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Hook selectivity of the pacu Piaractus mesopotamicus (Holmberg, 1887) in the Pantanal, the state of Mato Grosso do Sul, Brazil
Peixer, J.;Petrere Jr., M.;
Brazilian Journal of Biology , 2007, DOI: 10.1590/S1519-69842007000200021
Abstract: the pacu piaractus mesopotamicus is the most captured fish species in the pantanal, mato grosso do sul state, and since 1994, its maximum sustainable yield had already been exceeded. its capture is carried out only by hooks, as mesh gears are forbidden either for professional or for recreational fishing. the aim of this study was to determine selectivity for different hook sizes used in p. mesopotamicus fishing and to verify which sizes capture only adults. data were collected in the rivers miranda, aquidauana, and vermelho, in january, march, and april 2002. six longlines with eight hook sizes were used and we adopted the hook opening as a measure related to selectivity. different hooks captured individuals of the same length and their medians were similar, evidencing the great overlap among sizes. regression results showed no significant relationship between ln[c2 (l)/c1 (l)] and total length of captured individuals. in addition, the kolmogorov-smirnov test also did not detect significant differences in the size of captured fish. several hypotheses, such as the selectivity models, shape of selection curves, scarcity of large fishes, and behavior are used in order to explain the absence of hook selectivity for this species. size of recruitment for this gear was 28 cm of total length, when individuals are still immature.
Efeito da granulometria do milho no desempenho de juvenis de pacu, Piaractus mesopotamicus (Holmberg, 1887)
Polese, M.F;Vidal Junior, M.V;Mendon?a, P.P;Tonini, W.C.T;Radael, M.C;Andrade, D.R;
Arquivo Brasileiro de Medicina Veterinária e Zootecnia , 2010, DOI: 10.1590/S0102-09352010000600025
Abstract: the effect of different particle size of corn ration on the performance of juvenile pacu, piaractus mesopotamicus, was evaluated. a total of 120 juveniles with an initial weight of 8.42±0.89g, total length 7.03±0.20cm, standard length, 6.32±0.13cm, and height 3.21±0.11cm, were distributed into 20 tanks (300l), at a density of six fish per experimental unit (tank), in a completely randomized design with five treatments consisting of different particle sizes 850, 710, 500, 300, 150μm of corn in the ration composition. each treatment had four replicates. among all treatments, the best animal performance was achieved with the ration with corn particle size of 150μm, reaching a feed conversion ratio of 1.38, whereas for larger feed grain size, it was 1.61. thus, the particle size of 150μm is recommended.
Yield per recruit of the pacu Piaractus mesopotamicus (Holmberg, 1887) in the pantanal of Mato Grosso do Sul, Brazil
Peixer, J.;Catella, AC.;Petrere Júnior, M.;
Brazilian Journal of Biology , 2007, DOI: 10.1590/S1519-69842007000300023
Abstract: among the several fish species comercially exploited at the pantanal of mato grosso do sul, the "pacu" (piaractus mesopotamicus) stands as one of the most important. information regarding its exploitation level is necessary for the proper management of its stocks. between 1996 and 1997 data on total length of the pacu were collected on a monthly basis from specimens caught by professional and sport fishers in the municipality of corumbá. these data were used to estimate growth parameters and to assess the exploitation level for this species, applying the beverton and holt yield per recruit model. length frequency analysis, carried out with the software fisat (elefan), was used to estimate growth parameters: 1996: l¥ = 87.20 cm; k = 0.34 year-1; f′=3.41; c = 0.74; wp = 0.81; longevity = 8.40 years; and 1997: l¥ = 86.50 cm; k = 0.34 year-1; f′=3.40; c = 0.60; wp = 0.80; longevity = 8.40 years. the value for t0is -0.363 years for mean values of l¥ and k. the weight-length relationship, calculated from data derived from experimental fisheries carried out in 1999 and 2000, is described by the equation: w = 0.048lf2.835. estimated mortalities and survival rates were: 1996: z = 1.51 year-1; m = 0.62 year-1; f = 0.89 year-1; s = 21.9%; and 1997: z = 1.65 year-1; m = 0.63 year-1; f = 1.02 year-1; s = 19.1%. the yield per recruit analysis showed the following values: fpresent= 0.96 year-1; fmax = 0.67 year-1 ; f0.1 = 0.51 year-1 (for lc = 26.7 cm). these results suggest that the pacu is overexploited in the area, so that restrictive measures are in need to manage the pacu fisheries.
Alimenta??o e comportamento de larvas de pacu, Piaractus mesopotamicus (Holmberg, 1887)
Beerli, Eduardo Lopes;Logato, Priscila Vieira Rosa;Freitas, Rilke Tadeu Fonseca de;
Ciência e Agrotecnologia , 2004, DOI: 10.1590/S1413-70542004000100020
Abstract: the objective of this research was to evaluate the effect of natural and artificial diets on the development and behavior of pacu (piaractus mesopotamicus) larvae, between the 2nd and 10th day post hatch. the larvaes were kept in 30l - plastic boxes (n = 30 boxes), in constant flow-through. the larvae density was 10 post-larvae/l (300 larvae/box). six diets with 4 sampling days (4, 6, 8 and 10 days post-hatch, n = 30 larvae) using 5 repetitions were tested. the diets were: t1- commercial feed, t2- plancton, t3- artemia, t4- plancton + feed, t5- artemia + feed and t6- artemia + plancton. larvaes were fed 6 times a day: 4, 8, 12, 16, 20 and 24 hours. the water temperature was kept constant at 27oc, dissolved oxigen was kept between 6.16 ± 0.34 and ph between 7,16 ± 0,22. at the end of the experiment (10th day post-hatch), the larvaes that received diet containing artemia + plancton (t6) were longer (8.35 mm) and heavier (3518 μg body weight), compared to the larvae fed with the other tested diets. the larvae should be in the laboratory for 6 days after hatch, being feed from the 3rd day after hatch. before the 6th day, the larvae have the gas bladder completely full and swim continuously.
Reproductive biology of pacu Piaractus mesopotamicus (Holmberg, 1887) (Teleostei: Characidae) in the Cuiabá River Basin, Mato Grosso, Brazil
Costa, Rosa Maria Rodrigues da;Mateus, Lúcia Aparecida de Fátima;
Neotropical Ichthyology , 2009, DOI: 10.1590/S1679-62252009000300012
Abstract: the purpose of this study was to analyze the reproductive strategy and life-history traits involved in the reproductive processes of p. mesopotamicus in two regions of the cuiabá river basin, the first of these encompassing its headwaters (cuiabazinho river - rosário oeste) and the other the flood area of the cuiabá river (porto cercado - poconé). a total of 391 individuals were sampled monthly from august 2006 to july 2007, 159 from the headwaters and 232 from the flood area. the size structure indicated that the females in the headwaters attain longer lengths than the males, while no differences in length were found in the flood area. females predominated in the headwaters, while males outnumbered females in the flood area. the reproductive period in the headwaters extended from october to march, but was restricted to october and november in the flood area. feeding activity showed significant differences in both sexes between the stages of gonadal maturation, with the highest values recorded in stages of gonadal inactivity. the length at first maturity was 34.89 cm and the length at which all specimens were ready for reproduction was 44 cm at both sampling sites. the spawning type was total and fecundity was positively correlated to the size of the female.
Parametros sangüíneos de pacu Piaractus mesopotamicus (Holmberg, 1887) alimentados com dietas suplementadas com cromo trivalente em duas densidades de estocagem = Hematological parameters of pacu Piaractus mesopotamicus (Holmberg, 1887) fed diets supplemented with trivalent chromium in two stocking densities
Rodrigo Yudi Fujimoto,Marcello Pardi de Castro,Mauricio Later?a Martins,Flávio Ruas de Moares
Acta Scientiarum : Animal Sciences , 2007,
Abstract: O objetivo deste trabalho foi avaliar os efeitos da suplementa o com cromo trivalente (0, 6, 12 e 18 mg kg-1 de ra o) sobre as variáveis hematológicas de Piaractus mesopotamicus, mantidos em duas densidades de estocagem (4 e 20 kg m-3). Os mantidos na maior densidade e alimentados com dietas suplementadas com 0 e 6 mg de cromo kg-1apresentaram redu o do número de linfócitos circulantes, sugerindo má adapta o a essa condi o de alta densidade. Nas dietas suplementadas com 12 e 18 mg kg-1, tal efeito n o foi observado, porém verificou-se aumento do número de trombócitos no tratamento com 12 mg de cromo kg-1. A inexistência de diferen a significativa entre os tratamentos, aos 30 dias, sugere a adapta o dos peixes ao tipo de alimento e à situa o de alta densidade. Portanto, nas condi es deste ensaio, a suplementa o com 12 e 18 mg de cromo kg-1 é interessante como estratégia alimentar durante 15 dias. This work evaluated the effects of chromium supplementation on thehematological parameters of Piaractus mesopotamicus Holmberg, 1887 maintained in two stocking densities. Fish were fed diets supplemented with 0, 6, 12 and 18 mg trivalent chromium kg-1 dry ration and maintained at 4 and 20 kg m-3. The fish under high stockingdensity and fed diets supplemented with 0 and 6 mg kg-1 showed reduction in the number lymphocytes, which suggests non-adaptation to this condition of high density. This was not observed in fish fed diets supplemented with 12 and 18 mg chromium kg-1, but an increasein the number of thrombocytes was evident. The lack of difference between treatments after 30 days may suggest a possible adaptation of fish to the situation. It can be added that supplementation with 12 and 18 mg chromium kg-1 is an interesting feeding strategy for aperiod of 15 days.
Structural and morphological features of Piaractus mesopotamicus (Holmberg, 1887) gills
SEVERI, W.;RANTIN, F. T.;FERNANDES, M. N.;
Revista Brasileira de Biologia , 2000, DOI: 10.1590/S0034-71082000000300014
Abstract: the pacu piaractus mesopotamicus (holmberg, 1887), is a commercially important serrasalmid fish endemic to the paraná-paraguay river basin, and one of the most widely cultivated native fish species in the neotropics. as a migratory species, also inhabiting temporary pools subjected to hypoxic conditions, the species presents a high plasticity concerning respiratory adaptations. in order to supplement basic knowledge on the respiratory physiology and morphology of this species, some structural features of pacu gills, such as filament and lamellae structure, and circulatory pattern are described in this paper.
Structural and morphological features of Piaractus mesopotamicus (Holmberg, 1887) gills
SEVERI W.,RANTIN F. T.,FERNANDES M. N.
Revista Brasileira de Biologia , 2000,
Abstract: The pacu Piaractus mesopotamicus (Holmberg, 1887), is a commercially important serrasalmid fish endemic to the Paraná-Paraguay River basin, and one of the most widely cultivated native fish species in the Neotropics. As a migratory species, also inhabiting temporary pools subjected to hypoxic conditions, the species presents a high plasticity concerning respiratory adaptations. In order to supplement basic knowledge on the respiratory physiology and morphology of this species, some structural features of pacu gills, such as filament and lamellae structure, and circulatory pattern are described in this paper.
Incubation of eggs and larvae of pacu (Piaractus mesopotamicus holmberg, 1887) in israeli and woynarovich incubators Incuba o de ovos e larvas de pacu (Piaractus mesopotamicus holmberg, 1887) em incubadoras do tipo israelense e woynarovich  [cached]
Luis Ricardo Jayme Guerreiro,Jeferson Antonio Dias Dias,Darci Carlos Fornari,Ricardo Pereira Ribeiro
Semina : Ciências Agrárias , 2011,
Abstract: The aim of this work was to evaluate the fertilization and hatching rates of eggs of Piaractus mesopotamicus hormonally induced, and the survivorship and percentage of defective larvae at 48 and 72 hours after hatching in Israeli and Woynarovich hatcheries. A pool of eggs and larvae obtained from ten females and twenty males was used. The experimental design was completely randomized with two treatments and four replicates. The fertilization averages did not demonstrate significant differences (P > 0,05) between the treatments. Hatching values (%) were significantly higher (P < 0,05) in Woynarovich hatcheries; the survivorship (%) of the larvae at 48 and 72 hours after hatching were significantly higher (P < 0,05) in Israeli hatcheries; and the percentage of defective larvae was significantly lower (P < 0,05) in Israeli hatcheries in both evaluation times. According to the results, the Israeli hatcheries present better conditions for larvae survivorship. O objetivo neste estudo foi avaliar as taxas de fertiliza o e eclos o dos ovos de Piaractus mesopotamicus induzidos com extrato de hipófise, além da sobrevivência e porcentagem de larvas defeituosas após 48 e 72 horas da eclos o em incubadoras do tipo “Israelense” e “Woynarovich”. Utilizou se um “Pool” de ovos e larvas obtidas de 10 fêmeas e 20 machos. O delineamento experimental foi totalmente casualisado com dois tratamentos e quatro repeti es. As médias de fertiliza o n o demonstraram diferen as significativas (P > 0,05) entre as incubadoras. Os valores de eclos o (%) foram significativamente maiores (P < 0,05) nas incubadoras do tipo Woynarovich, a sobrevivência (%) das larvas após 48 horas da eclos o foi significativamente maior (P < 0,05) nas incubadoras do tipo Israelense, o mesmo foi observado após 72 horas da eclos o. A porcentagem de larvas defeituosas foi significativamente menor (P < 0,05) nas incubadoras do tipo israelense nos dois períodos avaliados. De acordo com os resultados obtidos, as incubadoras do tipo “Israelense” demonstraram melhores condi es para a sobrevivência das larvas.
Seletividade alimentar de organismos-alimento por formas jovens de pacu Piaractus mesopotamicus (Holmberg, 1887) e curimba Prochilodus lineatus (Valenciennes, 1836) = Selective feeding of food organisms by fish larvae of Piaractus mesopotamicus (Holmberg, 1887) and Prochilodus lineatus (Valenciennes, 1836)  [cached]
Nandeyara Ribeiro Marques,Carmino Hayashi,Eliana Maria Galdioli,Carlos Eduardo Bento Fernandes
Acta Scientiarum : Biological Sciences , 2007,
Abstract: Objetivou-se avaliar a sele o alimentar de organismos-alimento por formas jovens de pacu (Piaractus mesopotamicus) e curimba (Prochilodus lineatus) com diferentes idades (6, 12, 19 e 26 dias), na presen a e ausência de Pistia stratiotes. Foram utilizados quatrotratamentos (T1 = pacu + P. stratiotes; T2 = pacu; T3 = curimba + P. stratiotes; T4 = curimba) e quatro repeti es. A cada sete dias, foram coletadas 24 larvas de cada espécie de peixe dos tanques, sendo estas mantidas em jejum por 24 horas. Depois de distribuídas nos aquários com plancton, as larvas permaneceram por três horas, sendocoletadas e fixadas para análise, juntamente com as amostras de água. Os tratos digestórios das larvas foram retirados e analisados sob microscópio óptico. Observaram-se diferen as estatísticas na seletividade alimentar de organismos planct nicos por larvas de mesmaespécie, em diferentes idades e também entre larvas de espécies diferentes, com mesma idade, n o diferindo quanto à presen a ou ausência de P. stratiotes. As formas jovens de pacu e curimba selecionaram organismos similares aos seis dias de idade, passando por altera es até o 26o dia. à medida que se desenvolveram, as larvas de pacu passaram a selecionar cladóceros e ostrácodos e as de curimba, protozoários e algas. Theobjective was to evaluate the feeding selection of food organisms for two species of fish larvae (pacu and curimba) at different ages (6, 12, 19 and 26 days after eclosion), in the presence or absence of Pistia stratiotes. Four treatments were used (T1 = pacu + P. stratiotes; T2 = pacu; T3 = curimba + P. stratiotes; T4 = curimba) and four replications. Every seven days, 24 fish larvae of each species were collected, and kept without food for 24 hours. Afterbeing distributed in the aquariums with plankton, the larvae stayed for three hours, and were collected and prepared for analysis, along with the water samples. The digestive tract of the fish larvae were removed and analyzed under an optic microscope. Statistic differences in selective feeding of plankton organisms were reported for larvae of the same species, of different age groups and also among larvae of different species of the same age. There were no observed differences as for the presence or absence of P. stratiotes. The fish larvae of pacu and curimba selected similar organisms at six days old, with changes until the 26th day. As they developed, the pacu larvae began to select cladocerans and ostracods, and the curimba selected protozoans and algae.
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