ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
Filter
Collection
Publisher
Years
  • 1
    Electronic Resource
    Electronic Resource
    Effect of initial age variation on production of Florida red tilapia fry under intensive, brackishwater tank culture (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Aquaculture research 24 (1993), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Growth and survival were compared among uniform- and mixed-age groups of Florida red tilapia fry during sex reversal in brackishwater (12ppt) tanks, under commercial-scale hatchery conditions. Three treatment groups of post-yolksac (i.e. free-swimming) stage fry of different age compositions were compared: (1) 100% fry collected at the free-swimming stage (FSF); (2) 100% fry obtained through artificial incubation of eggs and non-swimming sacfry (ENS); and (3) a mixed group consisting of 50% of each type (FSF+ENS). Fry were stocked into 530–1 cylindroconical tanks at a density of seven fish/l (3700/tank) and reared on an androgen-treated diet for 30 days. While specific growth rates (range = 17·1–17·8% body weight/day) did not differ (P 〉 0·05) among treatments, significant (P 〈 0.05) differences were observed for survival and feed conversion ratio (FCR). ENS showed highest survival (76·8%) and lowest FCR (1·14), FSF showed intermediate survival (59·2%) and FCR(l·33), while the mixed-age group (FSF+ENS) showed lowest survival (38·5%) and highest FCR (1·70). Under all treatments, a majority of fry losses were attributed to cannibalism. A highly significant (P 〈 0·001) negative regression between survival and coefficient of variation of initial weights (CV = SD/X̄) indicated that cannibalism was reduced by minimizing age/size variation at stocking. The CV of initial weight may be a useful parameter for predicting fry survival under intensive tank culture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2109.1993.tb00621.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Hatchery production of Florida red tilapia seed in brackishwater tanks: the influence of broodstock age (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Aquaculture research 22 (1991), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Production of Florida red tilapia seed (eggs, sacfry and fry) in 34-m2 above-ground tanks using recirculated brackishwater (12 ppt) was studied over a 5-month period on Lee Stocking Island (Exuma Cays, Bahamas). Four tanks were stocked with year class 1 (YCI) breeders, while 2 tanks were stocked with year class 2 (YCII) breeders at densities of 200 and 240/tank (5·9 and 7·1/m2), respectively, and at a sex ratio of 3 females to 1 male, beginning in November 1988. Seed production was measured by removing free-swimming fry from tanks and eggs and sacfry from the mouths of brooding females, and assessing the number of each at 15 to 16-day intervals from February to June 1989. Average seed production (seed/m2/day) was significantly higher in YCI (52·3) than in YCII (36·0) broodstock, indicating the advantages of replacing broodstock with yearling breeders each year.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2109.1991.tb00504.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Water and ion balance in hydrating oocytes of the grey mullet, Mugil cephalus (L.), during hormone-induced final maturation (1986)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 28 (1986), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Sequential changes in water content and inorganic ion concentrations occurring in intra-ovarian oocytes of the grey mullet, Mugil cephalus L., during hormone-induced final maturation are described. Post-vitellogenic oocytes have a water content of 59.4%. During final maturation, oocyte water increases rapidly to a maximum of 84.8% at oviposition. Hydration is accompanied by a relatively small increase in dry matter due to the concurrent uptake of inorganic ions and an apparent uptake of organic matter.Net uptake of Ca2+ during hydration is negligible. Net uptake of Mg2 + and Na+ occurs in less than equimolar proportions. Net uptake of K+ and Cl− occurs in greater than equimolar proportions prior to ovulation, returning to equimolarity at oviposition. Hence, hydration results in a dilution of intracellular Ca2+, Mg2+ and Na+ to minimum concentrations at oviposition. In contrast, K+ and Cl− concentrations are slightly elevated prior to ovulation, returning to initial levels at oviposition. A 1:1 stoichiometric relationship in net uptake of K + andCl− is evident.Intracellular osmotic pressure in post-vitellogenic oocytes is 203.4 ± 18.0 mOsmolkg−1. Osmotic pressure rises to a peak of 421.3+ 17.3 mOsmol kg−1 prior to ovulation, then declines to 313.3 ± 15.0 mOsmol kg−1 at oviposition. This rise in osmotic pressure prior to ovulation cannot be accounted for solely on the basis of inorganic ion uptake and must be attributed to changes in intracellular concentrations of organic solutes as well. An apparent increase in non-ash dry matter during hydration suggests that a net uptake of organic solute is involved. A relatively small organic molecule with high osmotic activity (e.g., amino acids) is implicated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1986.tb05180.x
    Location Call Number Expected 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...