Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    The effect of food availability, age or size on the RNA/DNA ratio of individually measured herring larvae: laboratory calibration (1994)
    Springer
    Marine biology 118 (1994), S. 377-382 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract RNA/DNA ratios in individual herring (Clupea harengus) larvae (collected from Kiel Bay, Baltic Sea, in 1989) were measured and proved suitable for determining nutritional status. Significant differences between fed and starving larvae appeared after 3 to 4 d of food deprivation in larvae older than 10 d after hatching. The RNA/DNA ratio showed an increase with age or length of the larvae and was less pronounced in starving larvae compared to fed larvae. The individual variability of RNA/DNA ratios in relation to larval length of fed larvae and of larvae deprived of food for intervals of 6 to 9 d is presented. Based on the length dependency and the individual variability found within the RNA/DNA ratios, a laboratory calibration is given to determine whether a larva caught in the field has been starving or not. An example for a field application is shown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350294
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Various methods to determine the gonadal development and spawning season of the purplish Washington clam, Saxidomus purpuratus (Sowerby) (2005)
    Berlin, Germany : Blackwell Verlag GmbH
    Journal of applied ichthyology 21 (2005), S. 0 
    Details
    ISSN: 1439-0426
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The monthly variation in reproductive cycle, condition factor (fatness), gonad index (GI), ovarian egg diameter and biochemical composition [RNA, DNA content and their ratio RNA/DNA (R/D)] were compared to determine the spawning season of the purplish Washington clam, Saxidomus purpuratus, collected from the west sea of Taean, Korea. All these factors were correlated to the spawning season from May to October. Monthly variation and concentration of the R/D ratio especially represented indicative information about the processes of gonad development and spawning patterns. The increases in R/D ratio in the ovaries corresponded with increases in ovarian egg diameters and the GI during the spawning season. The peak of R/D and RNA content in females was a good indicator of sexual maturation and the DNA content in males. During winter between November and January, the value of fatness, GI, egg size, RNA and DNA content were lower than in other seasons, indicating depletion of energy reserves and lower metabolic demands because of colder temperatures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1439-0426.2004.00636.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    RNA/DNA ratios of laboratory-reared and wild herring larvae determined with a highly sensitive fluorescence method (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 35 (1989), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1989.tb03078.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Nutritional condition and vertical distribution of Baltic cod larvae (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 51 (1997), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Newly hatched Baltic cod Gadus morhua larvae are typically found at depths 〉60 m. This is a region of low light and prey availability, hence generating the hypothesis that larvae have to migrate from hatching depth to the surface layer to avoid starvation and improve their nutritional condition. To test this hypothesis, Baltic cod larvae were sampled during the spawning seasons of 1994 and 1995 with depth-resolving multiple opening/closing nets. Each larva was aged by otolith readings and its RNA/DNA ratio was determined as a measure of nutritional condition. The RNA/DNA ratios of these larvae aged 2-25 days (median 10 days) ranged from 0.4 to 6.2, corresponding to levels exhibited by starving and fast-growing larvae in laboratory calibration studies (starvation, protein growth rate, Gpi= -12.2% day−1; fastgrowing larvae, Gpi=14.1%day−1) respectively. Seventy per cent of the field caught larvae had RNA/DNA ratios between the mean values found for starving and fed laboratory larvae. Only larvae aged 8-11 days had higher mean RNA/DNA ratios above 45 m than below (t-test, P〈0.05). However, the instantaneous protein growth rates were significantly higher for all larval age groups in the surface layers (t-test, P〈0.05). Starving larvae were found in all depths sampled (10-85 m), whereas growing larvae (positive Gpi) were restricted to samples taken shallower than 45 m. These superior growth rates above 45 m corroborate the hypothesis and imply that migration to the shallow water layers is a prerequisite for good nutritional condition, growth and survival of Baltic cod larvae. The frequent occurrence of cod larvae older than 8 days in the deep water in poor condition suggests that a proportion of the larvae will die from Starvation in the deep layers of the Baltic Sea.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1997.tb06108.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Ontogenic changes in the allometric scaling of the mass and length relationship in Sprattus sprattus (2005)
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    Journal of fish biology 66 (2005), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: An analysis of mass (M) and standard length (LS) data for larval, juvenile and adult sprat (Sprattus sprattus; Clupeidae) revealed marked changes in the allometric scaling factor (b in 〈inlineGraphic alt="inline image" href="urn:x-wiley:00221112:JFB651:JFB_651_mu1" location="equation/JFB_651_mu1.gif"/〉). For sprat 〈44 mm LS, b was 5·0, whereas in larger juveniles and adults, b was c. 3·4 indicating a relatively protracted metamorphic period for this species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.0022-1112.2005.00651.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Variability in condition and growth of Atlantic cod larvae and juveniles reared in mesocosms: environmental and maternal effects (2003)
    Oxford, UK : Blackwell Science Ltd
    Journal of fish biology 62 (2003), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Standard length, dry mass and RNA : DNA ratio measurements of 3876 Atlantic cod Gadus morhua larvae and juveniles from 26 families of recruit (fish during their first year of spawning) and repeat spawners (fish which were in their subsequent spawning season) reared in two mesocosms (2500 and 4400 m3) under semi-natural conditions were analysed over a period of 10 weeks using microsatellites. Larvae from recruit spawners were significantly longer and heavier at hatch and throughout the 10 weeks. RNA : DNA ratios from recruit spawner offspring were only significantly higher at week 1. The smaller (2500 m3) mesocosm was characterized by low plankton density during the transition from endogenous to exogenous feeding followed by a higher density during the metamorphosis period (weeks 4 and 5), with the reverse pattern evident in the 4400 m3 mesocosm. Patterns of larval growth followed patterns of zooplankton density. Significant differences in RNA : DNA ratios between the mesocosms at all comparable sampling dates were found and within each mesocosm individual fish exhibited a wide range of growth and condition responses under the same environmental conditions. RNA : DNA ratios as a function of size differed in the amount of variability between mesocosms, indicating that the higher food density led to a higher proportion of well-conditioned larvae in the first 3 weeks. Food availability probably has a major role in determining offspring growth and condition, with limited effects due to maternal effects in cases where the broodstock females are approximately of similar size and condition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1095-8649.2003.00060.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...