents an innovative molecular approach to the identification of hybrids based primarily on Multiplex PCR of a nuclear gene (α-Tropomyosin), which was tested on 93 specimens obtained from fish farms in northern Brazil. The sequencing of a 505-bp fragment of the Control Region (CR) permitted the identification of the maternal lineage of the specimen, all of which corresponded to C. macropomum. Unexpectedly, only two CR haplotype were found in 93 samples, a very low genetic diversity for the pisciculture of Tambaqui. Multiplex PCR identified 42 hybrids, in contrast with 23 identified by the supplier on the basis of external morphology. This innovative tool has considerable potential for the development of the Brazilian aquaculture, given the possibility of the systematic identification of the genetic traits of both fry-producing stocks, and the fry and juveniles raised in farms.

Oyster culture activity along the eastern Amazon mangrove coast in Pará state, Brazil, was evaluated using socio‐economic data to support its management and future development. Between 2013 and 2014, surveys were carried out in the region's seven oyster culture associations through interviews with the president of each association as well as with 56 members (72% of the total). Further data up to 2016 were obtained from annual reports of the Serviço Brasileiro de Apoio às Micro e Pequenas Empresas in Pará and the Instituto Brasileiro de Geografia e Estatística. Two associations stand out from the rest due to their larger on‐growing areas and total production in 2013. However, smaller associations are more efficient with higher production per unit area. Currently, oyster culture in Pará provides an alternative source of income for 80 families, where total production has increased from 8.25 tons in 2013 to 41.8 tons in 2016. Although associations have grown in number since 2006, along with increased capacity and production due to government assistance, in comparison with other regions of Brazil, they need to be better organized internally, including regular monitoring of growth, production and environmental variables, development of depuration facilities and improved distribution and presentation of products. Diversification of seed supply among different locations is desirable. There should also be less dependence on public funding and more partnerships with private enterprise, as well as active coparticipation in the development of legislation and public policies regulating both oyster culture and protection of natural oyster beds.

The PA-458 highway construction caused severe impact on mangrove Forest in the Ajuruteua peninsula, Bragança-PA, mainly at the Km 17. In order to better understand the effect of the highway construction on mangrove forest, it was undertaken a phytographic profile and a study on the structure of mangrove stands under three different levels of environmental destruction: Degraded Area (DA), Semi-Degraded Area (SDA), and Non-Degraded Area (NDA). Considering the three levels of destruction, mangrove stands comprise trees from 3 to 9 m of height, describing a gradient from the most impacted area till the non-impacted one, whereas values of mean DBH of these trees range from 4.2 to 10 cm. The trees dominance and density showed significant differences between the three different levels of impact (ANOVA, F=13.30; df=15; p

No abstract

Trace levels of three organophosphate insecticides (OPI) were detected in eight fish species from the region of Santarém, State of Pará, Brazil. Individual concentrations of OPI in fish ranged from less than the detection limit to 2,1 ppb. Mean concentrations of chlorpyrifos, malathion, and methyl-parathion were 0,3 ± 0,3, 0,1 ± 0,1, and 0,3 ± 0,3 ppb, respectively. Pellona flavipinnis, the largest and fattest piscivorous species analyzed, was the most contaminated. Since an inhabitant of this Amazonian region consumes 220 g of fish per day on average, ingested doses of chlorpyrifos, malathion, and methyl-parathion may reach up to 308, 220, and 462 ng·d-1, respectively. Compared to acceptable daily intakes (ADI), quantities of OPI absorbed via fish consumption on a daily basis are far below deleterious levels. We estimated that even considering the highest OPI contents detected, the average daily fish consumption of anadult of 60 kg would have to increase by ca. 1 950, 5 450, and 2 600 times to reach ADI of chlorpyrifos, malathion, and methyl-parathion, respectively. Neither fish diet nor fish lipid content enabled us to completely explain the interspecific differences observed.

Oyster culture has benefited traditional coastal communities along the Amazon macrotidal mangrove coast of Pará state in Brazil since 2006. Currently, seven oyster culture units in five municipalities are expanding production, but with no environmental monitoring, which is important for the control of the impacts of oyster culture on waters as well as for oyster management and conservation. Seasonal variation in environmental characteristics of the water was evaluated at all oyster culture units in Pará, from September to November 2013 (dry season) and February to April 2014 (wet season), to generate baseline data to evaluate future impacts and aid strategic planning, such as diversifying seed production. Salinity, dissolved oxygen, pH, oxidation-reduction potential, depth, temperature, and chlorophyll-a concentration were measured during flooding and ebbing tides, and compared between seasons and among culture units using uni- and multivariate statistics. All variables were significantly higher in the dry season, except depth, which was significantly greater in the wet season. Mean salinity, which varied from 2.4 to 46, explained most of the variation among culture units in relation to season, sampling date within each season and tidal state. However, dissolved oxygen, pH and depth were also important. Oyster culture units in Pará may be suitable for sustainable harvesting of seed/spat from the wild (lower salinity and pH), or for on-growing (higher salinity, higher pH, and greater depth). Seasonal variation is sufficient to allow both activities at most units at appropriate times of the year, which would help increase oyster production in Pará.

Resumo: O Mercado do Ver-o-Peso em Belém do Pará é um dos principais pontos de desembarque e comercialização de pescado do Brasil. Por ele desembarcam 35 mil toneladas de pescado por ano para o abastecimento da região metropolitana de Belém, envolvendo centenas de trabalhadores, com destaque para os balanceiros, agentes comissionados que comercializam a produção dos pescadores no local. O presente trabalho tem o intuito de realizar uma análise sociológica das transações econômicas na tentativa de explicar os mecanismos de funcionamento deste mercado a partir de pressupostos da Sociologia Econômica, como confiança, reciprocidade e cooperação. A metodologia inclui revisões bibliográficas e documentais, entrevistas semiestruturas, observação direta e registros audiovisuais. A análise de conteúdo foi feita a partir da tabulação e classificação dos dados. Os resultados apresentados demonstram a importância do balanceiro como coordenador logístico das transações comerciais realizadas no comércio atacadista de pescado fresco na Pedra do Ver-o-Peso. Espera-se, com este trabalho, fornecer aos acadêmicos e gestores públicos do setor um olhar mais preciso, a partir de uma perspectiva baseada nas motivações individuais e coletivas, nas relações estabelecidas entre os agentes e na construção social dos mercados, onde a palavra-chave é a imersão social (social embeddedness). Palavras-chaves:

The effects of smoking processes on the sensory and proximate components of two species of shrimp were evaluated. Sixty specimens of each species were distributed in a completely randomized design, with two treatments (T1 = hot smoking and T2 = liquid smoking), and fresh shrimps samples were used as control (T3). The sensory characteristics were evaluated using the 9 point hedonic scale and the acceptance index. The centesimal composition was evaluated based on 100 g from each treatment and the fresh samples. The data were submitted to one-way ANOVA and Tukey's test. The results of sensory analysis showed significant variations (p <0.05) for the attributes analyzed among the species, whereas among the smoking processes there was no significance (p >0,05). The acceptance rate was above 70% for amazonian prawn and 80% for white shrimp, regardless of the smoking method. The proximate analysis showed significant differences between the two smoking processes, hot and liquid, with moderet values of lipids, between 0.27% and 1.51%, and high protein values, of 24.61% 24.13%, for white shrimp and amazonian prawn, respectively. The smoking processes altered the sensory and chemical profile of the prawns, causing good acceptance and adequate nutritional constitution for smoked fish.