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  • Springer  (3)
  • INVEMAR - Santa Marta, Colombia  (1)
Document type
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  • 1
    Electronic Resource
    Electronic Resource
    Relation of RNA/DNA ratios to growth for the scallop Euvola (Pecten) ziczac in suspended culture (1996)
    Springer
    Marine biology 126 (1996), S. 245-251 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We examined the relation of RNA/DNA ratios to growth for three size groups of the tropical scallop Euvola ziczac maintained in suspended culture at 8, 21 and 34 m in depth in the Golfo de Cariaco, Venezuel. Various growth parameters indicated that production decreased with depth. This was more likely due to a decrease in seston quality with depth than to temperatures or seston abundance (which were similar at the various depths studied). The RNA/DNA ratio was correlated with the G-index of muscle growth for juveniles (r 2=0.55). A much weaker correlation was observed for the maturing scallops (r 2=0.18), probably because of the interaction between reproductive and somatic growth. In fully mature scallops, somatic growth was negligible and the RNA/DNA ratios appeared to be inversely related to the level of physiological stress of the scallops. Whereas RNA/DNA ratios are difficult to interpret for maturing E. ziczac, because an increased ratio can be due to either increased gonadal or somatic growth, they are useful in predicting growth in juveniles and physiological stress in fully mature scallops.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00347449
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Seasonal variation in the properties of muscle mitochondria from the tropical scallop Euvola (Pecten) ziczac (1997)
    Springer
    Marine biology 128 (1997), S. 247-255 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In scallops, gametogenesis leads to considerable transfer of energetic reserves from the adductor muscle to the gonads. During an annual cycle, the scallops are exposed to changes in temperature and food availability. As these changes may affect muscle metabolic capacities, we examined whether the properties of the mitochondria in the phasic adductor muscle were modified during the annual cycle of the scallop Euvola (Pecten) ziczac (L. 1758). During our study, temperature and chlorophyll a levels generally showed an inverse relationship: high temperatures and low chlorophyll a levels occurred from mid-April to early June. Lower temperatures and higher chlorophyll a levels were found from January to late March and from mid-June to mid-September. Throughout the annual cycle, the substrate preferences and the pH sensitivity of the isolated muscle mitochondria changed little, whereas the maximal oxidative capacities and respiratory control ratios (RCR) varied considerably. Consistently, the maximal capacities for substrate oxidation were 30 to 80% lower in mitochondria isolated in May than at other times in the year. The RCR values of mitochondrial oxidation of glutamate, glutamine and succinate varied throughout the year with lower values characterizing the mitochondria from scallops harvested in May and in certain cases in August. In May, adductor muscles had lower protein levels than at other times. These data suggest that the requirements of gametogenesis, coupled with␣the high temperatures and low food availability occurring during April and May, led to a mobilization of muscle proteins which concomitantly decreased the oxidative capacity of isolated mitochondria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050089
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    Paper (German National Licenses)
    Fulltext
  • 3
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    Growth and survival of the winged oyster Pteria colymbus in suspended culture: influence of environmental factors associated to upwelling periods (2017)
    Springer
    In:  Aquaculture International, 25 (4). pp. 1653-1666.
    Details
    Publication Date: 2020-02-06
    Description: The present study examines the influence that environmental variables exerted on changes in condition index (CI), shell height (SH—dorsal-ventral axis) and soft tissue mass increments (STM) of the winged oyster Pteria colymbus in suspended culture during periods of upwelling (December to April) and non-upwelling (August to November) in the Cariaco Gulf, northeastern Venezuela. Environmental variables recorded between April 2012 and May 2013 included seston, water transparency, temperature, dissolved oxygen, chlorophyll a (Chl a) and the upwelling index (UI). Individuals were cultivated in lantern nets with an overall density of 56 individuals/0.123 m2. From three randomly chosen baskets, five individuals were sampled each month and changes in CI, STM and SH were related to the environmental variables using Spearman correlation and PCA. Results show that during upwelling, both Chl a and UI presented a positive and significant relationship with the oyster condition and growth parameters. During non-upwelling (low UI), this relationship was inverse, demonstrating the important influence of upwelling and non-upwelling periods on the ecophysiology of the species. Furthermore, it was shown that the non-upwelling, characterized by high temperatures and low food availability, is a critical period for P. colymbus, judging by a decrease in growth and survival rate. Nonetheless, this species reached 50 mm in 5 months, a size considered as commercially viable, suggesting that the study area is favourable to the cultivation of the winged oyster despite a dramatic decrease in upwelling intensity in the last decade.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1007/s10499-017-0141-2
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
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    Unknown
    Producción de biomasa de la microalga marina Chroomonas sp., en función del pH, intensidad luminosa y salinidad (2009)
    INVEMAR - Santa Marta, Colombia
    Details
    Publication Date: 2021-05-19
    Description: Se reporta la caracterización de la microalga marina Chroomonas, aislada de una laguna salina ubicada al Norte de Maracaibo, Estado Zulia, Venezuela. El crecimiento y producción de pigmentos en cultivos discontinuos, se evaluó en función de la salinidad (5, 10, 35, 50, 70 y 100 ppm), intensidad luminosa (39, 78, 117 y 156 µmol quanta.m-2.s-1) y pH (5.0, 5.5, 6.0, 7.0, 8.0 y 9.0). La mayor densidad celular de 117.99±2.62x106 cel.ml-1, se alcanzó a 35 ppm, 156 µmol quanta.m-2.s-1 de intensidad luminosa y a un pH entre 6.0 y 8.0. El contenido celular de clorofila total y carotenoides se incrementa con la salinidad hasta 100 ppm, con 246.55±61.8 y 69.79±18.19 fg.cel-1 respectivamente. Chroomonas sp. demostró alta capacidad de producción de biomasa y de pigmentos cuando se cultivó a un volumen de 2.0 l en régimen semicontinuo y a una tasa de renovación diaria del 30 %. La productividad celular fue de 4.31x109 cel.l-1d-1; mientras que la de clorofila total y carotenoides de 1.4 mg.l-1.d-1 y 0.48 mg.l-1.d-1, respectivamente. Estos resultados indican que esta microalga planctónica podría ser utilizada diariamente como alimento vivo en acuicultura y para la producción de biomasa microalgal y/o pigmentos.
    Description: We report the characterization of a marine microalga of the genus Chroomonas, isolated from a salt lagoon located to the north of Maracaibo, Zulia State, Venezuela. We evaluated the growth and the pigment production in discontinuous culture at different salinites (5, 10, 35, 50, 70 Y 100 ppm),Iight intensites (39,78,117 and 156 µmol quanta.m-2.s-1) and pH (5.0,5.5,6.0,7.0, 8.0 and 9.0). The highest cellular density, 117.99±2.62x106 cel.ml-1, was reached at 35ppm, 156 µmol quanta.m-2.s-1 of light intensity and a pH between 6.0 and 8.0. The cellular content of total chlorophyll and carotenoids increased with the salinity up to 100 ppm, with amounts of 246.55±61.8 and 69.79±18.19 fg.cel-1 respectively. The cellular productivity 4.31x109 cel.l-1d-1 was obteined when the microalga, was grown in semi-continuous culture, at a 2.0 I volume and at a daily renewal rate of 30 % (v/v). The total amount of chlorophyll and carotenoids 1.4 mg.l-1.d-1 and 0.48 mg.l-1.d-1 respectively. This results indicate that this planktonic microalga could be used as daily live food for larvae in aquaculture and for the production of microalgaI biomass and/or pigments.
    Description: Published
    Description: Parapontocaris; Parapontophilus; Prionocrangon
    Keywords: Continental slope
    Repository Name: AquaDocs
    Type: Journal Contribution
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    PAPER (OA)
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