ABSTRACT
Seven hundred and twenty four fish specimens were captured from March to September 2016. The materials used in the current study were cast nets, hand nets. Eight cyprinid fish species were studied for their length weight relationships. Parameter b in the LWR was 3.03, 3.06, 3.02, 2.29, 2.82, 3.43, 2.73 and 2.47 for Schizothorax plagiostomus, Schizothorax esocinus, Racoma labiata, Tor putitora, Barilius vagra, Garra gotyla, Puntius ticto and Arassius auratus respectively. Current study is the first attempt on the LWRs of cyprinid species, provide a baseline approach for conservation and /management of local fish fauna of economic importance.
Um total de 724 espécimes de peixes foi capturado de março a setembro de 2016. Os materiais usados no presente estudo foram redes de lançamento, redes de mão. Oito espécies de peixes ciprinídeos foram estudadas quanto às suas relações peso/comprimento. O parâmetro b no LWR foi 3,03, 3,06, 3,02, 2,29, 2,82, 3,43, 2,73 e 2,47 para Schizothorax plagiostomus, Schizothorax esocinus, Racoma labiata, Tor putitora, Barilius vagra, Garra gotyla, Puntius ticto e Arassius auratus respectivamente. O estudo atual é a primeira tentativa sobre os LWRs de espécies de ciprinídeos, fornecendo uma abordagem de base para a conservação e o manejo da ictiofauna local de importância econômica.
Subject(s)
Animals , Cyprinidae/growth & development , Body Weights and Measures/veterinaryABSTRACT
Abstract Seven hundred and twenty four fish specimens were captured from March to September 2016. The materials used in the current study were cast nets, hand nets. Eight cyprinid fish species were studied for their length-weight relationships. Parameter b in the LWR was 3.03, 3.06, 3.02, 2.29, 2.82, 3.43, 2.73 and 2.47 for Schizothorax plagiostomus, Schizothorax esocinus, Racoma labiata, Tor putitora, Barilius vagra, Garra gotyla, Puntius ticto and Arassius auratus respectively. Current study is the first attempt on the LWRs of cyprinid species, provide a baseline approach for conservation and /management of local fish fauna of economic importance.
Resumo Um total de 724 espécimes de peixes foi capturado de março a setembro de 2016. Os materiais usados no presente estudo foram redes de lançamento, redes de mão. Oito espécies de peixes ciprinídeos foram estudadas quanto às suas relações peso/comprimento. O parâmetro b no LWR foi 3,03, 3,06, 3,02, 2,29, 2,82, 3,43, 2,73 e 2,47 para Schizothorax plagiostomus, Schizothorax esocinus, Racoma labiata, Tor putitora, Barilius vagra, Garra gotyla, Puntius ticto e Arassius auratus respectivamente. O estudo atual é a primeira tentativa sobre os LWRs de espécies de ciprinídeos, fornecendo uma abordagem de base para a conservação e o manejo da ictiofauna local de importância econômica.
ABSTRACT
Abstract Seven hundred and twenty four fish specimens were captured from March to September 2016. The materials used in the current study were cast nets, hand nets. Eight cyprinid fish species were studied for their length-weight relationships. Parameter b in the LWR was 3.03, 3.06, 3.02, 2.29, 2.82, 3.43, 2.73 and 2.47 for Schizothorax plagiostomus, Schizothorax esocinus, Racoma labiata, Tor putitora, Barilius vagra, Garra gotyla, Puntius ticto and Arassius auratus respectively. Current study is the first attempt on the LWRs of cyprinid species, provide a baseline approach for conservation and /management of local fish fauna of economic importance.
Resumo Um total de 724 espécimes de peixes foi capturado de março a setembro de 2016. Os materiais usados no presente estudo foram redes de lançamento, redes de mão. Oito espécies de peixes ciprinídeos foram estudadas quanto às suas relações peso/comprimento. O parâmetro b no LWR foi 3,03, 3,06, 3,02, 2,29, 2,82, 3,43, 2,73 e 2,47 para Schizothorax plagiostomus, Schizothorax esocinus, Racoma labiata, Tor putitora, Barilius vagra, Garra gotyla, Puntius ticto e Arassius auratus respectivamente. O estudo atual é a primeira tentativa sobre os LWRs de espécies de ciprinídeos, fornecendo uma abordagem de base para a conservação e o manejo da ictiofauna local de importância econômica.
Subject(s)
Animals , Cyprinidae , Rivers , PakistanABSTRACT
Aims: This study investigated Length-weight relationships and condition factors of fish species in Ebrie Lagoon (Aghien-Potou sector, C魌e d扞voire) Place and Duration of Study: Ebrie Lagoon (Aghien-potou sector) from April 2019 to March 2020. Methodology: study was conducted during 3 to 4 days continuously in Ebrie Lagoon (Aghien-Potou Sector). Furthermore, monthly fish samples were collected from commercial fishing area at random using gillnets, cast nets, traps, hooks and beach seines. Results: All Length-Weight regressions were highly significant with the coefficient of determination (r2) ranging from 0.61 in Schilbe mandibularis to 0.90 in Monodactylus sebae and Chrysichthys maurus. An isometric growth was observed for most of species except three of them namely Ethmalosa fimbriata, Pseudotolithus elongatus, and polydactylus quadrifilis. The k values varied from 0.19�001 in S. melanotheron to 6.10�3 in Monodactylus sebae. The values of b and k denote that the Ebrie lagoon could provide a favourable environment and suitable habitat for the growth of those fish species. Conclusion: The study provides basic information on length-weight parameters for twenty major fish species collected from Ebrie lagoon (Aghien-Potou sector). Three species namely Ethmalosa fimbriata, Pseudotolithus elongatus and Polydactylus quadrifilis exhibited a trend of positive growth whereas seventeen fish species showed isometric growth. The condition factor k was superior to 1 for 75% of the fish species and inferior to 1 for 25 % of the fish species. These growth trends denote that the lagoon could provide a favourable environment and suitable habitat for the growth of those fish species. Thus it would be interesting to create a protected area near the lagoon in order to ensure the protection of fish species.
ABSTRACT
Lutjanus argentiventris presents a large intertropical distribution within the Eastern Pacific, which is as important to fisheries now as it was in the pre-Hispanic period. The purpose of this article is to present an allometric model that enables the size and weight of L. argentiventris to be predicted, using the isolated bones found in archaeological and paleontological contexts or the stomach contents of ichthyophagous species. A modern collection of L. argentiventris from Ecuador was used, composed of 37 individuals covering a wide range of sizes and weights. The total length (TL), standard length (SL), and total fresh weight (W) of each individual was gathered. The TL of the sample ranged between 210 and 760 mm, the SL between 164 and 627 mm and the W ranged between 123 and 6550 g. The most frequent bones (15) and otoliths were chosen and 39 measurements were taken. The total length-weight relationship was W = 6E-06 TL3.1513 with R 2 = 0.997. In general, it was observed that the relationships between the TL and the bone measurements had a strong correlation (R² > 0.95). The allometric model will be useful not only for archaeologists but also for biologists working on historical ecology.(AU)
Lutjanus argentiventris presenta una distribución intertropical en el Pacífico Oriental, siendo una especie importante desde épocas prehispánicas hasta la actualidad. El propósito de este artículo es presentar un modelo alométrico que prediga la talla y el peso de L. argentiventris, usando restos óseos aislados encontrados en contextos arqueológicos y paleontológicos. Se empleó una colección de 37 individuos con tallas y pesos variados, provenientes del Ecuador. La longitud total (LT), la longitud estándar (LE) y el peso (P) de cada individuo fueron recolectados. La LT varió entre 210 y 760 mm, la LE entre 164 y 627 mm y el P entre 123 y 6550 g. Se escogieron los huesos más frecuentes (15) y los otolitos para realizar 39 mediciones. La relación de la longitud total y el peso fue P = 6E-06 TL3,1513 con un valor de R 2 = 0,997. En términos generales se observa que las relaciones entre la LT y las medidas de los huesos presentan una correlación fuerte (R² > 0,95). El modelo alométrico presentado puede utilizarse para predecir el tamaño y el peso, no sólo de L. argentiventris, sino también de sus congéneres, y será útil para arqueólogos y biólogos interesados en ecología histórica.(AU)
Subject(s)
Animals , Weights and Measures , Perciformes , Otolithic MembraneABSTRACT
ResumenPseudocurimata boulengeri, es una especie endémica del Ecuador, que da sustento a un importante grupo de familias de pescadores. Los antecedentes biológicos para esta especie corresponden a reportes en los sistemas loticos de la Provincia de los Ríos, se desconoce si estos parámetros siguen igual tendencia en un sistema lentico. En este trabajo se describe la proporción de sexo, la relación talla peso total, el desarrollo gonadal, la época de desove y el tamaño de primera madurez reproductiva de P. boulengeri, en el embalse de Chongón, Ecuador. Se capturaron peces con redes de enmalle (2.5") entre 2003 y 2009. La longitud total (Lt) de los peces capturados fue de 10.5 a 36.0 cm, el desove ocurre de noviembre a marzo y el tamaño de primera madurez para las hembras se estimó en 17.96 cm (Lt) y para los machos en 20.05 cm (Lt). La proporción de machos y hembras entre mayo y octubre, se ajusta a lo esperado (1:1), mientras que entre noviembre y abril, la proporción de hembras fue mayor que los machos, situación que coincide con la época de desove. Las características limnéticas y productivas del embalse, harían que esta especie pueda disponer de una mayor cantidad de alimento y un ambiente más favorable que le permitiría tener una postura más extendida en el año.
AbstractPseudocurimata boulengeri is an endemic species of Ecuador, which sustains a large group of fisher families. The biological data of this species correspond to reports from lotic systems of Los Ríos province; nevertheless, their trend in a lentic system is not yet known. This paper describes the sex ratio, length-weight relationship, gonad development, spawning season and size at reproductive maturity of P. boulengeri, inhabiting the lentic system of Chongón dam, Ecuador. Fish were caught between 2003 and 2009 using gill nets (2.5"). The total length (Lt) of caught specimens ranged from 10.5 to 35.5 cm, spawning occurred between the months of October and March, and size at first maturity for females was estimated at 17.9 cm (Lt) and 20.0 cm (Lt) for males. Between May and October male and female ratios were as expected (1:1), whereas for May, November and April, females ratios were higher than males, situation that coincided with the spawning season. The limnetic conditions and high production characteristics of Chongón dam, have promoted the availability of a great amount of food for this species, which may have allowed P. boulengeri to have a more extended reproductive season in this favorable environment.
Subject(s)
Animals , Male , Female , Reproduction/physiology , Sexual Maturation/physiology , Characiformes/physiology , Seasons , Sex Ratio , Body Weight , Ecuador , Characiformes/classificationABSTRACT
The relative condition factors (Kn) of the fishes Astyanax paranae, Phalloceros harpagos and Poecilia reticulata were used as a means of assessing the influence of environmental conditions on the well-being of sub - populations of these species, with the eventual aim of using them as bioindicators of disturbance in tributary streams of the Monjolinho River, in São Carlos - SP. The power-law curve generated by the length-weight relationship indicated a positive allometric growth for the three species studied. Overall, the canonical correspondence analysis (CCA) positively correlated average Kn of A. paranae with well oxygenated and oligotrophic environments, typical of conserved areas or near the natural state. For the average value of Kn obtained for Phalloceros harpagosspecies, there was no significant difference between natural and disturbed areas. However, the CCA positively correlated the mean Kn of the speciesP. reticulata from similar environments with higher trophic level, suggesting that this species is indicative of disturbance.
Os fatores de condição relativo (Kn) de Astyanax paranae, Phalloceros harpagos e Poecilia reticulata foram utilizados como ferramenta para avaliar a influência da qualidade ambiental sobre o bem estar de sub-populações destas espécies, visando utilizá-las como bioindicadoras de distúrbios em córregos afluentes do rio Monjolinho, no município de São Carlos - SP. A curva potencial gerada pela relação peso-comprimento indicou um crescimento do tipo alométrico positivo para as três espécies estudadas. No geral, a análise de correspondência canônica (CCA) correlacionou positivamente o Kn médio da espécie A. paranae com ambientes bem oxigenados e oligotróficos, característicos de áreas preservadas ou próximas do estado natural. Para o valor médio do Kn obtido para a espécie Phalloceros harpagos, não ocorreram diferenças significativas entre áreas naturais e perturbadas. Entretanto, a CCA correlacionou positivamente o Kn médio da espécie Poecilia reticulata a ambientes impactados, com maior grau de trofia, o que sugere que o fator de condição relativo desta espécie pode ser utilizado como indicador de distúrbios, neste caso, ocasionado pela poluição orgânica.
ABSTRACT
Growth and reproduction parameters of the yellow-mandi, Pimelodus maculatus Lacépède, 1803 (Siluriformes, Pimelodidae), were determined for the Cachoeira Dourada reservoir (GO/MG). The field work occurred throughout February 2007 to January 2008 (with the exception of December 2007). Gill nets with mesh sizes from 1.5 to 10 centimeters were placed in three different areas in the reservoir and were collected 24 hours later. A total of 538 specimens were captured, amongst which 242 were females, 219 were males and 77 could not have their sex determined. Sex ratio differed from 1:1 only during July 2007 and January 2008, with males and females predominating in each of those months. Males occupied the medium length classes (18.9 to 24.3 cm) while females were most abundant in the superior classes (from 27 to 37.8 cm).The growth constant K was statistically equal for males (K=0.1851) and females (K=0.1708), however, females P. maculatus may have a greater investment in reproductive tissue, a fact indicated by the elevated values of Kn and GSI during the summer. Bearing in mind that P. maculatus reproduces in the rainy season, a greater gain in weight is expected during the months before the reproduction season, and that after it occurs the fish loses fat and weight as a consequence of metabolic effort. Still, the absence of juveniles may be an indication that the species did not find in the reservoir the proper conditions for reproduction and growth of its fry.
O presente estudo procurou averiguar os parâmetros de crescimento e reprodução do mandi-amarelo, Pimelodus maculatus Lacépède, 1803 (Siluriformes, Pimelodidae), no reservatório de Cachoeira Dourada (GO/MG). As coletas ocorreram de fevereiro de 2007 a janeiro de 2008 (exceto em dezembro de 2007), em três pontos do reservatório, com auxílio de baterias de redes com malhas variando de 1,5 a 10,0 cm entre nós adjacentes durante 24 horas. Foi capturado um total de 538 indivíduos dentre os quais 242 fêmeas, 219 machos e 77 de sexo indeterminado. A proporção sexual diferiu de 1:1 em julho de 2007 e janeiro 2008, com o predomínio de machos e fêmeas, respectivamente. Os machos concentraram-se nas classes de comprimento medianas (18,9 a 24,3 cm) enquanto que as fêmeas nas superiores (de 27 a 37,8 cm). A constante de crescimento K foi estatisticamente igual entre machos (K=0.1851) e fêmeas (K=0.1708), no entanto, P. maculatus fêmeas parecem ter um maior investimento em tecido reprodutivo, fato indicado pelos elevados valores de Kn e IGS durante o verão. Tendo em vista sua desova durante o período chuvoso, é esperado um maior ganho de peso nos períodos que antecedem a reprodução e que após esse processo haja uma perda de gordura ou peso devido aos gastos metabólicos envolvidos. Ainda, a ausência de captura de P. maculatus juvenis pode ser uma indicação de que a espécie não encontrou na área condições adequadas para tal.
Subject(s)
Animals , Female , Male , Catfishes/physiology , Reproduction/physiology , Sexual Maturation/physiology , Brazil , Catfishes/anatomy & histology , Catfishes/classification , Seasons , Sex RatioABSTRACT
Sepia pharaonis is an important commercial species endemic to the tropical Indo-Pacific region. Despite its commercial significance, only few information on natural populations is available. This study was aimed to describe the aspects of size-composition, length-weight relationship, catch rates, seasonal recruitment and inter-cohort growth patterns of S. pharaonis population (Clade C), distributed along the Eastern Arabian Sea (South-West coast of India). For this, the Dorsal Mantle Length (DML) and weight of cuttlefishes was obtained from commercial trawl catches, from April 2002 to October 2006. Data was analyzed by normal length-weight methods such as von Bertalanffy. A total of 12 454 cuttlefishes, ranging in length from four to 41cm were analyzed. Size-composition patterns discriminated two pulses in recruitment to the fishery, discernible by a decrease in the monthly mean size of the population. The DMLs of the two seasonal cohorts were subjected to modalprogression analysis using the Bhattacharya’s method for the estimation of growth. The estimated parameters L∞ and K in von Bertalanffy Growth Function (VBGF) were used to model growth curves in length for the cohorts. The first cohort, (post-monsoon cohort) which supports the major fishery, was composed of mediumsized, fast growing individuals, whereas the second cohort (pre-monsoon cohort), comprised of slow growing and large-sized individuals. There were differential growth characteristics between the sexes and the life span was estimated at less than 2.3years for males and 2.1years for females. Negative allometric growth in weight (W) with length (L) was observed for males (W=0.33069.L2.5389) and females (W=0.32542.L2.6057). The females were heavier compared to males at any given mantle length, and the males were found to attain larger ultimate lengths. The major fishing season for cuttlefish was from May to November, when higher monthly catch rates of 1.67-13.02kg/h were observed in comparison with 0.03-0.85kg/h in December-April. Seasonal catch rates indicated a migratory life cycle of S. pharaonis between offshore and inshore coastal zones.
Sepia pharaonis es una importante especie endémica comercial del trópico Indo-Pacífico. A pesar de su valor comercial, hay muy poca información de sus poblaciones naturales disponible. En este estudio se describen aspectos como composición de tallas, relación longitud-peso, tasas de captura, reclutamiento estacional y patrones de crecimiento entre cohortes de la población (Clado C), distribuidos a lo largo del Mar Arábigo del Este (costa Suroeste de India). Se obtuvo la Longitud del Manto Dorsal (LMD) y el peso de las capturas de los arrastres comerciales, de Abril 2002 a Octubre 2006. Los datos fueron analizados mediante FiSAT y von Bertalanffy. Se capturó un total de 12 454 sepias, con una longitud entre 4-41cm. Los patrones de composición de tallas discriminaron dos pulsos en el reclutamiento de la pesquería, perceptibles por una disminución en el tamaño promedio mensual de la población. Los LMD de las dos cohortes estacionales se sometieron a un análisis de progresión modal mediante el método de Bhattacharya para la estimación del crecimiento. La primera cohorte (después de los monzones) mantiene la principal pesquería, se compone de individuos medianos de rápido crecimiento, mientras que el segundo grupo (pre-monzón) está compuesto por individuos de crecimiento lento y de gran tamaño. Se encontraron diferencias en las características de crecimiento entre sexos y la duración de vida útil se estima en menos de 2.3 años para machos y 2.1 años para hembras. Se observó crecimiento alométrico negativo entre el peso (W) y la longitud (L) para machos (W=0.33069. L2.5389) y hembras (W=0.32542.L2.6057). Las hembras fueron más pesadas en comparación con los machos en cualquier longitud de manto. La temporada de pesca más importante fue de mayo a noviembre, cuando se tuvieron las tasas de captura mensual más altas, de 1.67-13.02kg/h en comparación con 0.03-0.85kg/h entre diciembre y abril. Las tasas de captura estacional indican un ciclo de vida migratorio de S. pharaonis entre las zonas marinas y costeras de las áreas someras.
Subject(s)
Animals , Female , Male , Sepia/growth & development , Fisheries , India , Oceans and Seas , Population Dynamics , Seasons , Sex Factors , Sepia/anatomy & histology , Sepia/classificationABSTRACT
Nowadays, the successful management of small scale fisheries requires the use of biometric data collected in the field, in order to transform them into suitable indicators. The present study describes the lengthweight relationships for 36 freshwater fish species from two tropical reservoirs Ayame I and Buyo, in Côte d’Ivoire. The main objective of the study was to provide a length weight key for a wide range of freshwater fish species from these tropical reservoirs exploited by the inland fisheries. The samplings were carried out at Buyo from July 1997 to August 1998, and from August 2004 to July 2005 in Ayame I. Fish specimens were collected from catches of artisanal fisheries using gill-nets, cast-nets, beach seines and bamboo traps. After landings, samples were identified, total weight for each specimen was recorded to the nearest gram and standard length was measured to the nearest millimetre. A total of 12 724 individuals belonging to 15 families and 24 genera were obtained in this study. The results indicated that the family with the highest number of species was Cichlidae with eight species. Six families were recorded with only one species per family. The value of the exponent b in the length weight relationships (W=aLb) ranged from 2.173 for Marcusenius furcidens to 3.472 for Polypterus endlicheri and the median of b was 2.756. The modal value of the exponent b equal to 2.70 indicates that most of the fish species in Ayame I and Buyo Reservoirs have negative allometric growth. The length weight parameters of the three species, Lates niloticus, Synodontis koensis and S. punctifer are described for the first time in these regions. The present length-weight key for 36 freshwater fish species could be used as a valuable tool for fishery managers, in order to improve the inland fisheries statistics largely based on hydropower reservoirs in Côte d’Ivoire.
Hoy en día, el manejo exitoso de pesquerías a pequeña escala requiere el uso de datos biométricos recolectados en campo, y así poder transformarlos en indicadores apli- cables. El presente estudio describe la relación longitud-peso para 36 especies de peces de agua dulce encontrados en dos embalses hidroeléctricos tropicales en Ayame I y Buyo, en Costa de Marfil. El principal objetivo del estudio es proveer una clave de longitud-peso para una amplia variedad de peces de agua dulce provenientes de estos dos embalses, los cuales son explotados por pesquerías locales. El muestreo fue llevado a cabo en Buyo durante los meses de Julio 1997 a Agosto 1998, y en Ayame I de Agosto 2004 a Julio 2005. Los especímenes fueron tomados de trampas colocadas por pesqueros artesanales, utilizando redes de enmalle, atarraya, red de cerco y trampas de bambú. Los especímenes fueron identificados, pesados hasta el gramo más cercano y la longitud fue medida hasta el milímetro más cercano. Un total de 12 724 individuos pertenecientes a 15 familias y 24 géneros fueron obtenidos en este estudio. Los resultados muestran que la familia con más número de especies fue Cichlidae con 8 especies. En seis familias se obtuvo únicamente una especie. El valor del exponente b en la relación longitud-peso (w=al b) estuvo dentro del rango de 2.173 para Marcusenius furcidens, de 3.472 en Polypterus endlicheri, y la media de b fue 2.756. El valor modal del exponente b igual a 2.70 indica que la mayoría de especies de peces en las reservas Ayame I y Buyo tienen crecimiento alométrico negativo. Los parámetros longitud- peso de tres especies, Lates niloticus, Synodontis koensis and S. punctifer son descritos por primera vez en estas localidades. La clave longitud-peso presentada para 36 especies de peces puede ser utilizada como una herramien- ta valiosa para administradores pesqueros, y así mejorar ampliamente las estadísticas de las pesquerías basadas en embalses hidroeléctricos en Costa de Marfil.
Subject(s)
Animals , Body Weight , Fishes/anatomy & histology , Cote d'Ivoire , Fresh Water , Fishes/classificationABSTRACT
In this study, Arius maculatus were collected using the samples caught by bottom trawling off the southwestern coast of Taiwan. Length-weight and length-length, fork (FL), standard (SL) and total (TL) lengths, relationships were determined. The relationships between the lengths were all significantly linear (p<0.01), the b value in the length-weight relationship for this value was significantly lower than 3 in the fall (p<0.01), when the temporal changes were taken into account, indicating that only the sampling time affected the growth pattern of A. maculatus. The growth was isometric in the spring, summer and winter, but it was negative and allometric in the fall.
ABSTRACT
In this work the length-weight relationship and the condition factor of Astyanax intermedius parasitised and not by Paracymothoa astyanaxi were analysed in the Grande River. The length-weight relationship was estimated for females, males and immatures, and seasonally for the fishes and the parasites through the expression W = aLb. The condition factor of non-parasitised specimens differed seasonally and between sexes, contrasting with the results for parasitised fishes which showed no differences between sexes and season. The condition factor of non-parasitised specimens was higher than that of the parasitised fishes. Specimens of Astyanax intermedius parasitised do not have the same biotic conditions compared to non-parasitised individuals, in which the condition factor was similar over the years. In conclusion, parasitism by P. astyanaxi has deleterious effects on this host population which may cause changes in the reproductive and food dynamics of parasitised specimens due to low body conditions.
Foram analisados a relação peso-comprimento e o fator de condição de Astyanax intermedius parasitados ou não pelo isópode Paracymothoa astyanaxi. A relação peso-comprimento foi estimada para fêmeas, machos e imaturos, e sazonalmente tanto para os peixes quanto para o parasito, por meio da expressão P = aCb. O fator de condição dos exemplares não parasitados diferiu sazonalmente e entre os sexos, contrastando com os valores do fator de condição dos peixes parasitados, que não apresentaram diferenças sazonais e entre os sexos. O fator de condição dos exemplares não parasitados foi sempre maior do que o dos exemplares parasitados. Os exemplares de Astyanax intermedius parasitados não passaram pelas mesmas condições bióticas dos indivíduos não parasitados, apresentando um fator de condição semelhante ao longo do ano. Conclui-se que o parasitismo por P. astyanaxi atua de forma deletéria na população desse hospedeiro, podendo causar alterações nas dinâmicas reprodutiva e alimentar dos exemplares parasitados em razão da baixa condição corpórea.
Subject(s)
Animals , Female , Humans , Male , Crustacea , Characidae/parasitology , Brazil , Characidae/anatomy & histology , Characidae/classification , Crustacea/anatomy & histology , Crustacea/classification , Rivers , SeasonsABSTRACT
Length-weight and length-girth relationships (LWR and LGR), relative weight (Wr) and relative condition factor (Krel) of four commercial fish species (Lethrinus nebulosus, Carangoides talamparoides, Lutjanus argentimaculatus and Argyrops spinifer) from northern Persian Gulf (Bushehr coastal waters) were calculated. Samples were collected on monthly basis during December 2006 to June 2008 using pot nets. The LWR had a significant correlation for all species and the exponent b ranged from 2.6657 (L. nebulosus) to 2.8353 (L. argentimaculatus). All length-girth relationships also were highly significant and the exponent b ranged from 0.2776 (L. nebulosus) to 0.3591(A. spinifer). Relative weight ranged from 0.50±0.59 (C. talamparoides) to 1.02±1.35 (L. argentimaculatus). Relative condition factor also ranged from 1.01±0.17 (A. spinifer) to 1.05±0.5 (L. nebulosus). In conclusion, this study provides basic information for fishery biologists and managers in the Persian Gulf.
ABSTRACT
In order to describe some aspects of the population ecology of Bryconamericus stramineus in the Guiraí River basin, upper Paraná River basin, samples were taken bimonthly from October 2006 to August 2007 at seven sites in the basin. A total of 960 individuals, including 532 females, 316 males, and 112 of undetermined sex, were collected. A significant variation in the sex ratio was observed (Χ2 = 32.82; p < 0.001). Females were larger (59.7 mm) than males (58.9 mm); however, males showed a larger angular growth coefficient (b) than females. It was estimated that 50 percent of females were sexually mature at 36.4 mm. The highest rate of ovary development was observed in October, while in June 2007 no mature females were found. Mean fecundity was estimated at 313 eggs, and the relative fecundity was 184.6 eggs/g. The asymptotic was estimated at 62.8 mm and the growth rate at 0.76. The growth performance index was calculated at 3.47, the longevity at 3.94 years and the mortality (M) at 1.18 years. The recruitment pattern of the species showed peaks concentrated in periods of low rainfall.
Com o objetivo de descrever alguns aspectos populacionais e reprodutivos de Bryconamericus stramineus em riachos da bacia do rio Guiraí, Alto Rio Paraná, realizamos amostragens bimestrais de Outubro/2006 a Agosto/2007 em sete riachos da bacia. Foram coletados 960 indivíduos, sendo 532 fêmeas, 316 machos e 112 de sexo indeterminado. Constatamos variação significativa na proporção sexual (Χ² = 32,82; p < 0,001). As fêmeas foram maiores (59,7 mm) que os machos (58,9 mm); no entanto, os machos apresentaram maior coeficiente angular de crescimento (b). Estimamos que 50 por cento das fêmeas estão sexualmente maduras com 36,4 mm de comprimento padrão. As maiores frequências de fêmeas com ovários desenvolvidos foram observadas em Outubro, sendo que o único mês em que não foram encontradas fêmeas maduras foi Junho. A fecundidade media foi estimada em 313 ovócitos e a fecundidade relativa foi de 184,6 ovócitos/g. O comprimento assintótico foi estimado em 62,8 mm e a taxa de crescimento em 0,76. O índice de performance de crescimento foi calculado em 3,47, a longevidade em 3,94 anos e a mortalidade em 1,18. O padrão de recrutamento da espécie estudada apresentou picos concentrados no período de menor pluviosidade.
ABSTRACT
Se estimó la relación longitud-peso de Cachana (Cynopotamus atratoensis) en la ciénaga grande de Lorica entre enero 2000 y diciembre 2002. La relación longitud-peso fue: WT = 0,0028 (± 0,03) LT3,41 (± 0,02), r = 0,99, n = 2.671, con coeficiente de crecimiento alométrico positivo, que osciló entre 3,34 (2002) y 3,44 (2001), sin diferencias estadísticas significativas. El factor de condición osciló entre 0,0026 (2001) y 0,0034 (2002), sin diferencias estadísticas significativas, confirmándose la premisa de la relación inversa entre este parámetro y el coeficiente de crecimiento de la relación longitudpeso. Se encontró correlación entre el factor de condición, los niveles de la ciénaga grande de Lorica y la época de desove de Cachana y se infiere que sus proporciones corporales no variaron durante el período estudiado, adaptándose a las nuevas condiciones de la ciénaga.
The length-weight relationship of Cachana (Cynopotamus atratoensis) in the cienaga Grande de Lorica between January 2000 and December 2002 was estimate. The length- weight relationship was TW = 0.0028 (± 0.03) TL3,41 (± 0,02), r = 0,99, n = 2,671, with growth coefficient positive allometric, ranging between 3.38 (2000) and 3.44 (2001) without statistically significant differences. The condition factor ranged from 0.0026 (2001) and 0.0034 (2002), without statistically significant differences, confirming the premise of the inverse relationship between this parameter and the growth coefficient of length-weight relationship. There was a correlation between the condition factor, the levels of the cienaga Grande de Lorica and spawning season of the Cachana and it appears that its body proportions remained unchanged over the study period, adapting to new conditions of the cienaga.
ABSTRACT
Foram analisados a relação peso-comprimento e o fator de condição de Oligosarcus hepsetus no Rio Grande do Parque Estadual da Serra do Mar - Núcleo Santa Virgínia, São Paulo. A relação peso-comprimento foi estimada para imaturos, fêmeas e machos, através da expressão P = aCb. Os parâmetros a e b foram estimados após transformação logarítmica dos dados de peso e comprimento e subsequente ajuste de uma linha reta aos pontos pelo método dos mínimos quadrados. Para fêmeas e machos foram obtidas as equações da relação peso-comprimento por período do ano (outono, inverno, primavera e verão), utilizando o peso total e o peso sem as gônadas. O fator de condição dos imaturos foi mais alto do que para machos e fêmeas, possivelmente, devido ao gasto energético com o desenvolvimento dos ovócitos e em menor grau dos espermatozóides. Esta espécie apresentou maiores valores de fator de condição no outono devido ao acúmulo de gordura e nas demais estações estes valores diminuíram devido ao longo período reprodutivo. As condições ambientais da Mata Atlântica parecem ser primordiais para o desenvolvimento das estratégias reprodutivas apresentadas por Oligosarcus hepsetus.
In this work the length-weight relationship and the condition factor of Oligosarcus hepsetus were analyzed in the Grande river within the Santa Virgínia Unit of the Serra do Mar State Park, State of São Paulo. The length-weight relationship was esteemed for immature, females and male, through the expression W = aLb. The parameters a and b were dear after logarithmic transformation of the data of weight and length and subsequent adjustment of a straight line to the points for the method of the minimum square. For females and males were obtained the equations of the length-weight relationships by period of the year (autumn, winter, spring and summer), using the total weight and the weight without the gonads. The factor of condition of the immature was higher than for males and females, possibly, due to the energy expense with the development of the oocytes and in smaller degree of the spermatozoids. This species presented larger values of condition factor in the autumn due to the fat accumulation and in the other stations these values decreased due to the long reproductive period. The environment conditions of the Atlantic forest seem to be primordial for the development of the reproductive strategies presented by Oligosarcus hepsetus.
ABSTRACT
Age and growth parameters were estimated for bigeye tuna Thunnus obesus Lowe, 1839 sampled from China longline fisheries in the central Atlantic Ocean from October 2002 to July 2003 and from August 2004 to March 2005. The von Bertalanffy growth parameters were estimated at L8=217.9 cm fork length, k=0.23 year-1, and t0=-0.44 year. The total mortality rate (Z) was estimated to be from 0.82 to 1.02, the fishing mortality (F) and the natural mortality were 0.54 year-1 and 0.39 year-1, respectively. The exploitation ratio (E) was 0.35. This study provides the detailed estimates of growth and mortality rate for bigeye tuna in the central Atlantic Ocean, which can be used as biological input parameters in further stock evaluations in this region. However, age analysis, additional validation of the size composition and stock structure are needed for future studies. Rev. Biol. Trop. 57 (1-2): 79-88. Epub 2009 June 30.
Subject(s)
Animals , Female , Male , Mortality , Tuna/growth & development , Atlantic Ocean , China , Tuna/classificationABSTRACT
The structure of Cichla kelberi population was characterized regarding the sex ratio, total length composition and some reproductive characteristics. The specimens were collected in two periods, from November 2002 to November 2003 and from December 2004 to May 2006. The sex ratio was significantly different than 1:1. The total length varied from 3.4 to 40.1 cm, with individuals in the shortest length classes occurring throughout the year, but with greater incidence in the warmer periods. Females and males reached similar lengths and there was no difference between the sexes regarding the length-weight relationship. The estimated values of condition factor were near the central value of 1.0 and decreased during the cooler months, coinciding with periods of lower reproductive activity. Individuals with mature or semi-spent gonads occurred from November to April, indicating that Cichla kelberi reproduces for a long period of time. The spawning is partitioned, with an average absolute fecundity of 6072 oocytes (from 5220 to 6908 oocytes). The high relative condition factor values, long reproductive period, large output of fingerlings and high fecundity are biological conditions that indicate the species is well adapted in this reservoir.
A população de Cichla kelberi foi caracterizada quanto à proporção sexual, composição em comprimento total e algumas características reprodutivas. As coletas foram realizadas em dois períodos, de novembro de 2002 a novembro de 2003 e de dezembro de 2004 a maio de 2006. A proporção sexual foi significativamente diferente de 1:1. Os comprimentos totais variaram de 3,4 a 40,1 cm sendo que a ocorrência de indivíduos nas classes de menor comprimento se deu ao longo de todo o ano, com maior incidência nos períodos mais quentes. Fêmeas e machos atingem comprimentos similares e não houve diferença entre os sexos quanto à relação peso - comprimento. Os valores do fator de condição estimados foram próximos ao valor centralizador 1.0 e apresentaram quedas nos meses mais frios, coincidindo com períodos de menor atividade reprodutiva. Indivíduos com gônadas Maduras ou Semi Esgotadas ocorreram de setembro a abril, indicando que Cichla kelberi reproduz-se por um longo período. A desova é do tipo parcelada e apresenta, em média, uma fecundidade absoluta de 6072 ovócitos (de 5220 a 6908 ovócitos). Os altos valores de fator de condição relativo, longo período reprodutivo, grande produção de larvas e fecundidade alta são condições biológicas que indicam boa adaptação da espécie neste reservatório.
Subject(s)
Animals , Biodiversity , Species Specificity , Fertility , Oocytes , Perciformes/classification , Perciformes/growth & developmentABSTRACT
Length-weight relationship (LWR), condition factor (K) and stomach content of three cichlid fishes (Hemichromis bimaculatus, Sarotherodon melanotheron, and Chromidotilapia guentheri) were calculated at Eleiyele reservoir, Nigeria, Africa. The fish were collected monthly from fishermen during the dry season (January-March 2001) and the rainy season (April, May, June 2001). Gill nets of mesh sizes 50-55 mm were used. The LWR had a significant correlation for the three species and the growth exponent (b) for H. bimaculatus indicates a negative allometric growth (S. melanotheron and C. guentheri had isometric growth). Condition factor values were higher than one in the three species, and varied with size and season. Stomach contents revealed that the three species are omnivorous and that diet composition varies seasonally. Rev. Biol. Trop. 55 (3-4): 969-977. Epub 2007 December, 28.
Se investigó la relación de peso-longitud (LWR), factor de condición (K) y contenidos estomacales de tres peces cíclidos (Hemichromis bimaculatus, Sarotherodon melanotheron y Chromidotilapia guentheri) en la reserva de Eleiyele, Nigeria, África. El LWR muestra una correlación significativa para las tres especies y el crecimiento exponencial (b) indica que H. Bimaculatus tiene crecimiento alométrico negativo, mientras S. melanotheron y C. guentheri tienen un crecimiento alométrico isométrico. El factor de condición para las tres especies fue mayor a uno, y varía con el tamaño y la época. El análisis de los contenidos estomacales reveló que las tres especies son omnívoras, variando la composición relativa de cada tipo de alimento con la estación del año.
Subject(s)
Animals , Cichlids/anatomy & histology , Biometry , Body Weight , Cichlids/classification , Cichlids/physiology , Feeding Behavior/physiology , Gastrointestinal Contents , Nigeria , SeasonsABSTRACT
Este trabalho usa dados de lagartas da borboleta neotropical Hypothyris ninonia daeta (Bdv.) (Nymphalidae: Ithomiinae) para demonstrar que medidas do comprimento do corpo podem ser empregadas como índice acurado do peso em estudos de crescimento larval. Também determina analiticamente o intervalo de tempo entre medições consecutivas para manter em níveis aceitáveis as chances de sobreposição nas estimativas (i.e., as chances de que lagartas de comprimentos diferentes tenham o mesmo peso). Os resultados mostram que o estudo do crescimento de insetos imaturos não é necessariamente um empreendimento restrito ao laboratório. Esse enfoque pode ser particularmente útil para estimar a taxa de crescimento de imaturos no campo, quando medidas mais acuradas não são possíveis ou mesmo desejáveis de se obter.
This work utilizes data for caterpillars of the Neotropical butterfly Hypothyris ninonia daeta (Bdv.) (Nymphalidae: Ithomiinae) to demonstrate that body length measurements can be used as an accurate index of weight in larval growth studies. It also determines analytically the time interval that must be maintained between consecutive measurements in order to keep within acceptable levels the chances of overlap in estimates (i.e., the chances that caterpillars of different lengths have the same weight). These results show that studying the growth of immature insects is not necessarily an exclusive laboratory enterprise. This approach may be particularly useful to estimate immature growth rate in the field, when more accurate measures are not possible or even desirable to obtain.