Navegando por Autor "ISAAC, Victoria Judith"

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Acesso aberto (Open Access)
Biologia e estrutura populacional das espécies da família sciaenidae (Pisces : Perciformes), no estuário do rio Caetê município de Bragança, Pará-Brasil
(Universidade Federal do Pará, 1999-03) CAMARGO-ZORRO, Mauricio; ISAAC, Victoria Judith; http://lattes.cnpq.br/3696530797888724
This study aimed to assess the average biomass and spatial and temporal distribution of the family Sciaenidae fishes in the estuary of the Caeté River, northern of Brazil, with special reference to the species Stellifer rastrifer, Stellifer naso, Macrodon ancylodon and Cynoscion microlepidotus. Age at first sexual maturity (L50), spawning season, the length-weight relationships, food diet, population consumption by biomass (Q/B), population structure and dynamics were estimated. 6 Bimonthly samples were taken in the estuarine area of the Caeté River, from October 1996 to August 1997. The average biomass of the family Sciaenidae was 0,840g/m². The spatial distribution in the system was related to spawning and recruitment. Juveniles of S. rastrifer, S. naso e M. ancylodon occurred inside some areas in the estuary, although larger individuals were abundant outside where salinity is higher. The L50 values were 10cm, 10,7cm e 21,5cm respectively. Two spawning periods in a year were found, which determine the recruitment of two cohorts, with different growth parameters. The length-weight relations were allometric and no differences were found by sex. An ontogenetic change was found in the diet composition of these species; young prey zooplancton and adults feed predominantly on larval stages of decapodes and poliquetes, and juveniles of fishes. Diet overlaps changed during the ontogenic development of each species. The relation Q/B indicated that S. rastrifer and S. naso consume more food in relation to the body size, in opposite to the larger species like M. ancylodon and C. microlepidotus. The fishes of the Caeté River presented higher growth and low longevity when compared to the same species inhabit the higher latitudes.
Acesso aberto (Open Access)
Biologia reprodutiva e dinâmica populacional de Hypancistrus zebra Isbrücker & Nijssen, 1991 (Siluriformes, Loricariidae), no rio Xingu, Amazônia brasileira
(Universidade Federal do Pará, 2011-05-25) ROMAN, Ana Paula Oliveira; ROCHA, Rossineide Martins da; http://lattes.cnpq.br/4371300451793081; ISAAC, Victoria Judith; http://lattes.cnpq.br/3696530797888724
Hypancistrus zebra is a specie used with ornamental purposes, endemic and rare in the Middle - Lower Rio Xingu, which has strong demand from the international ornamental fish market, which created a strong pressure of exploitation associated with this species. H.zebra is included on the list of Brazilian fauna threatened with extinction and their capture is prohibited. It is known that even prohibited, it continues to be captured and exported illegally, together with the construction of this hydroelectric Belo Monte in his patch of distribution, which threatens their geographical distribution and lack of information on its biology and ecology make it difficult planning actions for this species. So, if this work aimed to study aspects of reproductive biology and population dynamics to contribute to conservation measures for this species. Specimens of H. zebra were taken monthly from March 2009 to February 2010, by diving with a compressor, on the Xingu River, between the location of the weevil and Rita village of Belo Monte. The captured individuals were weighed and measured (total weight and total length). The gonads were removed and immediately fixed in Bouin solution. This was followed by routine histological techniques and the slides were stained with hematoxylin-eosin (HE). The stages of gonadal maturation were described based on the presence of germ cells at different stages of development. Through the length frequency data, estimates of population parameters such as growth models, recruitment, mortality, yield per recruit and size of first gonadal maturity. The species showed a seasonal spawning peaks between the two transition seasons of drought and flood (and vice versa) of the river, and two periods of recruitment, with different growth rates. It was estimated that the species has a lifespan of five years, and is at the limit of maximum sustainable yield, which is characterized as a dangerous situation for the species, because any increase in effort will compromise the stock and it is not known impacts that occur as a result of changes in their habitat caused by dam construction.
Acesso aberto (Open Access)
Composição, abundância e pesca da ictiofauna como indicadores do estado de conservação de dois lagos de várzea no baixo Rio Amazonas (Brasil)
(Universidade Federal do Pará, 2010) ALMEIDA, Morgana Carvalho de; ISAAC, Victoria Judith; http://lattes.cnpq.br/3696530797888724
The Amazon floodplain has a rich biodiversity and its characteristics influence the economically and ecologically important natural aquatic resources for the people. On the basis of these information, the objective of this research was to characterize the composition and abundance of ichthyofauna in two floodplain lakes in the Santarem region, and to understand the use I buy fishers in the Piracãoera and Campos fishing communities, in the Urucurituba region, and Barreira and Correio communities in the Tapará region. Samples were taken in the Aramanaí and Curiquara lakes considering the four hydrological periods (rising, flood, low, dry) for the period between July of 2006 and April of 2007. For the fish sampling were used set gillnets batteries. To collect data on catches of fishermen, forms were used that contained information about the characteristics of the fisheries. We caught 10,146 fish, which were distributed in 156 species, 27 families and 8 orders. The most abundant families in number of individuals were Sciaenidae and Loricariidae. In Aramanaí Lake, the Loricaria sp, was the species with the highest CPUAn with 0.02 individuals per m². hour. In terms of CPUAp featured species Potamotrygon motoro, with 0.13 g.m ². hour and Pterygoplichthys pardalis with 0.11 g. m². hour. In Curiquara Lake, the main catch in number of individuals was represented by the Pachypops fourcroi with 0,001 individuals per m² of gillnet. Curiquara and Aramanaí lakes 9 trophic guilds were identified and for both lakes fish piscivores and detritivores showed the largest catch by weight. The average length of individuals caught in the lakes was 20.27 ± 7.53 cm. The highest mean length of individuals was in the flood and lower in the low period. When fishing is practiced by fishermen used a variety of fishing gear devices highlighting the gill netting. The use of gear depends on the environment exploited, target species, and in addition to the season, and there may be combinations of more than one gear during the catch. The average yield of the fisheries in the two regions was 10 kg.fishermen.dia-1. In Urucurituba region the CPUE average was 16kg.fishermen.dia-1, in Tapará was 4.5 kg.fishermen.dia-1. The Urucurituba’s fishermen showed the higher catch volume and fish marketing. These communities are partially fulfilling the rules of the fisheries agreements.
Acesso aberto (Open Access)
A comunidade ictica e suas interrelacões tróficas como indicadores de integridade biológica na área de influencia do projeto hidrelétrico Belo Monte-Rio Xingu, PA
(Universidade Federal do Pará, 2004-04) CAMARGO-ZORRO, Mauricio; ISAAC, Victoria Judith; http://lattes.cnpq.br/3696530797888724
This study presents applied methodologies to better understand the dynamics of mechanisms characterizing a portion of the Xingu River, with respect to fish communities living in that environment. Through the study of the ichthyofauna it is aimed to verify various environmental standard patterns, in order to assess the current conservation state of a part of the Xingu River. Based on surveys of the local ichthyofauna conducted over seasonal variations, analyses were conducted at the specieS, population and trophic guild levels. With regards to the ecological population level, study of biological parameters such as individual growth rates, asymptotic body length, mortality rates and size at first maturity were good indicators for a better understanding of the life history of those fish groups. Therefore a trend was observed in which species of relatively small body size to followed a "r" type strategy, whilw species of larger body sizes would follow the "k" strategy tactics. From a functional point of view, it was verified that guild community structure is not only a good indicator of convergence patterns to similar ecosystems as like the Xingu River studied stretch, but also a tool to assess its conservation status. A steady- state ecosystem model for the medium Xingu River sector indicated that it is a system highly instable, and simultaneusly look like a mature seasonal system. An apparent seasonal restriction of food availability observed in the studied river section could imply optimum use efficiency and transfer of the trophic resources. A biogeographic study was undertaken based on species occurrence in order to conceptualise the River stretch comprised between the confluences of the Iriri and Xingu Rivers up to the vicinity of of the village Senador José Porfirio, in the Xingu basin. By means of this analysis, it was possible to demonstrate that the medium upstream of waterfalls) and lower (downstream) courses of the Xingu River are parts of two endemic areas. The low affinity of species composition observed in these two sectors is attributed to geographic variations in the landscape. Therefore, the boundaries of the waterfalls around the village of Belomonte and the influence of the Amazon River in the lower Xingu course could trigger differences in ichthyofaunal composition and species abundance when compared to the medium course of that river. Finally, the importance of maintaining all hydrologic connectivity is pointed out in order to maintan the unity of the system, from the headwaters to the mouth. Impacts on environmental processes and fish populations in the medium course of the Xingu River as a result of the eventual construction of the Belemonte hydroelectric dam are discussed.
Acesso aberto (Open Access)
A comunidade zooplanctônica em um canal de maré no estuário do rio Caeté, Bragança (Pará, Brasil)
(Universidade Federal do Pará, 1999-04-30) PERES, Ariadne da Costa; ISAAC, Victoria Judith; http://lattes.cnpq.br/3696530797888724
There are few studies mede about zooplankton in estuaries of Bragança region, Pará State. This work was done in a tidal creek, named Furo do Chato, next to Ajuruteua, Bragança's district which is part of Pará State seashore and aimed to study lhe zooplankton qualitative and quantitative composition, as well as lhe sazonal variations and the environmental effect variables of the zooplankton composition. From August/96 to January/97 every three weeks for a period of 24 hours, zooplankton samples were taken every two hours. Furo do Chato is a tida l creek with strong coaste! influence. Hence the great majority of lhe zooplankton categories found are from coaste! water. Besides holoplankton and meroplankton components, lhe zooplankton samples from Furo do Chato has a strong bentonic component. Ten phyla were identified: Protozoa, Mollusca, Chordata, Annelida, Cnidaria, Arthropoda, Urochodata, Chaetognatha, Nematoda e Bryozoa. The Copepoda class had higher representative, even for density, biomass as well as occurrence frequency in the community. The most abundant and frequent Categories (>40%) were Pseudodiaptomus marshi, Acartia lilljeborgi, Acartia tansa, Harpacticoida, Sagitta sp., Oikopleura dioica, Cnidaria, Isopoda, crabs zoeas, shrimps post-larvae and fish larvae. The average densities and biomass were low (1,07 indiv./m³ e 16,43 mg/m³). The zooplankton community is more abundant in the transition months than in the dry period. The highest abundances took place at night and during the spring lides. Tide, salinity and different moon phases did not infiuence in the zooplankton as a whole, but only in some categories isolated.
Acesso aberto (Open Access)
Diagnóstico da pesca no litoral paraense
(Universidade Federal do Pará, 2004-02) SILVA, Bianca Bentes da; ISAAC, Victoria Judith; http://lattes.cnpq.br/3696530797888724
Acesso aberto (Open Access)
Diet and niche breadth and overlap in fish communities within the area affected by an Amazonian reservoir (Amapá, Brazil)
(2014-03) OLIVEIRA, Júlio Cesár Sá de; ANGELINI, Ronaldo; ISAAC, Victoria Judith
We investigated the niche breadth and overlap of the fish species occurring in four environments affected by the Coaracy Nunes reservoir, in the Amapá Brazilian State. Seasonal samples of fishes were taken using a standard configuration of gillnets, as well as dragnets, lines, and cast¬nets. Five hundred and forty stomach contents, representing 47 fish species were analyzed and quantified. Niche breadth and overlap were estimated using indexes of Levins and Pianka, respectively, while interspecific competition was evaluated using a null model (RA3). ANOVA and the Kruskal¬Wallis test were used, respectively, to evaluate differences in niche breadth and overlap between areas. The data indicate that the majority of the fish species belong to the piscivore, omnivore, and detritivore guilds. These species have likely colonized the environments due to the availability of suitable feeding resources, and the favorable physical conditions created by the river damming. Overall, few species have ample niches, but most of them are highly specialized. Resources seasonal variation had little effect on the feeding behavior of most species in the study areas. The null models indicated that competition was not a factor determining on community structure.
Acesso aberto (Open Access)
Diversidade e variabilidade espaço-temporal da ictiofauna da região estuarina do rio Curuçá município de Curuçá, Pará Brasil
(Universidade Federal do Pará, 2006) HERCOS, Alexandre Pucci; ISAAC, Victoria Judith; http://lattes.cnpq.br/3696530797888724
The study of estuarine fish communities has called researchers’ attention due to the fact that these ecosystems present a great variety and abundance of fish, many of which have commercial importance. Such studies have become fundamental in the evaluation of fish stocks, and also contributed to the conservation of coastal and estuarine environments. Rio Curuçá’s estuary is located at the coastline in the northern part of the state of Para, although fishing is the main economic activity in towns of the region, there are a few studies on local ictiofauna. The main objective of this study was to characterize the demersal ictiofauna of the main channels in the Curuçá River estuary, identifying annual and spatial variations in the composition, density and biomass of ictiofauna, as well as non-biotic factors that influence these variations. In order to this, data collection trips were carried out once every two months, using trawl net, in two of the main estuary channels. At the end of the study, 18.989 individuals of 73 species were captured. Ophichthus cylindroideus, Hippocampus reidi, Sygnathus pelagicus and Butis koilomatodon had not yet been registered in the state’s north coastline. Sciaenidae, Engraulidae and Ariidae families were the most representative in number of species, density and biomass. 20 species, classified as estuarine, were majority, and presented leading densities and biomass in all months and capture stations. Average density (0,12 ind/m²) was significantly greater during the rainy season, but biomass (1,11 g/m²) did not present significant changes during the months of capture. The Curuçá area has presented greater richness of species, density and biomass. This difference is related mainly to a greater heterogeneity of substrat in the area, and thus a greater availability of microhabitats. Physical and chemical composition of water was homogeneous in capture stations, and had little influence on the spatial distribution of ictiofauna. The registration of new species for the region enforces the importance of other studies for a greater comprehension of local ictiofauna, which is an important economic resource to the local human population.
Acesso aberto (Open Access)
Ecologia, pesca e dinâmica populacional do camarão-da-Amazônia - Macrobrachium amazonicum (Heller, 1862) (Decapoda:Palaemonidae) – capturado na região das ilhas de Belém - Pará - Brasil
(Universidade Federal do Pará, 2011) SILVA, Bianca Bentes da; MARTINELLI-LEMOS, Jussara Moretto; http://lattes.cnpq.br/5264841936875017; ISAAC, Victoria Judith; http://lattes.cnpq.br/3696530797888724
In monthly biological samples of M. amazonicum in Guajará Bay and Mosqueiro island, were studied reproduction, density, morphometric relationships and population dynamics. Two other sample designs was realized in two perennial the same estuary. Results indicate differences in capture of this species using different bait of meal, but is solely on the abundance and population structure does not change. The species is most abundant in the dry season, supporting the idea higher catchability of fishery resources. In Combu island was found species with larger sizes. Females are significantly larger and heavier than males, indicating the differentiation in metabolism due to reproduction. Sex ratio of males is higher in smaller size classes, which may indicate an increase in predation on smaller sizes of males due to their behavior more aggressive than the females or males simply because they reach lengths larger than females are more heavily preyed upon by fishing, with the recruitment of only the smaller males. First maturation length for both sexes resulted in 11.5 mm – carapace length - (11.5 mm in males and 11.2 mm in females). Reproduction in M. amazonicum is continuous or periodic a gradual increase during the months from October to March. The most common sites housed, as inner regions of tidal channels or holes (common in Amazon estuary) sites are preferentially sought by mature females for spawning and juvenile growth. Von Bertalanffy growth parameters obtained were very similar between the sexes, where L ∞ = 44.8 mm and K = 0.35 for males and L ∞ = 46.5 and K = 0.31 for females. Mortality and exploitation obtained was in maximum sustainability and the management should be treated fairly care. In this situation, any increase in effort may result a state of over-exploitation of growth. Allied to near commitment of the stocks of M. amazonicum of the socio economic fishing is no different from other systems of coastal fishery Para: poor education, poor performance of professional associations, chain productive complex and that its main underprivileged. We suggest the statistical monitoring of production, the delineation of the minimum capture length in 4.5cm; suppression of fishing with matapis in headwater areas of creeks and tidal channels, a census of users and the use of models bioeconomic that include major aspects of its biological and productive chain.
Acesso aberto (Open Access)
Efeito de características ambientais no uso dos canais-de-maré por três espécies de peixes bentófagos durante o período transição-seca no estuário de Curuçá (Pará-Brasil)
(Universidade Federal do Pará, 2009-08-10) ALMEIDA, José Bruno Araújo de; GIARRIZZO, Tommaso; http://lattes.cnpq.br/5889416127858884; ISAAC, Victoria Judith; http://lattes.cnpq.br/3696530797888724
The Curuçá estuary is part of a Conservation Unit (RESEX Great Mother of Curuçá) since 2002 and has as main water courses the Curuçá River and Muriá bore. This study aimed to analyze the effect of environmental characteristics in the use of the creek on the benthophagous species Colomesus psittacus, Sciades herzbergii and Genyatremus luteus. The analysis involved the relationship of environmental data (salinity, submergence area and tree cover) and biotic data from the three species studied (density, biomass, feeding intensity and distribution of total length). The first expedition took place in July 2008 to collect the fish fauna and the second in October 2008 to conduct the tree inventory, and each campaign lasted for three days. For all the estuary of Curuçá, more precisely, along the Curuçá River and Muriá bore were allotted a total of six study sites, where within each site were sampled two creeks, making a total of twelve creeks sampled. The species C. psittacus, S. herzbergii and G. luteus were among the five most abundant and occurred in all sites, except for S. herzbergii, which was captured only in five of the six sites. The three species showed, among sites, highly significant differences for changes in their average density, biomass, index of fullness and length, except for G. luteus which did not show statistical differences in their average total length. All variations of the average environmental characteristics related to tree cover (density, height and diameter), as well as, the area of flood creek showed significant differences between sites. This study has showed: the influence of salinity gradient in the distribution of species within the estuary; spatial relations between the flooded area and availability of food resources, where the creek with larger flooded area were more conducive to forage fish fauna benthophagous; likely, there is a better yield when feeding species benthophagous occurs in creek surrounded by vegetation developed.
Acesso aberto (Open Access)
Effects of plant cover on the macrofauna of Spartina marshes in northern Brazil
(2009-12) BRAGA, Cesar França; BEASLEY, Colin Robert; ISAAC, Victoria Judith
Data on macrofauna density and diversity, and the height and density of Spartina brasiliensis, were obtained from salt marsh beds of a tropical estuary in northern Brazil. Sampling was carried out at four distinct times of the year, during the wet and dry seasons and in the transition periods between these. Sampling was also carried out in salt marshes of three size classes, small, medium and large. Variables were analyzed in relation to time of year and salt marsh size class. Overall, 46 taxa were found, with polychaetes, isopods and the gastropod Neritina virginea dominating the fauna. Macrofauna density and diversity were positively correlated with culm density, indicating a possible role in protection from predation. All the three variables were higher during the transitional periods between the wet and dry seasons and seasonal changes in rainfall, salinity and light availability may influence mortality, food availability and settlement of the macrofauna. There was no effect of salt marsh size on either the macrofauna or the vegetation.
Acesso aberto (Open Access)
Estrutura populacional, uso de ambientes e crescimento corporal de Rhinoclemmys punctularia punctularia (DAUDIN, 1801), na Ilha de Algodoal/Maiandeua, Maracanã, Pará, Brasil
(Universidade Federal do Pará, 2010-02-26) FIGUEIREDO, Manoela Wariss; PEZZUTI, Juarez Carlos Brito; http://lattes.cnpq.br/3852277891994862; ISAAC, Victoria Judith; http://lattes.cnpq.br/3696530797888724
For Rhinoclemmys punctularia punctularia (Daudin, 1801), until this study, there were no further studies that focused on their ecology in natural environment. In general, the existing works are based on few records at different locations in range of the species and data from animals in captivity, such reports have described the species as a generalist in relation to their feeding and the use of environments. This study aimed to evaluate the use of environments, the population structure and estimate the constant growth of the Rhinoclemmys punctularia punctularia in Island of Algodoal/Maiandeua, which is an environmental protection area (APA). As methodology were conducted experimental fishing in different environments of the APA of Algodoal/Maiandeua, between the years 2008 and 2009. Of the sampled specimens were captured only environments without the influence of marine waters and abundant food resources, such as the fruits of Annona sp. and Chysobalanus sp.. Environments used by R. p. punctularia (flooded forest, temporary ponds and lagoons of the plain), the highest yields were found in lagoons of the plain, where there is a greater availability of fruits of Annona sp. and Chysobalanus sp in water bodies that the species occupies. The population of R. p. punctularia in Algodoal/Maiandeua is mainly composed of adults and is slightly skewed towards females (0.43 males). The average length of females is 195.42±18 mm (range 43-226 mm) (n=68) while the males is 167±12.7 mm (range 133-197mm) (n=64), the females being statistically larger than males (U=454.02; GL=132, p=0.0001, n=132). In both sexes there was a significantly negative relationship between growth rate and length of the carapace. The model of von Bertallanfy was an estimated value of k=0.19 year-1 for males and k=0.16 year-1 for females, since the values of L∞ were 207.36 mm and 237.89 mm for males and females, respectively. When you reach the CRC 237 mm for females and 207 mm for males, the species reaches the age of about 33 years in both sexes.
Acesso aberto (Open Access)
Feeding ecology of juvenile dog snapper Lutjanus jocu (Bloch and Shneider, 1801) (Lutjanidae) in intertidal mangrove creeks in Curuçá estuary (Northern Brazil)
(2009-12) MONTEIRO, Dijane Pantoja; GIARRIZZO, Tommaso; ISAAC, Victoria Judith
The diet and feeding ecology of juvenile dog snapper (Lutjanus jocu) were investigated in 92 specimens collected in four intertidal mangrove creeks of Curuçá estuary, Northern Brazil, between September 2003 and July 2004. No significant differences in total length were found between the sampling months. Feeding intensity was high as indicated by high stomach fullness index and low vacuity index. The most important prey was Penaeidae, followed by Grapsidae and Porcellanidae. The diet of juvenile dog snapper showed clear seasonal differences. Specimens from dry season (September and November) and dry / wet season transition (January), were specialists feeding exclusively on Penaeidae. However, the specimens from wet season (March and May) and wet /dry season transition (July) that consumed mainly Grapsidae, Penaeidae and Porcellanidae were generalist. These seasonal changes in diet could be related to variations in food availability.
Acesso aberto (Open Access)
Food categories reconstruction and feeding consumption estimates for the Sciaenid Macrodon ancylodon (Bloch & Schneider), and the congeneric fishes Stellifer rastrifer (Jordan) and Stellifer naso (Jordan) (Pisces, Perciformes) in the Caeté Estuary, Northern Coast of Brazil
(2004-03) CAMARGO-ZORRO, Mauricio; ISAAC, Victoria Judith
A quantitative method to estimate fish feeding consumption and energy intake from different food categories through the reconstruction of ingested preys based on hard not digestible body structures is presented. In order to establish the equations of the functional relationships between preys weight and body structures, stomachs of 1.086 specimens of Macrodon ancylodon (Bloch & Schneider, 1801), Stellifer rastrifer (Jordan, 1889), and Stellifer naso (Jordan, 1889) fish species were dissected. Consequently, preys reconstruction enabled a quantitative evaluation of food categories consumption. Results indicate a marked difference in diet composition and energy requirements according to fish species ontogenetic development.
Acesso aberto (Open Access)
Multidisciplinary approach to identification of fishery production systems on the northern coast of Brazil
(2012-03) SILVA, Bianca Bentes da; ISAAC, Victoria Judith; ESPÍRITO SANTO, Roberto Vilhena do; FRÉDOU, Thierry; ALMEIDA, Morgana Carvalho de; MOURÃO, Keila Renata Moreira; FRÉDOU, Flávia Lucena
Artisanal fishing on the northern coast of Brazil is characterized by a set of different fishery modalities. Using a multidisciplinary approach, 20 fishery production systems were identified, with distinct characteristics regarding technology and purpose. The characteristics of each system were classified into five dimensions (ecological, economic, social, technological and political). Multidimensional scaling revealed that some of these 20 systems have greater similarities. Thus, a total of 10 groups were identified.
Acesso aberto (Open Access)
Reproductive biology and spatio-temporal distribution of Stellifer rastrifer, Stellifer naso and Macrodon ancylodon (Sciaenidae) in the Caeté estuary, northern Brazil
(2005-06) CAMARGO-ZORRO, Mauricio; ISAAC, Victoria Judith
This study analyses the spatial and temporal distribution of the dominant Sciaenids in the Caeté estuary on the northern coast of Brazil. Samples were taken by otter trawls in four areas of the Caeté estuary between October 1996 and August 1997 six bimonthly. Stellifer rastrifer, Stellifer naso and Macrododon ancylodon presented the highest biomass out of eleven species of Sciaenidae caught. Minimum and mean length at first maturity were calculated and the main spawning periods determined. Changes in the spatio-temporal distribution of the three species were related to seasonal changes in estuarine salinity and spawning pulses. Larvae and juveniles of S. rastrifer, S. naso and M. ancylodon were found in the inner estuary while larger specimens were more abundant in the outer estuary with higher salinities. M. ancylodon spawned from October to February and rested from April to August whereas S. rastrifer and S. naso spawned throughout the year, though with two peaks, in October-December and June.
Acesso aberto (Open Access)
Spatial distribution of the amazon river prawn Macrobrachium Amazonicum (Heller, 1862) (Decapoda, Caridea, Palaemonidae) in two perennial creeks of an estuary on the northern coast of Brazil (Guajará Bay, Belém, Pará)
(2011-11) SILVA, Bianca Bentes da; MARTINELLI-LEMOS, Jussara Moretto; SILVA, Leiliane Souza da; CAVALCANTE, Danielle Viveiros; ALMEIDA, Morgana Carvalho de; ISAAC, Victoria Judith
Macrobrachium amazonicum is the most frequently consumed freshwater crustacean by river communities of the Amazon. Despite its relative abundance and vast knowledge on the species from data on cultivated specimens, little is known regarding its biology in the natural environment, especially its use of creeks that are strongly influenced by the tide. Specimens of Macrobrachium amazonicum were collected in September 2006 (dry season) and March 2007 (rainy season) from two perennial creeks of the Guajará Bay in the state of Pará (northern Brazil), using traps similar to the matapis used by local fishermen to identify the spatial distribution of the species. Shrimps of all sizes use the tidal creeks in both seasons, including for breeding purposes. The greatest abundance of the species occurred in headwater areas and in the dry season. It is suggested that abundant allochthonous organic matter and the preference for protected areas may explain the abundance and breeding activity of this species in the headwaters of the creeks.