scholarly journals Contributions to the knowledge of the Biology of the Arabian Abalone Haliotis mariae Wood, 1828

1996 ◽  
Vol 1 ◽  
pp. 33
Author(s):  
J. Stirn ◽  
K. A. AI-Hashmi
Keyword(s):  
Growth Rate ◽  
Fisheries Management ◽  
Larval Settlement ◽  
Larval Rearing ◽  
Artificial Reproduction ◽  
Laboratory Rearing ◽  
Abalone Species ◽  
Pelagic Eggs ◽  
Ecological Importance ◽  
One Year

The Arabian abalone occur in the Arabian Sea’s rocky coastal zone in association with conspicuous macrolgal communities in which it represents the dominant herbivorous component. Despite such ecological importance and although the commercial exploitation of abalone presents a considerable contribution to Omani fisheries, almost nothing is known about the biology of this species. This report presents results of research carried out in the field and with laboratory cultures, and draws general conclusions related also to the fisheries management of these possibly overexploited abalone populations, Cobort observations in the field and measured increments of cultured specimens showed a growth rate significantly higher than in other abalone species, i.e. greater than 3 mm shell-increment per month. The very early sexual maturity demonstrated by captivity spawnings of approximately one year old animals is also quite unusual. The ejected eggs formed mucous mono layers attached to the substratum whereas other abalone species produce pelagic eggs. Jvenile coborts in nature and the periodic spawning of cultured animals indicate the major spawning in spring and postmonsoon one in autumn. The models previously applied in fisheries management of abalone in Oman assumed only one spawning per year, the first being at age 2+, and a slower growth-rate. These models should be reconsidered using the new data, which may partially explain why abalone are less overexploited than one would expect looking at heavy harvesting. In view of a projected commercial abalone cultivation our laboratory rearing experiments showed that both natural and/or artificial food may be used, provided this contains-apart from standard ingredients, the seaweed-borne components (probably phycobillins) required for a normal parasite , resistant shell formation. With regard to artificial reproduction,  our preliminary trials showed that spawning , fertilization ,and initial larval rearing present no problems. The steps from the pediveliger to larval settlement, however ,seem to be fatally exposed to eilitate attacks. Further research is needed in order to eliminate this critical problem.

scholarly journals Growth of the ass's ear abalone (Haliotis asinina Linné) on Heron Reef, tropical eastern Australia

1995 ◽  
Vol 46 (3) ◽  
pp. 571 ◽  
Author(s):  
DC McNamara ◽  
CR Johnson
Keyword(s):  
Growth Rate ◽  
Shell Length ◽  
Frequency Distributions ◽  
Haliotis Asinina ◽  
Length Relationship ◽  
Abalone Species ◽  
Eastern Australia ◽  
Field Peak ◽  
One Year

Growth of ass's ear abalone (Haliotis asinina) was measured in situ (mark-recapture of adults) and in aquaria (juveniles) on Heron Reef, Queensland. A growth curve (y = 4.27L2.03 e-u, where y is the growth rate, L is the shell length, and u = 0.27L0.88) fitted to these data indicated a sigmoidal age-length relationship. It is estimated that H. asinina may grow from 2 mm to 35.6 mm in shell length in six months and 55.0 mm in one year. These growth estimates are consistent with temporal shifts in the size-frequency distributions of juveniles in the field. Peak growth rates, estimated at over 120 mm year-1 in young abalone (approximately 3-4 months of age), are the highest recorded for any abalone species.

scholarly journals ECOLOGICAL STUDIES ON NEPENTHES AT BARITO ULU, CENTRAL KALIMANTAN, INDONESIA

2011 ◽  
Vol 9 (3) ◽  
Author(s):  
Muhammad Mansur
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Stem Length ◽  
Ecological Studies ◽  
Central Kalimantan ◽  
Length Growth ◽  
Small Plot ◽  
Heath Forest ◽  
One Year ◽  
The One

Ecological studies on the Nepenthes species at Barito Ulu, Central Kalimantan, Indonesia were conducted between August 2005 and September 2006. Surveys and two small plot inventories were used to determine the diversity and population of Nepenthes at the study site. We found eight Nepenthes species around the BaritoUlu study area: N. albomarginata, N. ampullaria, N. gracilis, N. hirsuta, N. rafflesiana, N. reinwardtiana, N. stenophylla, and N. hispida. Plot A was dominated by N. rafflesiana with one other species found; whilst in plot B we found five species but it was also dominated by N. rafflesiana. In plot A, the one year stem length growth rate of N. albomarginata was faster than N. rafflesiana (5.0 and 3.5 cm respectively). While in plot B, N. gracilis (21.7 cm) and N. reinwardtiana (13.1 cm) showed faster growth rates than N. albomarginata (5.2 cm), N. rafflesiana (7.0 cm) and N. stenophylla (8.5 cm). Generally, the habitat of Nepenthes in the study site is heath forest.

scholarly journals Ewe reproductive performance and growth rate of suckling-lambs on endophyte-infected perennial ryegrass pasture

1999 ◽  
Vol 7 ◽  
pp. 19-26
Author(s):  
R.H. Watson ◽  
R.G. Keogh ◽  
M.F. Mcdonald
Keyword(s):  
Growth Rate ◽  
Perennial Ryegrass ◽  
Reproductive Performance ◽  
Growth Rates ◽  
Ovulation Rate ◽  
Grazing Management ◽  
One Year ◽  
Lamb Growth

Two groups (n=39) of Romney breeding ewes were maintained under the same grazing management on either endophyte-infected (E+) or endophytefree (E-) perennial ryegrass pasture for two years (1997-1998) following a one-year equilibration period. The ewes were naturally mated in March each year and ovulation rate at 1st mating was measured, and conception and the number of lambs born and weaned were recorded. All ewes were weighed monthly and lamb growth rates were determined between birth and weaning. Mean mating date was delayed by 1.8 days (P

Selection for components of efficient lean growth in Landrace pigs

1994 ◽  
Vol 1994 ◽  
pp. 10-10
Author(s):  
M.K. Curran ◽  
N.D. Cameron
Keyword(s):  
Growth Rate ◽  
Selection Criteria ◽  
Conversion Ratio ◽  
Control Line ◽  
Food Conversion ◽  
Lean Growth ◽  
Food Conversion Ratio ◽  
Daily Food ◽  
Selection For ◽  
One Year

To study responses to divergent selection for lean growth rate (LGA), lean food conversion ratio (LFC) and daily food intake (DFI), an experiment was started in 1984 at Edinburgh and Wye. This paper measured the selection pressure applied, the responses in the selection criteria and estimated the genetic and phenotypic relationships between the selection criteria with ad-libitum feeding of Landrace pigs after four generations of selection.The LGA (LFC) selection objective was to obtain equal correlated responses in growth rate (food conversion ratio) and carcass lean content, measured in phenotypic s.d. The LGA, LFC and DFI selection criteria had phenotypic s.d. of 32, 29 and 270 units and results are presented in s.d. units.Boars and gilts were purchased from eight British nucleus herds and boars from national artificial insemination centres in 1982. Homozygous or heterozygous halothane positive pigs were not included in the experiment. The base population consisted of 20 sires and 89 dams. Within each of the three selection groups, there were high and low selection lines with a control line, each consisting of 10 boars and 20 gilts, with a generation interval of one year. There were two control lines, one for LGA and one for LFC and DFI, as selection groups were arrowed continuously. The total number of pigs tested per line and average inbreeding coefficient at generation 4, within selection group are given below.

Body growth and its implications in population dynamics of Acanthodactylus erythrurus (Schinz, 1834) in the Eastern Iberian peninsula

2019 ◽  
Vol 40 (3) ◽  
pp. 305-312
Author(s):  
Robby Marcel Drechsler ◽  
Juan Salvador Monrós
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Statistical Significance ◽  
Growth Curves ◽  
High Statistical Significance ◽  
General Data ◽  
One Year ◽  
Best Fit ◽  
Logarithmic Growth

Abstract We calculated growth rate for the spiny-footed lizard (Acanthodactylus erythrurus) inhabiting coastal eastern Spain from long-term mark-recapture data. Growth curves differ between sexes, with males growing faster than females and achieving larger size maximums. In this population each sex reaches maturity at about 300 days of age, approximately 34% faster than males, and 28% faster than females studied in a population further south and west in Iberia. Our logarithmic growth model has an accuracy of 96.8% and high statistical significance ( for males and for females). Although both the exponential curve of “best fit” for growth estimated for males (), and the linear curve of “best fit” estimated for females () in a population from Cádiz (Busack and Jaksic, 1982) are also significant. The overlap between growth curves and the general data cloud of the population showed that at the end of the year the proportion of individuals younger than one year was 80% and the proportion of individuals older than one year was 20%. Our data, in agreement with calculated maximum life spans for males (1.9 years) and females (2.1 years) in Cádiz, suggest a life span of approximately two years for both sexes. Females seem to reproduce only in a unique season in their lives, at this locality, as in Cádiz (Busack and Klosterman, 1987) they likely lay only one clutch, whereas females in Morocco (Bons, 1962) may produce two.

ENZYME HETEROZYGOSITY ASSOCIATED WITH GROWTH AT DIFFERENT DEVELOPMENTAL STAGES IN OYSTERS

1982 ◽  
Vol 24 (4) ◽  
pp. 451-458 ◽  
Author(s):  
Shiva M. Singh
Keyword(s):  
Growth Rate ◽  
Prince Edward Island ◽  
Developmental Stages ◽  
Age Groups ◽  
Age Group ◽  
Cape Breton ◽  
Random Samples ◽  
Specific Mortality ◽  
One Year ◽  
Polymorphic Enzymes

Following our earlier reports on one-year-old oyster populations of Prince Edward Island (Singh and Zouros, 1978, 1981; Zouros et al., 1980), cohorts of three-year classes were studied from Cape Breton, Nova Scotia. Random samples of about 200 individuals from each year class were analyzed for four polymorphic enzymes. A number of generalizations emerged. There was a general deficiency of heterozygotes in the three age groups and this deficiency decreased with age (reflecting reduction in heterozygote deficiency). This suggests genotype-specific mortality during ontogeny. The deficiency of heterozygotes was more pronounced in slower growing, lighter individuals than in faster growing, heavier individuals. The number of heterozygous loci per individual was positively correlated with mean growth rate. The variance in weight was lower in heterozygotes; it decreased with increase in number of heterozygous loci in a given age group. Overdominance in growth rate appears to be the most plausible explanation for these observations.

scholarly journals Utilization Efficiency of Yolk Egg on Maanvis (Pterophyllum scalare) Embryos and Larvae in Different Incubation Temperatures

2007 ◽  
Vol 4 (1) ◽  
pp. 57 ◽  
Author(s):  
T. Budiardi ◽  
W. Cahyaningrum ◽  
I. Effendi
Keyword(s):  
Growth Rate ◽  
Incubation Time ◽  
Egg Yolk ◽  
Utilization Efficiency ◽  
Hatching Rate ◽  
Larval Rearing ◽  
Optimum Temperature ◽  
Egg Hatching ◽  
Incubation Temperatures ◽  
Pterophyllum Scalare

<p>This study was performed to determine the efficiency of yolk egg utilization in embryos and larvae, hatching rate, incubation time to hatch, and growth rate of maanvis (<em>Pterophyllum scalare</em>) larvae incubated at room remperature, 27<sup>o</sup>C, and 30<sup>o</sup>C.  Results of study showed that yolk egg utilization efficiency of embryos and larvae incubated at 30<sup>o</sup>C was 73.70% and 0,18%, respectively, and no different with that of room and 27<sup>o</sup>C incubation temperatures.  Hatching rate of eggs incubated at 30<sup>o</sup>C (84.75%) was also same with that of other treatments.  However, incubation time to hatch (27.41 hours) was shorter than that of other treatments.  The growth rate by length of larvae (2.16%) and survival rate (75.28%) incubated at 30<sup>o</sup>C was also higher compared with that of other treatments.  Thus, in general, optimum temperature for egg hatching and larval rearing of maanvis was 30<sup>o</sup>C.</p> <p>Keywords: maanvis, <em>Pterophyllum scalare</em>, egg yolk, larvae, embryo, temperature</p> <p> </p> <p>ABSTRAK</p> <p>Penelitian ini dilakukan untuk mengetahui efisiensi pemanfaatan kuning telur pada embrio dan larva, derajat penetasan, lama inkubasi telur hingga menetas, dan laju pertumbuhan serta kelangsungan hidup larva ikan maanvis (<em>Pterophyllum scalare</em>) yang diinkubasi pada suhu ruang, 27<sup>o</sup>C dan 30<sup>o</sup>C.  Hasil penelitian menunjukkan bahwa nilai efisiensi pemanfaatan kuning telur bila diinkubasi pada suhu 30<sup>o</sup>Csebesar 73,70% pada fase embrio dan 0,18% pada fase larva, dan tidak berbeda dengan suhu ruang dan 27<sup>o</sup>C.  Demikian juga dengan derajat penetasan telur  (84,75%) tidak berbeda dengan perlakuan lainnya.  Sementara itu, lama inkubasi telur hingga menetas (27,41 jam) lebih cepat dibandingkan dengan suhu inkubasi perlakuan lainnya. Demikian juga dengan laju pertumbuhan panjang (2,16%) dan kelangsungan hidup larva (75,28%) lebih tinggi dibandingkan dengan perlakuan lainnya. Dengan demikian, secara umum suhu optimal untuk penetasan dan pemeliharaan larva ikan maanvis adalah 30°C.</p> <p>Kata kunci: ikan maanvis, <em>Pterophyllum scalare</em>, kuning telur, larva, embrio, suhu</p>

scholarly journals Volatility behavior of virtual currencies

2019 ◽  
Vol 10 (2) ◽  
pp. 537
Author(s):  
Jéssica Gonçalves Andrade ◽  
Nilson Brandalise
Keyword(s):  
Growth Rate ◽  
Data Analysis ◽  
Average Rate ◽  
Rate Of Return ◽  
Average Risk ◽  
Average Growth Rate ◽  
Average Growth ◽  
Volatility Analysis ◽  
One Year ◽  
Made In

In order to do a volatility analysis, since the exchange rate is higher than the average risk, the higher the average rate of return, the higher the average growth rate of the year. applied the method of data analysis. An attempt to volatility analysis can be made in one year, in the middle of the end of 2016.

scholarly journals Honey Market Dynamics. The Case of Romania

2018 ◽  
Vol 10 (2) ◽  
pp. 13-16
Author(s):  
Nancy Diana Panța
Keyword(s):  
Growth Rate ◽  
United Nations ◽  
European Commission ◽  
Empirical Data ◽  
Market Dynamics ◽  
Honey Production ◽  
Food And Agriculture ◽  
Producer Prices ◽  
One Year ◽  
The Eu

Abstract The aim of the present paper is to analyse the evolution of the Romanian honey market in the 2006-2016 period. The analysis, ran over a period of ten years, follows to depict honey’s market dynamics starting from 2006, one year before Romania’s accession to the EU. The used data consisted in empirical data provided by Food and Agriculture Organisation of the United Nations database, European Commission and National Institute of Statistics. Results indicated that Romania covers its honey consumption through production and that the country is a net honey exporter, recording a 30% growth rate in exports from 2006 to 2013. In the 2006-2016 period, Romania has managed to increase its beehives number by 58.81% and its honey production by 16.52%. Honey producer prices also went up by 42.99% in the analysed period.

scholarly journals Coral larvae for restoration and research: a large-scale method for rearing Acropora millepora larvae, inducing settlement, and establishing symbiosis

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3732 ◽  
Author(s):  
F. Joseph Pollock ◽  
Sefano M. Katz ◽  
Jeroen A.J.M. van de Water ◽  
Sarah W. Davies ◽  
Margaux Hein ◽  
...  
Keyword(s):  
Large Scale ◽  
Larval Settlement ◽  
Larval Survival ◽  
Coralline Algae ◽  
Larval Rearing ◽  
Crustose Coralline Algae ◽  
Minimal Impact ◽  
Acropora Millepora ◽  
Wide Range ◽  
Order Of Magnitude

Here we describe an efficient and effective technique for rearing sexually-derived coral propagules from spawning through larval settlement and symbiont uptake with minimal impact on natural coral populations. We sought to maximize larval survival while minimizing expense and daily husbandry maintenance by experimentally determining optimized conditions and protocols for gamete fertilization, larval cultivation, induction of larval settlement by crustose coralline algae, and inoculation of newly settled juveniles with their dinoflagellate symbiont Symbiodinium. Larval rearing densities at or below 0.2 larvae mL−1 were found to maximize larval survival and settlement success in culture tanks while minimizing maintenance effort. Induction of larval settlement via the addition of a ground mixture of diverse crustose coralline algae (CCA) is recommended, given the challenging nature of in situ CCA identification and our finding that non settlement-inducing CCA assemblages do not inhibit larval settlement if suitable assemblages are present. Although order of magnitude differences in infectivity were found between common Great Barrier Reef Symbiodinium clades C and D, no significant differences in Symbiodinium uptake were observed between laboratory-cultured and wild-harvested symbionts in each case. The technique presented here for Acropora millepora can be adapted for research and restoration efforts in a wide range of broadcast spawning coral species.

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