71 resultados para Peixes dulcícolas
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Knowledge of the environmental factors influence on the spatial-temporal variation of fishes is important to fisheries management and conservation. Thus, the aim of this work was to analyze the influence of the abiotical factors on the spatial-temporal distribution of Paralonchurus brasiliensis (Pisces, Sciaenidae) caught by-catch with the shrimp fishing of Ubatuba and Caraguatatuba regions, north coast of São Paulo State. The fishes were captured every month from January to December 2002. Samples were collected by otter trawl at 5, 10, 15, 20, 25, 30 and 35m depths. The temperatures (surface and bottom), salinities (surface and bottom), sediment features and organic matters were verified for each depth. During all period of the study 12.642 specimens of P. brasiliensis were captured at Ubatuba and 17.166 at Caraguatatuba, which totalized the biomass of 267 for the first and 339kg for the other region. The females outnumbered males in fish population. The greatest values of biomass and number of individuals were registered at the summer and autumn seasons, while the lowest values were observed at the winter and spring seasons. The greatest abundances were found from 15 to 25m depth. In this study, it was verified that P. brasiliensis is a coastal waters associate species. The spatialtemporal distribution of P. brasiliensis is affected by intrusion of SACW and depth for the coastal region and by depth and sediment in sheltered areas such as Caraguatatuba
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The Caatinga biome is rich in endemic fish species fauna. The present study the results of fish faunal surveys conducted in the hydrographic basin of Piranhas-Assu of the Brazilian Caatinga biome. The fish samples collected were distributed in four orders (Characiformes, Perciformes, Siluriformes and Synbranchiformes), 11 families (Characidae, Curimatidae, Auchenipteridae, Anostomidae, Prochilodontidae, Erythrinidae, Cichlidae, Sciaenidae, Heptapteridae, Loricariidae, Synbranchidae) and 22 species, of which 17 are endemic and five have been introduced from other basins. The order Characiformes was the most representative in number of species (46,35% ) followed by Perciformes (35,38%), Siluriformes (17,44%) and Synbranchiformes (0,5%). The Nile tilapia, Oreochomis niloticus, the only exotic species, was most expressive in number of individuals (24.92%) followed by the native species piau preto, Leporinus piau (18,77 %). Considering the relative frequency of occurrence of the 22 species, 13 were constant, five were accessory and four were occasional. This study investigated the reproductive ecology of an endemic fish black piau, Leporinus piau from the Marechal Dutra reservoir, Acari, Rio Grande do Norte. Samplings were done on a monthly basis from January to December 2009, and a total of 211 specimens were captured. The environmental parameters such as rainfall, temperature, pH, electrical conductivity and dissolved oxygen of water were recorded. The sampled population showed a slight predominance of males (55%), however females were larger and heavier. Both sexes of L. piau showed positive allometric growth, indicating a higher increase of weight than length. The first sexual maturation of males occurred at smaller size, with 16.5 cm in total length than females (20.5 cm). During the reproductive period, the condition factor and gonadosomatic index (GSI) of L. piau were negatively correlated. This species has large oocytes with a high mean fecundity of 54.966 with synchronous oocyte development and total spawning
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The species Dasyatis marianae inhabits coastal areas associated with coral reefs, considered endemic to the northeast of Brazil, occurring from the State of Maranhão to the south of Bahia. Specimens of this species are commonly sighted by divers and fishermen in the area of Maracajaú reefs, a complex reef that is part of the Environmental Protection Area of Coral Reefs (EPACR), which was developed in this study about the ecology and biology of the D. marianae, in order to characterize aspects of population structure in the area of the reef complex of Parracho de Maracajaú. We analyzed 120 specimens caught by artisanal fishing site of the size, weight, sex, stage of maturity and stomach contents. Most subjects were adult males (1.7:1) and was more abundant for rays with lengths between 25 and 29cm of LD, where females reach larger sizes, a feature common to other rays. The largest specimens were captured in the area of seagrass, which is preferred for the species. The distribution of species in the area showed an ontogenetic and sexual segregation, where the youthful occur near the beach, which is a likely area for nursery and growth of the adult females prevail in the seagrass, which apparently has a high prey availability, and Adult males are more distant, a higher proportion occurring in outlying areas, suggesting a habit more exploratory than the females. The evaluation of the reproductive system indicated 3 reproductive cycles per year, one young per pregnancy, and showed that the mature males were smaller than females. The cubs of D. marianae size at birth 12 to 15cm LD. As for diet, the species was characterized as carnivorous crustacean specialist. The performance of visual censuses in different localities allowed to evaluate the density of D. marianae in different environments of the complex. The species occurs in greater numbers in seagrass, environment very important for the conservation of the species. 100 individuals of D. marianae marked in reef complex area enrolled in a recapture rate of 3%. Some behavioral aspects were evaluated, as diurnal pattern of activity, interaction with cleaning and fish Pomacanthus paru followers as Lutjanus analis and Carangoides bartholomaei. Overall, much of the information obtained should be used for management of the species
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Conselho Nacional de Desenvolvimento Científico e Tecnológico
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The reproductive ecology of fish plays a key role both for rational exploitation methods and for protective measures of natural stocks. The purpose of this study was to analyze the reproductive aspects of the damsel-fish, Stegastes fuscus, during October 2004 to September 2005, in the coastal rocky reefs of Búzios Beach, Nísia Floresta, RN. Fish were captured using hooks and hand nets, during low tide. Reproduction was determined using sexual ratio, mean length of first maturation (L50), absolute fecundity and macroscopic characteristics of gonads. The following parameters were related to gonadosomatic index (GSI): condition factor (CF), hepatosomatic index (HSI), rain fall and temperature. In relation to sex distribution, it was observed that 78% were females and 22% were males. The L50 was 6.2 cm for females and 7.0 for males. Average fecundity was 6832 oocytes. Results showed that S. fuscus had better body condition in the months prior to spawning, particularly during initial and intermediate stages of maturation. Five stages of gonadal maturation were identified through macroscopic analysis: immature, in maturation, mature, spent and resting. The HSI was inversely related to the GSI. This was possibly due to the reproductive cycle of this species which was associated to the dry period of this region. During this period, low rain fall and high temperatures provide an propitious reproductive condition for the study species
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The expansion of shrimp farming has caused a series of environmental impacts, often as a result of lack of planning and adequate management. Organic aquaculture has emerged as an alternative to conventional shrimp farming, and differently, aims at the economical, ecological and farming potential of other organisms, such as fishes, oysters and seaweeds. The present study aimed at evaluating the biological diversity and abundance of the ichthyofauna associated to Litopenaeus vannamei organic culture at PRIMAR farm (Rio Grande do Norte, Brazil). The sampling period consisted of four culture cycles (1, 2, 3, and 4) accomplished in four grow-out ponds (V1, V7, V2, and V4) in 2005. The first two culture cycles were carried out during the rainy season, and the last two cycles, during the dry season. Environmental (temperature, salinity, transparency, and rainfall), biodiversity (diversity and uniformity and abundance indexes) of the ichthyofauna, and shrimp productivity data were collected throughout these four culture cycles. The results obtained for the environmental variables showed that both salinity and transparency oscillated in a significant way (p < 0.001) between culture cycles. In relation to the abundance of the ichthyofauna, fifty four species associated to the organic culture of Litopenaeus vannamei were collected and identified at PRIMAR. For the biodiversity criterion, larger species richness (S = 46) and uniformity (E = 0.59 ± 0.16) were observed during cycles 3 and 4 than in cycles 1 and 2 (S = 41 and E = 0.15 ± 0.12). A positive and significant correlation was obtained for the transparency with diversity and uniformity of fish species between cycles 1 and 2 (wet season) and cycles 3 and 4 (dry season) (p < 0.017 - Shannon Index; p < 0.008 - Pielou Index, respectively). A correlation could not be established between shrimp productivity and fish biomass. However, fish biomass decreased from cycles 1 and 2 to cycles 3 and 4, concomitant with an increase in shrimp productivity, most probably due to a higher (from 58.0% to 71.0%) shrimp survival. Regarding the culture potential of the ichthyofauna, three species (Mugil curema, Mugil liza and Chaetodipterus faber) were identified as potential farming alternatives, either singly or in consortium with Litopenaeus vannamei. A fourth species (Centropomus undecimalis) was indicated as an alternative for single culture or in consortium with other fish species. In conclusion, the large diversity of estuarine fishes associated to Litopenaeus vannamei farming observed at PRIMAR clearly indicated the ecological feasibility for organic aquaculture in northeastern Brazil
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Worldwide, families Carangidae and Rachycentridae represent one of the groups most important commercial fish, used for food, and great potential for marine aquaculture. However, the genetic bases that can underpin the future cultivation of these species, cytogenetic between these aspects are very weak. The chromosomal patterns have provided basic data for the exploration of biotechnological processes aimed at handling chromosomal genetic improvement, such as induction of polyploidy, androgenesis and ginogenesis, as well as obtaining monosex stocks and interspecific hybridizations. This paper presents a comprehensive cytogenetic survey in 10 species, seven of the family Carangidae and the monotypic family Rachycentridae. Classical cytogenetic analysis and in situ mapping of multigene sequences were employed, and additionally for the genus Selene and morphotypes of Caranx lugubris, comparisons were made using geometric morphometrics. In general, conservative species exhibit a marked chromosome number (2n=48). Although present in large part, different karyotypic form, retain many characteristics typical of chromosomal Order Perciformes, the high number of elements monobrachyal, Ag-NORs/18S rDNA sites and heterochromatin simply reduced, preferably centromeric. The main mechanisms involved in karyotypic diversification are the pericentric inversions, with secondary action of centric fusions. In addition to physical mapping and chromosome detail for the species are presented and discussed patterns of intra-and interspecific diversity, cytotaxonomic markers. This data set provides a better understanding of these patterns caryoevolutyonary groups and conditions for the development of protocols based on Biotechnology for chromosomal manipulation Atlantic these species
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without practical results so far. Protocols used in biotechnological cultured aquatic organisms aimed at increasing growth rates and disease resistance, have been studied and perfected. Among the available techniques, the application of chromosomal manipulation, although still nascent, is presented as a tool aimed at mitigating ecological and economical issues in shrimp farming. The polyploidization artificial method already employed in fish and shellfish, has been widely researched for use in farmed shrimp. Some limitations of this method of expansion in shrimp refer to a better knowledge of cytogenetic aspects, the level of sexual dimorphism and performance in growing conditions. To contribute on some of these issues, the present study aimed to characterize cytogenetic species Litopenaeus vannamei (Decapoda) and Artemia franciscana (Anostraca), analyze the effectiveness of methods for detection of ploidy, through the use of flow cytometry in processes of induction polyploidy cold thermal shock at different stages of development of newly fertilized eggs. Additionally, aimed also the qualitative and quantitative comparison of larval development between diploid and polyploid organisms, besides the identification of sexual dimorphism in L. vannamei, through geometric morphometrics. The results provide information relevant to the improvement and widespread use of biotechnological methods applied toward national productivity in shrimp farming
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Perciformes are dominant in the marine environment, characterized as the largest and most diverse fish group. Some families, as Gerreidae, popularly known as silver jennies, carapebas, or mojarras have a high economic potential to marine fish farming, natural explotation and game fishing. Genetic information of these species are of fundamental importance for their management and production. Despite exist over 13,000 marine fish species described, only 2% were cytogenetically analyzed and less than 1% have some reproductive characteristics known. Induced breeding, cytogenetic characterization and cryopreservation of gametes, represent important areas in applied fish studies. In this project cytogenetic analyzes were performed to acess genetic aspects of Gerreidae species, distributed in coastal and estuarine regions of Northeast Brazil. Different methods for identifying chromosomal regions were employed using conventional techniques (Ag-NORs, C-banding), staining with base-specific fluorochromes (DAPI-CMA3), and physical mapping of ribosomal genes 18S and 5S rDNA, through hybridization in situ with fluorescent probes (FISH). The six species analyzed showed remarkable chromosome conservatism. The 18S and 5S ribosomal genes when analyzed in phylogenetic perspective demonstrate varied evolutionary dynamics, suggesting ocurrence of stasis process in some groups and greater dynamism in others. Double FISH with 18S and 5S probes showed both how efficient cytotaxonomic markers in the homogeneous karyotypes of this group of species. The karyotypic pattern identified in addition to the evolutionary aspects of karyotype, are suggestive of existence of low potential of post-zygotic barrier, prompting further research to prospect for artificial interspecific hybridization of these species of commercial importance
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Oligoplites palometa (Cuvier) and Oligoplites saurus (Bloch & Schneider) (Osteichthyes: Carangidae) are coastal pelagic fish species. The objective of this study was to investigate the effect of parasitism by isopods and the reproductive biology of the leather jack, Oligoplites spp. A total of 113 individuals of Oligoplites spp (35 of O. saurus and 78 of O. palometa) were captured during the period between January, 2005 and July, 2007 from the coastal waters of Natal, RN. The morphometric and meristic characters were registered; macroscopic analyses were done to collect the isopod parasites and the gonads were observed to verify the reproductive aspects. The crustacean isopod parasite, Cymothoa spinipalpa (Isopoda: Cymothidae) was encountered on the tongue in the oral cavity in both fish hosts. The parasitic indices of C. spinipalpa showed high values of prevalance of 51,4% for O. saurus and 64,1% for O. palometa. The host presented significant correlations between body mass and body length of O. palometa and the number of parasites. Body lengths of female C. spinipalpa were small due to the limited space available in the oral cavity of the host. There was a significant difference in the sex ratio of O. palometa, males outnumbered the females. The isopod parasites showed specificity to the oral cavity of hosts. Macroscopic analyses of gonads showed four stages of gonadal development for both sex of O. palometa: immature, maturing, mature and spent
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The marine fish white mullet, Mugil curema Valenciennes, 1836 (Osteichthyes: Mugilidae) exhibits a wide geographical distribution, being common in the Brazilian coast and is an important component of the artisanal fisheries. The objective of this study was to investigate the reproductive biology of M. curema in the coastal waters of Rio Grande do Norte. Fish samples were captured on a monthly basis during August, 2008 to July, 2009. The fish specimens were numbered, weighed, measured, dissected and their gonads were removed, weighed, their sex and gonadal development were identified. The length-weight relationship was determined for males and females. The sex ratio, the size at first gonadal maturation and gonadosomatic index (GSI) were calculated and ovarian development was investigated using macroscopic and histological techniques. The fecundity, spawning type and the reproductive period of the species were determined. A total of 366 specimens (186 males and 180 females) were captured. The sex ratio was 1:1 and the females were heavier than males. The estimated values of the angular coefficient for both sexes suggest that the species has isometric growth. The size at which 50% of the population began the process of maturation was 25.9 cm of total length for grouped sex. The macroscopic characteristics of the ovaries showed four stages of development: immature, maturing, mature and spent. However, the microscopic characteristics of the ovaries showed five stages of development: immature, early maturing, late maturing, mature and spent. The development of oocytes indicated five phases: Chromatin-nucleolus (phase I), initial perinucleolar (phase II), final perinuclear (phase II), formation of vitelline vesicle or yolk (phase III), vitellogenic (phase IV) and complete vitellogenesis (phase V). The species has a prolonged spawning period, with two peaks coinciding with the rainy season.
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Food habits and morpho-histology of the digestive tract of marbled swamp eel, Synbranchus marmoratus (Block, 1917) were investigated. The fish samples were captured during August, 2007 to July, 2008 in the Marechal Dutra reservoir, Acari, Rio Grande do Norte. The rain fall data was obtained from EMPARN. The fish captured, were measured, weighed, dissected, eviscerated and individual stomach weights were registered. The stomach contents analyses were carried out based on volumetric method, points, frequency of occurrence and applying the Index of Relative Importance. The degrees of repletion of the stomachs were determined besides the Index of Repletion relating to feeding activity variations and frequency of ingestion during the rainy and dry seasons. The rainfall varied from 0 mm a 335 mm with a mean value of 71.62 mm. Highest rainfall of 335.5 mm was registered in March, 2008 and August to December was the dry period. During the dry period the study species presented high degrees of repletion of the stomachs, with a peak value in the month of September (mean = 4.54; ± SD = 0.56). The minimum mean value of = 3.99 ± SD = 0.25 was registered in the month of May during the rainy period. The stomach contents of S. marmoratus registered show that this fish prefers animals, 78.22% of crustaceans 2.85% of mollusks, 3.25% of fish, 1.4% of insects and 13.5% of semi-digested organic matter, thus characterizing the study species as a carnivore with a preference for crustaceans. The morpho-histological aspects of the digestive tract of S. marmoratus indicate that the mouth is terminal adapted to open widely, thin lips with taste buds, small villiform teeth forming a single series on maxillas, four pairs of branchial arches with short and widely spaced branchial rays. The oesophagus is short and cylindrical with a small diameter. The oesophagus wall is thick with mucas surface and internal parallel folds. The stomach is retilinical in form, presenting cardiac, caecal and pyloric portions. The caecal portion is long and is intermediary in position between the cardiac and pyloric portions. The cardiac portion of the stomach is short and cylindrical formed of simple epithelial cylindrical mucus cells. The caecal portion is long with narrow walls, a big cavity and smaller folds which give rise to gastric glands. The phyloric portion has no glands and primary or secondary mucas folds. The morphohistological aspects of the digestive tract of S. marmoratus indicate its adaptation to a carnivorous feeding habit
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Reproductive strategy of the hermaphrodite fish the marbled swamp eel, Synbranchus marmoratus (Bloch, 1795) (Osteichthyes: Synbranchidae) was investigated in the Marechal Dutra reservoir, Acari, Rio Grande do Norte, using fish samples captured monthly during the period of July 2010 to July 2011. The limnological parameters and rainfall were verified. The captured fish specimens were numbered, weighed, measured, dissected and their gonads and liver were removed, weighed and identified as to sex and developmental stages of gonads. The length-weight relationship was determined for grouped sex. The size of first gonadal maturation, gonadosomatic index (GSI), condition factor (K) and hepatosomatic index (HSI) were calculated. The development stages of the gonads were investigated using macroscopic and histological techniques, besides the fecundity and reproductive period. The macroscopic characteristics and the histological development of gonads confirmed the four different sexual types in the sampled population: primary males, females, intersex and secondary males. The secondary males were bigger and heavier than all the other types. This species showed a negative allometric growth with a higher increase in length than weight. The size at which 50% of the females began the process of gonadal maturation was 43.5 cm of total length, and for secondary males it was 58.5 cm. Condition factor showed two peaks in February and in April 2011. IGS indicated a reproductive period from July to September 2010 and was negatively correlated with the condition factor and rainfall. IGS showed a negative correlation when compared with the condition factor and the rainy season. HSI was highest in February ad lowest in December. The reproductive period of this species occurs between the end of the rainy season and the beginning of the dry season. S. marmoratus presents a seasonal reproductive strategy which optimizes its reproductive success under the semiarid climatic conditions
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The composition of ichthyofauna discarded by trawling shrimping, their reproductive status and feeding ecology were studied on the beaches of Basin Rio Grande do Norte, Brazil. Fish were collected monthly in the year of 2012. During biometrics, portions of the digestive tract and of gonads were removed, fixed in formalin 10% and Bouin, respectively, for be submitted to histological processing by the techniques of hematoxylin-eosin. Stomach content analyzes were performed using the methods of Frequency of Occurrence and Volumetric and was calculated the repletion index. Throughout the study period were recorded a total of 49 species. The fish assemblages differed between sections monitoring, with the highest abundance, biomass and indices of richness and diversity in sections B, D and C. Already the excerpt A, showed higher values for dominance and equitability. In the cluster analysis according to the faunal similarity was observed the formation of three groups: group I formed by excerpts B and D, group II by excerpt C and group III formed by excerpt A. The assessment of reproductive stage revealed that the fish assemblages discarded by trawling are composed mainly of juveniles. Regarding the feeding ecology, the species Larimus breviceps, Menticirrhus littoralis and Pomadasys corvinaeformis characterized as carnivorous with tendency to carcinofagia. Already Conodon nobilis characterized as carnivorous with tendency to piscivory, but all proved generalist-opportunistic with increase of feeding activity during drought. The dendrogram of grouping of the species developed based on the food items used shows the formation of four groups: Group I consists of species that feed mainly of "gastropod" and "sediment"; group II of "teleost fish"; the group III of "crustacea" and group IV of "echinodermata" and "bivalve". The anatomical and histological characteristics of the digestive tract were consistent with the dietary habits of the analyzed species. In this context, the Costa Branca of Rio Grande do Norte can be considered a feeding site and recruitment for juveniles, which, opportunistically, utilize resources associated with the background
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The occurrence of human cancer in the municipality of Lucrécia (RN, Brazil) has shown high frequencies (INCA, 2007). Tests of micronucleus (MN) and nuclear abnormalities (NA) were performed to assess the genotoxic potential of water from the Lucrécia dam, which is located in a semi-arid region under the influence of crop irrigation and irregular rainfall. Water samples were collected in this source for analyzing the concentration of cyanobacteria, metals and radioactivity. Erythrocytes of Nile tilapia (Oreochromis niloticus) were collected in dam and cells of human oral mucosa in the urban area of this municipality for the bioassays of MN and NA. In fish were also analyzed concentrations of metals in samples of liver and gills. The genotoxicity tests with biological samples of fish and humans have shown significant increases in the frequencies of MN and NA (p ≤ 0.05) and are indicative of increased DNA damage in relation to the control groups. In conclusion, the results obtained from water samples and biological municipality of Lucrécia indicates that the presence of chemical and microbiological pollutants, and increase of genotoxic in human of this municipality. We suggest the implementation of advanced water treatment, to prevent further degradation of the aquatic environment and decrease in the life quality. This research of environmental quality assessment was performed in order to contemplate a multi and interdisciplinary character of this water resource and that can induce genotoxic damage in the organisms in this study region