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Sample records for chirostoma humboldtianum atheriniformes

  1. Oocyte structure and ultrastructure in the Mexican silverside fish Chirostoma humboldtianum (Atheriniformes: Atherinopsidae

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    Rodolfo Cárdenas

    2008-12-01

    Full Text Available the structural and ultrastructural features of gonads from endemic Mexican fish have received scarce attention. This study describes the histological and ultrastructural characteristics of the oocyte in Chirostoma humboldtianum. The ovary is asynchronic, and as such, most phases of oocyte development are found in the same ovary. The complete process of oogenesis was divided in five stages: oogonium and folliculogenesis, primary growth, cortical alveoli and lipid inclusions, vitellogenesis and maturation. The presence of big filaments, which appear at the end of primary growth, induces some common follicular adaptation. During primary growth, abundant ribosomes, rough endoplasmic reticulum, and mitochondria are grouped in the cytoplasm. At the end of this stage, the Z1 layer of the chorion is developed, while microvilli start to be evident as well. In the cortical alveoli and lipid droplets phase, intense PAS positive vesicles, some of them containing nucleoid material, are observed in the peripheral cytoplasm and the lipid droplets take a more central position. In vitellogenesis, the proteic yolk accumulates in a centripetal way while the chorion is completely formed. In maturation, the germinal vesicle migrates to the animal pole, meiosis is restored, and there is nuclear breakdown. The oocyte increases its size and holds some oil droplets and a big fluid mass of yolk. On the outside, filaments surround the oocyte completely. Rev. Biol. Trop. 56 (4: 1825-1835. Epub 2008 December 12.Los aspectos estructurales y ultraestructrurales de las gónadas de peces mexicanos endémicos han sido poco estudiados. En el presente trabajo reportamos las características histológicas y ultraestructurales del ovocito de Chirostoma hulmboldtianum. El ovario es de tipo asincrónico, por ende, la mayoría de las fases del desarrollo del ovocito pueden ser encontradas en el mismo ovario. El desarrollo del ovocito fue dividido en cinco etapas: ovo-gonia y foliculog

  2. Alimentación de Chirostoma humboldtianum (Valenciennes; (Pisces: atherinopsidae en el estanque JC en Soyaniquilpan, Estado de México

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    G. Elías Fernández

    2008-01-01

    Full Text Available Los charales son peces endémicos del centro de México que han sido consumidos desde épocas prehispánicas, en la actualidad, el volumen de su captura ha disminuido por diversos motivos como la sobrepesca y la contaminación del hábitat, por lo cual es muy importante estudiar las poblaciones que quedan para conocer sus requerimientos ecológicos y alimenticios y poder plantear alternativas para su conservación. Por lo anterior, los objetivos de este trabajo fueron: determinar los grupos alimenticios que consume Chirostoma humboldtianum en el estanque JC en Soyaniquilpan, Estado de México y la variación de algunos parámetros físicos y químicos del agua. Se realizaron seis muestreos mensuales de diciembre de 2001 a mayo de 2002. Se registró la temperatura, la profundidad, la transparencia, la conductividad, la turbiedad, el pH, el oxígeno disuelto, la dureza y la alcalinidad. Los peces se capturaron con un chinchorro de 25 metros de longitud y 8 mm de abertura y fueron fijados con formalina al 10 %. El contenido alimenticio fue identificado con claves especializadas. Para determinar el porcentaje de los grupos alimenticios se utilizó el método volumétrico y de frecuencias. Se encontró que el agua es templada, turbia, con regular cantidad de oxígeno disuelto, de dureza moderada. Chirostoma humboldtianum consumió 21 tipos de organismos, destacando Keratella, Trichocerca, Asplanchna, Bosmina, además de copépodos, coríxidos y quironómidos. El método de frecuencias mostró a Cyclops y Keratella como el alimento preferencial.

  3. A fourth teleost lineage possessing extra-oral teeth: the genus atherion (teleostei; atheriniformes).

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    Sire, J Y; Allizard, F

    2001-12-01

    In the course of an evolutionary and developmental study on the dermal skeleton, our attention was drawn to the existence of denticles located outside the oral cavity in the atheriniform species Atherion elymus. These denticles, attached to the surface of most dermal bones of the head, are especially numerous on the snout, chin and the undersides of the lower region of the head, where they are aligned forming a crenulated keel. Using light, scanning and transmission electron microscopy, we clearly demonstrate the dental (vs bony) nature of these denticles. They are small, conical elements mostly oriented backwards and are not ankylosed to the bone support. Ligaments originating from the internal and external surface of the base of the dentine cone link the denticles to the attachment bone, which itself merges with the bone support below. The denticles have the same form and structure as teeth, from which they differ only in having a larger base and a pulp cavity that is nearly completely filled with secondary dentine by centripetal deposition. This suggests that the denticles have a longer functional history than teeth. Atherion is now the fourth teleost lineage found to develop such denticles on the head.

  4. Estado De México

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    M. Á. Yubi Armendáriz

    2008-01-01

    Full Text Available Las relaciones de los organismos en la naturaleza se basan en dos ciclos, uno de materia y el otro de energía, dichos ciclos dan origen a las cadenas tróficas las cuales dan origen a los tres niveles tróficos; autótrofos, herbívoros y carnívoros. Para el caso de los peces de agua dulce, los organismos jóvenes viven y se alimentan en la orilla y superficie del agua, para conocer lo que comen se analiza el tracto digestivo. Por lo cual el presente trabajo pretende determinar la trama trófica de los peces del embalse San Miguel Arco. Se capturaron los peces del embalse con un chinchorro de 30 metros de largo y 1/3 de pulgada, los organismos se fijaron con formalina al 10 %, los peces se identificaron al igual que el alimento que consumieron, con claves especializadas, a la abundancia de los grupos alimenticios se les aplicó el índice de Simpson. Se encontró que Chirostoma humboldtianum, es zooplanctófago especialista, Cyprinus carpio, y Carassius auratus son planctófagos generalistas y Poeciliopsis infans es planctófago especialista. La trama trófica se basa en zooplancton (Bosmina y Mastigodiaptomus además de zoobentos (Corixidae.

  5. Selectividad del zooplancton y solapamiento trófico entre tallas del pez Menidia humboldtiana (Atheriniformes: Atherinopsidae en el embalse Danxhó, México

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    Regina Sánchez Merino

    2009-06-01

    Full Text Available El charal Menidia humboldtiana es considerado como una de las especies de gran importancia en la industria pesquera de algunos estados de México. Es necesario conocer el efecto que esta especie ejerce sobre su alimento para saber si seleccionan las presas de mayor talla, si hay competencia por el alimento entre especies nativas e introducidas, y para comprender el comportamiento del zooplancton ante peces zooplanctófagos. Se determinó si M. humboldtiana selecciona su alimento, sobre qué géneros lo hace, y si existe traslape en la dieta entre las diferentes tallas. Los peces se recolectaron por medio de un chinchorro de 88 mm de abertura de malla, en seis estaciones de muestreo durante un año, en el embalse Danxhó, y una muestra de zooplancton fue recolectada por filtrado con una red de 125 µm. El análisis de los contenidos estomacales se realizó en peces agrupados en intervalos de longitud estándar para cada época del año, por medio del método volumétrico. Para evaluar el traslape trófico entre los diferentes intervalos de longitud, se utilizó el índice de Morisita modificado por Horn. El zooplancton estuvo representado por doce géneros: Mastigodiaptomus y Cyclops (Copepoda; Bosmina, Diaphanosoma, Daphnia, Ceriodaphnia, Moina, Alonopsis y Camptocercus (Cladocera; Asplanchna, Conochillus y Filinia (Rotifera. Durante la primavera, los charales de 3-8.9 cm presentaron un marcado traslape, para el verano fueron los grandes (7-10.9 cm, en otoño el traslape fue en todas las tallas, y en invierno solo las tallas intermedias (5-8.9 cm lo presentaron.Selectivity of zooplankton and trophic overlap between size Menidia humboldtiana fish (Atheriniformes: Atherinopsidae in the reservoir Danxhó, Mexico. The Menidia humboldtiana silverside is considered one of the most important species in fisheries in some states of Mexico. Knowing the choice that this species exercises over its food gives us an understanding of the behavior of

  6. Trematodiasis en algunos peces del lago de Cuitzeo, Michoacán, México

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    Ma. del Carmen Guzmán-Cornejo

    1999-09-01

    Full Text Available In September, 1995 and January, 1996, six species of fishes from Lake Cuitzeo, Michoacan, Mexico, were collected (Alloophorus robustus n=30, Goodea atripinnis n=30, Xenotoca variata n=41, Chirostoma jordani n=30, Carassius auratus n=30 and Oreochromis aureus n=30, to establish the infection levels reached by Posthodiplostomum minimum, Clinostomum complanatum and Diplostomum (Tylodelphys sp., in their hosts. Infection caused by P. minimum metacercariae was the most important helminthiasis considering the number of hosts they parasite (five of six, and the high levels of abundance of the infection; we suggest that fish preferences and the generalist character of the trematode are the causes that determine this infection. Finally, the role of goodeids and atherinids in transmission of infections in the lake is confirmed; the former being the main group mantaining such infections.

  7. Modelos nulos en interacciones biológicas, una propuesta: depredación en chirostoma riojai-zooplancton

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    Octavio M. Vilchis

    2000-01-01

    Full Text Available Se muestra una propuesta de construcción rápida y confiable de los modelos, a partir de una prueba de bondad de ajuste y una de "G" con el fin de apreciar diferencias significativas. Se analiza un estudio de caso que presenta un patrón ecológico (depredación conocido, entre un pez y sus presas.

  8. Growth hormone-insuline-like growth factor-I system in pejerrey Odontesthes bonariensis (Atheriniformes

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    S.E. Arranz

    2008-07-01

    Full Text Available Using biotechnology to increase the growth rates of fish is likely to reduce production costs per unit of food. Among vertebrates, fish appear to occupy a unique position, when growth patterns are considered. With few exceptions, fish species tend to grow indeterminately, implying that size is never fixed. Both hyperplasia and hypertrophy contribute to post-larval muscle growth in fish. Growth hormone (GH - Insulin-like Growth Factor I (IGF-I is the most important growth axis in fish. Our experimental model, the pejerrey, Odontesthes bonariensis (Ateriniformes is a South American inland water fish considered to be a promising species for intensive aquaculture. However, one major drawback to achieve this goal is its slow growth in captivity. In order to understand how growth is regulated in this species, our first objective was to characterized pejerrey GH- IGF-I axis. We first cloned and characterized pejerrey (pj GH, IGF-I and the growth hormone receptors (GHRs I and II. In addition to providing valuable data for evolutionary comparison of GH, investigation of GH action in teleosts is particularly important because of its potential application in aquaculture. GH can not only promote the somatic growth in fish but also lower dietary protein requirements. A prerequisite for providing sufficient amounts of GH for basic research and aquaculture application is a large-scale production of GH. For that purpose, recombinant pjGH was expressed in a bacterial system. Protocols for solubilization and proper folding were achieved. Activity of recombinant pjGH was assessed in fish by measuring the liver IGF-I response to different doses of GH. IGF-I transcript was measured in the liver after pjGHr in vivo stimulation by means of quantitative real-time PCR assays. A dose-dependent response of IGF-I mRNA was observed after pjGHr administration, and reached a 6 fold IGF-I maximum increase over control group when 2.5 µg pjGH /g-body weight were injected. Temporal analysis of hepatic IGF-I mRNA levels showed that administration of a single dose of pjGHr into juvenile pejerrey resulted in a significant increase (P<0.02 9 hours post injection. These results demonstrates that recombinant pjGH could promote a dramatic response in liver, increasing the IGF-I mRNA level. We also study the effect of GH on muscle growth after oral administration. A significant association between GH doses and mean fiber area (MFA was observed even with a caloric restrictive diet. MFA increased 3.7 µm² per each unit of GH supplied indicating that GH promoted white muscle hypertrophy. These preliminary data indicates that GH could be absorbed by the intestine in an active form and promote somatic growth.

  9. [Evaluation of ten fish species to be included as part of renal diet, due to their protein, phosphorus and fatty acids content].

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    Castro-González, Maria Isabel; Maafs-Rodríguez, Ana Gabriela; Pérez-Gil Romo, Fernando

    2012-06-01

    Because renal disease is highly complex, its nutritional treatment is complicated and many foods are restricted, including fish because its phosphorus content. The aim of the present study was to analyze ten fillet fish species, commonly consumed in Mexico (Cyprinus carpio carpio, Ophichthus rex, Symphurus elongatus, Eucinostomus entomelas, Chirostoma patzcuaro, Bairdiella chrysoura, Salmo salar Oreochromis urolepis hornorum, Sphyraena guachancho, Istiophorus albicans), to determine their phosphorus (P), protein (Pr), cholesterol, sodium, potassium, vitamins D3 and E, and n-3 PUFA (EPA+DHA) according to the AOAC techniques, in order to identify which species could be included in renal diet; particularly because of their risk:benefit relations (calculated with those results). Protein values ranged from 16.5 to 33.5g/100 g of fillet; the specie with the highest phosphorus contest was Salmo salar, and with the lowest, Symphurus elongatus. EPA+DHA quantity ranged from 79.64 mg/100 g to 1,381.53 mg/100 g. Considering de P/Pr relation recommended to renal patients, all analyzed species (except Salmo salar, Ophichthus rex and Istiophorus albicans) could be included in their diet. As for the P/EPA+DHA relation, the species most recommended to renal patients are Symphurus elongatus, Bairdiella chrysoura and Sphyraena guachancho.

  10. The occurrence of the Flying Fish, Hirundichthys speculiger (Valenciennes, 1847), in the North Sea (Pisces, Atheriniformes, Exocoetidae)

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    Boer, P.; Nijssen, H.

    1972-01-01

    The occurrence of a specimen of the Flying Fish Hirundichthys speculiger (Valenciennes, 1847) in the North Sea is recorded. This is the first record of a member of the family Exocoetidae in the coastal waters of the Netherlands. The specimen is illustrated, and its occurrence in the North Sea is

  11. Uso do manguezal de Guaratiba, Baía de Sepetiba, Rio de Janeiro, pelo peixe-rei Atherinella brasiliensis (Quoy & Gaimard (Atheriniformes, Atherinopsidae The use of the Guaratiba magrove, Sepetiba Bay, Rio de Janeiro, by the silverside Atherinella brasiliensis (Quoy & Gaimard (Atheriniformes, Atherinopsidae

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    Leonardo M. Neves

    2006-06-01

    Full Text Available Coletas padronizadas de peixes e tomadas de variáveis ambientais foram realizadas em uma região de mangue na Baía de Sepetiba visando avaliar o papel deste sistema no ciclo de vida do peixe-rei Atherinella brasiliensis (Quoy & Gaimard, 1824. Um programa de amostragens mensais de arrastos de praia foi realizado, em cinco locais em uma área de mangue, entre agosto de 2002 e julho de 2003 nos períodos diurno e noturno, com variáveis ambientais tendo sido tomadas em cada local. As maiores abundâncias numéricas foram registradas no local da zona intermediária do canal principal, e as menores no local mais interno. As maiores contribuições em peso ocorreram no local mais externo e próximo da conexão com o mar. A abundância numérica foi diretamente correlacionada com a temperatura e salinidade, e o peso, com a salinidade e oxigênio dissolvido (p Fish and environmental variables were sampled in a mangrove area from Sepetiba bay to assess the role of this system in life cycle of the silverside Atherinella brasiliensis (Quoy & Gaimard, 1824. Standardized monthly sampling using beach seines were conducted at five sites, between August, 2002 and July, 2003 in daily (day/night basis, with environmental variables being taken at each site. The highest numerical abundance was recorded in the intermediate sample area in the mangrove channel and the lowest in the innermost site. The highest weight occurred in the outermost site near to the sea connection. Numerical abundance was directly correlated with temperature and salinity, and weight with salinity and dissolved oxygen (p < 0.05. Size ranged from 10 to 160 mm TL, with modes of 40-50 mm TL occurring all over the year in all sites. Recruitment occurred all year round but peaks (TL = 30 mm in October-December, 2002 and July, 2003 were recorded afterwards the records of larger fishes (September, 2002 and June, 2003 mainly in the outermost site. The largest fishes concentrated in the sandy substrate of the outermost sites, areas more suitable for A. brasiliensis spawning, with recruits dispersing all over the mangrove areas, which are used as rearing grounds. The affinity for highly structured habitats in mangrove and the capacity to use efficiently semi-closed systems was confirmed for A. brasiliensis in Guaratiba mangrove.

  12. Recrutamento do peixe-rei, Atherinella brasiliensis (Quoy & Gaimard (Atheriniformes, Atherinopsidae, na margem continental da Baía de Sepetiba, Rio de Janeiro, Brasil Recruitament of the silverside, Atherinella brasiliensis (Quoy & Gaimard (Atheriniformes, Atherinopsidae, in continental margin of Sepetiba Bay, Rio de Janeiro, Brazil

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    André Luiz Machado Pessanha

    2001-12-01

    Full Text Available The silverside, Atherinella brasiliensis (Quoy & Gaimard, 1824, a resident species of the shallows of bays, estuaries and coastal lagoons, was studied during two annual cycles, using beach seines (July 1996 to June 1998, in the continental margin of the Sepetiba Bay, aiming to assess recruitment and distribution patterns. A wide recruitment period, with young-of-the-year appearing from early spring to early autumn, was shown, with peaks of juveniles (Total Length-LT = 10-30 mm being recorded in two periods of the year; one in November and another in March. The highest abundances, of both juvenile and adults, were recorded in Coroa Grande and Itacuruçá, sites located in the outer Bay, during the whole summer, with significant differences were found. In spite of not having been found any statistically significant relationship between the environmental factors and the occurrence of this species, a trend of higher abundance in colder and more saline waters was detected. High values of growth coefficient (K = 0.93 and low asymptotic lenght (L∞ = 11.6 cm indicated that this species shows a high growth rate and short life cycle, with life span of 3.09 years, in this system.

  13. Estrutura populacional de Poecilia vivípara Bloch & Schneider, 1801 (Atheriniformes, Poeciliidae do rio Ceará-Mirim - Rio Grande do Norte Populational structure of Poecilia vivipara Block & Schneider, 1801 (Atheriniformes, Poeciliidae of Ceará-Mirim river, State of Rio Grande do Norte

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    Renata Swany Soares Nascimento

    2000-05-01

    Full Text Available Com o propósito de elucidar aspectos da estrutura populacional de Poecilia vivipara do rio Ceará-Mirim, município de Poço Branco, Rio Grande do Norte, foram capturados 3.390 exemplares em coletas mensais, no período de junho de 1995 a maio de 1997, utilizando-se tarrafas e peneiras. A partir dos resultados obtidos, constatou-se que as fêmeas, em relação aos machos, predominaram na proporção de 8:1, considerando-se as análises total e sazonal. No que se refere à distribuição por classes de comprimento para os sexos separados, observou-se uma maior amplitude de comprimento das fêmeas em relação aos machos e ainda uma ausência de diferenças entre as estações chuvosa e seca. De acordo com os valores obtidos para o &Teta; (3,86, verificou-se, para a espécie, um crescimento do tipo alométrico positivo. Quanto à influência dos fatores abióticos, fotoperíodo, pluviosidade, temperatura e nível do rio, relacionados aos aspectos da estrutura populacional, não foram verificados resultados significativos que a confirmassemWith the aim of clarifying aspects of the populational structure of Poecilia vivipara in the Ceará-Mirim river, State of Rio Grande do Norte, a total of 3,390 specimens were captured in monthly collections June 1995 trough May 1997, using nets and sieves. Results showed that females, prevailed in the proportion of 8:1, in the whole period as well as seasonaly. The total length classes distribution for separate sexes indicated that females reaches greatest lengths than males with no difference between dry and rainy seasons. The species growth is of the alometric positive type as suggested by the &Teta; value (3,86. No correlation between abiotic factors (photoperiod duration, rainfall, temperature and river water level and the population structure was found

  14. Hábito alimentar e osteologia da boca do peixe-rei, Odontesthes humensis de Buen (Atheriniformes, Atherinopsidae na Lagoa Mirim, Rio Grande do Sul, Brasil Feeding habits and mouth osteology of silverside, Odontesthes humensis de Buen (Atheriniformes, Atherinopsidae in the Mirim Lagoon, Rio Grande do Sul, Brazil

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    Fábio Lameiro Rodrigues

    2001-09-01

    Full Text Available Gut contents of 304 individuals of the silverside Odontesthes humensis de Buen, 1953 were analyzed using frequency of occurrence (FO% and gravimetric (P% methods. A total of 207 individuals (68.1% had some food itens in the gut, while 97 individuals (31.9% had empty guts. The silverside Odontesthes humensis has presented a benthic carnivorous diet, preying mainly on molluscs and arthropods. The molluscs Heleobia sp. (FO = 61.35% and Corbicula fluminea (Müller, 1774 (FO = 57.97% were the most frequent itens, followed by Neocorbicula limosa (Maton, 1811 (FO = 17.39%. Among the arthropods, the coleoptera insects (FO= 18.84% were dominant followed by, insect larvae (FO = 6.76%, the crustacean Palaemonetes argentinus Nobili, 1901 (FO = 1.93% and isopods (FO = 1.45%. Vegetal remains, organic matter and digested fish were grouped due to low frequency (FO = 9.13% being considered occasional. Juvenile fed mainly on insect larvae and moluscs, while the adults preferred molluscs and coleoptera. On the description of its feeding apparatus the importance of a protrusible upper jaw was observed, being important on the capture of prey in inaccessible places. A protrusible mouth and the format of the pharingean plates, are important morphological characters that assist on the capture and handling of prey. The molariform shaped pharingean teeth help break hard food items, as shells and carapaces.

  15. Lunar Impact Basins: Stratigraphy, Sequence and Ages from Superposed Impact Crater Populations Measured from Lunar Orbiter Laser Altimeter (LOLA) Data

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    Fassett, C. I.; Head, J. W.; Kadish, S. J.; Mazarico, E.; Neumann, G. A.; Smith, D. E.; Zuber, M. T.

    2012-01-01

    Impact basin formation is a fundamental process in the evolution of the Moon and records the history of impactors in the early solar system. In order to assess the stratigraphy, sequence, and ages of impact basins and the impactor population as a function of time, we have used topography from the Lunar Orbiter Laser Altimeter (LOLA) on the Lunar Reconnaissance Orbiter (LRO) to measure the superposed impact crater size-frequency distributions for 30 lunar basins (D = 300 km). These data generally support the widely used Wilhelms sequence of lunar basins, although we find significantly higher densities of superposed craters on many lunar basins than derived by Wilhelms (50% higher densities). Our data also provide new insight into the timing of the transition between distinct crater populations characteristic of ancient and young lunar terrains. The transition from a lunar impact flux dominated by Population 1 to Population 2 occurred before the mid-Nectarian. This is before the end of the period of rapid cratering, and potentially before the end of the hypothesized Late Heavy Bombardment. LOLA-derived crater densities also suggest that many Pre-Nectarian basins, such as South Pole-Aitken, have been cratered to saturation equilibrium. Finally, both crater counts and stratigraphic observations based on LOLA data are applicable to specific basin stratigraphic problems of interest; for example, using these data, we suggest that Serenitatis is older than Nectaris, and Humboldtianum is younger than Crisium. Sample return missions to specific basins can anchor these measurements to a Pre-Imbrian absolute chronology.

  16. Dieta, selectividad y solapamiento trófico entre las tallas del pez blanco Menidia humboldtiana (Atheriniformes: Atherinopsidae en el embalse Tiacaque, México

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    Regina Sánchez

    2013-06-01

    Full Text Available Menidia humboldtiana es una especie nativa muy apreciada por su delicado sabor. Se determinó el espectro trófico, selectividad y solapamiento trófico de ésta, durante 1995 (épocas del año, se obtuvieron muestras de zooplancton e identificaron a nivel genérico. Los peces capturados se agruparon en intervalos de longitud estándar para cada época. Se analizaron los contenidos estomacales (método volumétrico, Laevastu, selectividad (Chesson y solapamiento trófico (Morisita. Se registraron 14 géneros de zooplancton; Bosmina el más abundante (29 625ind/10L seguido por Cyclops (9 496ind/10L ambos en primavera. Los peces pequeños (1-4.9cm consumen a Cyclops en altos porcentajes en primavera e invierno, 61.24-69.82% respectivamente. Ceriodaphnia es consumida por peces de 3-10.9cm y de 13-14.9cm con 72.41-95.5% en verano; en otoño las tallas pequeñas ingieren a Mastigodiaptomus y Ceriodaphnia; Daphnia y Bosmina por peces de 5-8.9cm y los más grandes (9-14.9cm a Ceriodaphnia. M. humboldtiana realiza una depredación selectiva por Ceriodaphnia, Daphnia, Mastigodiaptomus, Bosmina y Cyclops. El solapamiento trófico fue muy marcado entre todas las tallas en primavera, otoño e invierno, a diferencia en verano los peces de 1-2.9 y 11-12.9cm no registraron un solapamiento con otros intervalos de longitud. M. humboldtiana es una especie zooplanctófaga, que realiza una depredación selectiva y un marcado solapamiento trófico entre los intervalos de longitud.

  17. Desarrollo de la sagitta en juveniles y adultos de Odontesthes argentinensis (Valenciennes, 1835 y O. bonariensis (Valenciennes, 1835 de la provincia de Buenos Aires, Argentina (Teleostei: Atheriniformes Development of the sagitta in young and adults of Odontesthes argentinensis (Valenciennes, 1835 and Odontesthes bonariensis (Valenciennes, 1835 from Buenos Aires province, Argentina (Teleostei: Atheriniformes

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    ANDREA D TOMBARI

    2005-12-01

    Full Text Available Se describió el desarrollo del otolito Sagitta de juveniles y adultos de Odontesthes argentinensis procedentes de Punta Rasa (36°22' S y Miramar (38°16' S y de Odontesthes bonariensis de la Laguna de Chascomús (35° 36' S. Se estudió, la morfología de las sagittae de ambas especies, analizando cuatro grupos morfológicos para O. argentinensis (I: 75-120 mm, II: 130-220 mm, III: 230-270 y IV: 280-320 mm y tres grupos morfológicos para O. bonariensis (I: 80-120 mm, II: 130-220 y III: 230-320 mm. Las características morfológicas comunes a la sagitta, de ambas especies, en los grupos estudiados son: presencia de sulcus, depresión areal dorsal en la cara medial, cara lateral con estrías y la presencia de un punto culminante en el borde dorsal. En la sagitta de O. argentinensis, la depresión areal dorsal se inicia ligada a la cauda, característica que permitió distinguir claramente entre otolitos de juveniles de ambas especies. A partir del estado adulto, la depresión areal dorsal se halla separada de la cauda en las dos especies y el análisis estadístico evidenció un crecimiento discontinuo. Se hallaron diferencias morfológicas entre pares de sagitta de un mismo individuo en cuanto a la forma del ostium, presencia de cisura, rostro y punto culminante, aunque no se halló significancia morfométricaThe development of the otolith sagitta was described in young and adults of two silverside species. Odontesthes argentinensis was collected from Punta Rasa (36°22' S and Miramar (38°16' S and, Odontesthes bonariensis collected from Laguna de Chascomús (35°36' S. Sagitta morphology was studied in both species, analyzing four morphological groups of O. argentinensis (I: 75-120 mm, II: 130-220 mm, III: 230-270 mm and IV: 280-320 mm and three morphological groups of O. bonariensis (I: 80-120 mm, II: 130-220 mm and III: 230-320 mm. The morphological features of the sagitta shared by both species are: sulcus present, dorsal areal depression on the medial face, lateral face with striations and the presence of the culminant point on the dorsal margin. The dorsal areal depression of O. argentinensis begins in contact with the cauda. This feature easily identifies the sagittae of young in both species. The dorsal areal depression is separated from the cauda in adults of both species, and the statistical analysis showed a discontinuous growth. Morphological differences were found between pairs of sagittae of the same specimen relating to the shape of the ostium, presence of an anterior excisure, rostrum and the culminant point, but no significant morphometric difference was found

  18. İzmir Körfezi İhtiyoplanktonu (1974-2005 Türleri.

    Directory of Open Access Journals (Sweden)

    Tülin Çoker

    2015-12-01

    Full Text Available İzmir Körfezi Türkiye Denizleri içinde ihtiyoplankton (balık yumurta larva incelemeleri açısından en yoğun çalışılmış körfezdir. İlk ayrıntılı çalışma 1974 yılında başlamış olup, 2005 yılında bu çalışmalar halen devam etmektedir. Saptanabilen türlerin yumurta, prelarva ve postlarval dönemleri ile ilgili tespitler körfez bölümlerine göre dağılımları boyları verilerek belirtilmiş, böylelikle çeşitli çalışmalar sonucu belirlenen toplam tür çeşitliliği ve türlerin körfez bölümlerine göre dağılımları ortaya konmuştur. Körfezde 1974-2005 yılları arasında toplam; 15 ordoya ait 186 (ordo, fam, tür düzeyinde yumurta, prelarva ve postlarva örneklenmiş; 2 ordo, 7 familya, 17 genus, 144 tür düzeyinde toplam 170 ilk kayıt verilmiştir. İzmir Körfezi ihtiyoplanktonu 48 familya ile temsil edilmiştir; Anguilliformes (Congridae, Nettastomiidae, Clupeiformes (Clupeidae, Engraulidae, Stomiiformes (Sternoptychidae, Photichthyidae, Stomiidae, Synodontidae, Aulophiformes (Paralepididae, Myctophiformes (Myctophidae, Lampridiformes (Regalecidae, Merlucciidae, Gadidae, Ophidiiformes (Ophiididae, Carapidae, Lophiiformes (Lophiidae, Atheriniformes (Atherinidae,Cyprinodontiformes (Belonidae, Syngnathiformes (Syngnathidae, Scorpaeniformes (Scorpaenidae, Triglidae, Percomorphı (Moronidae, Serranidae, Carangidae, Pomatomidae, Coryphaenidae, Sparidae, Centracanthidae, Sciaenidae, Mullidae, Cepolidae, Mugilidae, Labridae, Ammodytidae, Trachinidae, Uranoscopidae, Tripterygiidae, Blenniidae, Callionymidae, Gobiidae, Sphyraenidae, Trichiuridae, Scombridae, Centrolophidae, Pleuronectiformes (Scophthalmidae, Bothidae, Pleuronectidae, Soleidae. İç Körfez (6 ordo, 19 familya, Orta Körfez (8 ordo, 25 familya, Dış Körfez I (8 ordo, 30 familya, Dış Körfez II (8 ordo, 30 familya, Dış Körfez III’de (11 ordo, 39 familya’ya ait türler belirlenmiştir