Environmental factors affecting growth and survival of juvenile western rock lobsters Panulirus longipes (Milne-Edwards)

1975 ◽  
Vol 26 (2) ◽  
pp. 177 ◽  
Author(s):  
RG Chittleborough
Keyword(s):  
Growth Rate ◽  
Food Supply ◽  
Growth Increment ◽  
Dominant Factor ◽  
Feeding Rates ◽  
Continuous Darkness ◽  
Growth And Survival ◽  
Factors Affecting ◽  
In The Wild ◽  
The Impact

The effects of temperature, photoperiod, oxygen, food supply, crowding, and autotomy of limbs have been measured under controlled conditions in aquaria. Growth rate increased with temperature to a maximum 26� C above which both growth rate and survival declined. Varying the length of photoperiod did not affect growth rate or survival, except that the growth rate was depressed significantly in continuous darkness. A mild deficiency of oxygen (60-67 % saturation) resulted in a smaller size increment at a moult; depression to 47-55 % saturation caused deaths at ecdysis. Daily feeding was necessary to maintain maximum rate of growth. The fist response to decreased food supply was a reduction in frequency of moulting. More severe shortage of food also depressed growth increment per moult. Feeding rates and conversion ratios have been measured. Frequency of moulting (and hence growth rate) was depressed markedly when juveniles were held in isolation. At a moult replacing two lost limbs, the growth rate was not affected; replacement of four limbs reduced that moult increment. Single loss of up to four limbs did not result in an earlier moult, but repetitive loss of two or more limbs at or immediately after each ecdysis led to precocious moulting. The impact of these and other components of the environment (shelter, salinity, turbidity, competitors and predators) upon juveniles during the 4 years spent on shallow coastal reefs is discussed. Food supply is emerging as the dominant factor determining growth and survival in the wild population.

scholarly journals WATER QUALITY AND ITS EFFECT ON GROWTH AND SURVIVAL RATE OF LOBSTER REARED IN FLOATING NET CAGE IN EKAS BAY, WEST NUSA TENGGARA PROVINCE

2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Muhammad Junaidi ◽  
Mat Sardi Hamzah
Keyword(s):  
Water Quality ◽  
Growth Rate ◽  
Survival Rate ◽  
Quality Data ◽  
Dominant Factor ◽  
Growth And Survival ◽  
Water Quality Status ◽  
Net Cage ◽  
Quality Status ◽  
Effect On Growth

ABSTRACT The development of lobster farming in floating net cage in Ekas Bay caused an environmental degradation such as decrease water quality due to some aquaculture wastes. The purposes of this study were to determine the status of water quality and their effect on growth and survival rate of lobster reared in floating net cages (FNC) in the Ekas Bay, West Nusa Tenggara Province. Water sample collection and handling referred to the APHA (1992). Analyses of water quality data were conducted using Principal Component Analysis. Determination of the water quality status of Ekas Bay was performed with STORET system. Multivariate analyses were used to determine the relationship between water quality, growth, and survival rate of lobster reared in FNC. Results showed that Ekas Bay water quality status was categorized in class C (medium contaminated), which exceeded some quality standard parameters such as ammonia (0.3 mg/l), nitrate (0.008 mg/l), and phosphate (0.015 mg/l). During lobster farming activities feeding with trash fish for 270 days, we obtained daily growth rate of  0.74% (lower than normal growth rate of 0.86%), survival rate of 66% (lower than normal survival rate of 86.7%), and feed conversion ratio of 11.15. Ammonia was found as a dominant factor reducing growth  and survival rate of lobster reared in FNC. Keywords: water quality, lobsters, growth, survival, Ekas Bay

scholarly journals Environmental and Management Factors Affecting Carrot Cracking

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 852B-852
Author(s):  
T.K. Hartz* ◽  
P.R. Johnstone ◽  
J.J. Nunez
Keyword(s):  
Air Temperature ◽  
Impact Test ◽  
Irrigation Management ◽  
Nutrient Status ◽  
N Fertilization ◽  
Impact Testing ◽  
Dominant Factor ◽  
Factors Affecting ◽  
The Impact ◽  
Cracking Sensitivity

Cracking of carrot (Daucus carota L.) roots during harvest and handling is a serious problem for the commercial industry, particularly for `cut and peeled' products. Thirty commercial fields of cv. `Sugar Snax' in California were surveyed over the period 2000-03. Soil texture was determined, and soil and crop nutrient status, air temperature and soil moisture were monitored. In 10 fields the effect of excessive N fertilization was investigated; 90-180 kg·ha-1 N was sidedressed in addition to the growers' N regime. At one site a comparison of 10 cultivars was conducted to determine the root cracking sensitivity of commercial cultivars suitable for the cut and peeled market. In all fields roots were hand harvested, with undamaged roots 18-24 mm in diameter selected for study. Roots were cooled to 5 °C and subjected to an impact test to rate cracking sensitivity. Fields varied widely in root cracking sensitivity, with 4% to76% of roots cracked in the impact test. Cracking sensitivity was positively correlated with the % silt and clay in soil, and with air temperature in the final month of growth. Irrigation management had no consistent effect on cracking sensitivity. N application in excess of the growers' N regime did not increase carrot yield, but increased root cracking sensitivity by an average of 30%. Root cracking varied among cultivars from 10% to 49%. However, when the periderm was peeled from roots before impact testing, incidence of cracking declined to 2% or less in all cultivars. Periderm strength or flexibility is apparently the dominant factor in carrot cracking sensitivity, and environmental and management variables that affect cracking sensitivity must do so by affecting the periderm structure.

scholarly journals Pertumbuhan dan Sintasan Juvenil Teripang Pasir Holothuria scabra pada Pemeliharaan Dengan dan Tanpa Rumput Laut Gracilaria sp., Menggunakan Keramba Apung dan Tancap di Tambak

2020 ◽  
Vol 5 (3) ◽  
pp. 199
Author(s):  
Dedy Kurnianto ◽  
Lisa Fajar Indriana ◽  
Abdul Wahab ◽  
Syafriyadi Hafid ◽  
Balkam Fadlan Badi
Keyword(s):  
Water Quality ◽  
Growth Rate ◽  
Quality Parameters ◽  
Raw Material ◽  
Growth And Survival ◽  
Randomized Design ◽  
Significant Difference ◽  
In The Wild ◽  
Completely Randomized Design ◽  
Increment Growth

<p><strong>Growth and Survival of Sandfish <span style="text-decoration: underline;">Holothuriascabra</span> Juveniles </strong><strong>Grown </strong><strong>with and without Seaweed <span style="text-decoration: underline;">Gracilaria</span> sp</strong><strong>.,</strong><strong> using Floating and Fixed Hapas in </strong><strong>Earthen </strong><strong>Pond</strong><strong>. </strong><span style="text-decoration: underline;">Holothuriascabra</span> known as sandfish have long been used for pharmaceutical, cosmetic, and food industries.Juveniles production is one of the ways to address the problem of raw material availability due to declining sandfish population in the wild. This research aimed to determine growth performance and survival of sandfish juveniles reared with and without seaweed <span style="text-decoration: underline;">Gracilaria</span> sp.  using floating and fixed hapas in earthen pond. The research was conducted from May to September 2014. A completely randomized design was used to arrange 12 hapas of four treatments groups with three replicates including floating hapas without <span style="text-decoration: underline;">G</span><span style="text-decoration: underline;">racilaria</span> sp. (ATR), floating hapas with <span style="text-decoration: underline;">G</span><span style="text-decoration: underline;">racilaria</span>sp. (ADR), fixed hapas without <span style="text-decoration: underline;">G</span><span style="text-decoration: underline;">racilaria</span> sp. (TTR) and fixed hapas with <span style="text-decoration: underline;">G</span><span style="text-decoration: underline;">racilaria</span> sp. (TDR). Some parameters was observed includingweight increment, Growth Rate (GR),Specific Growth Rate(SGR), Biomass, Survival, and Water Quality. The result showed that GR and SGR were not significantlydifferent among treatments (P&gt;0.05). Survial and Biomass showed significant difference among treatments (P &lt;0.05). ATR has the highest GR, SGR, survival, dan biomass whereas TDR has the lowest GR, SGR, survival, dan biomass. Water quality parameters were in optimal range for sandfish rearing. Added<span style="text-decoration: underline;">G</span><span style="text-decoration: underline;">racilaria</span> sp.tend to inhibitGR, SGR, survival, dan biomass.<strong></strong></p>

scholarly journals Factors Affecting the Profitability of Insurance Companies in Albania

2016 ◽  
Vol 1 (1) ◽  
pp. 352
Author(s):  
Dorina Kripa ◽  
Dorina Ajasllari
Keyword(s):  
Growth Rate ◽  
Quantitative Methods ◽  
Performance Metrics ◽  
Annual Reports ◽  
Insurance Companies ◽  
Company Size ◽  
Factors Affecting ◽  
Fixed Assets ◽  
The Impact ◽  
A Company

Good performance of a company determines the position of the company in its market and the growth and consolidation of the market, giving as result the development of the economy as a whole. The importance of this topic further enhanced when dealing with insurance companies because: 1) insurance companies’ transfers risk in the economy 2) provide a mechanism to promote savings 3) promote investment activities. The growing importance of insurance companies in Albania and the importance of profitability as one of the key performance metrics of a company are the reasons why we decide to write this paper. The variation of profits between insurance companies over the years, within a country, leads to believe that internal factors play a major role in determining profitability. We have taken under study the impact of growth rate, liabilities, liquidity, fixed assets, volume of capital and company size on the profitability of insurance companies. The methodology used is based on quantitative methods and the data are provided by reliable sources such as annual reports of insurance companies’, FSA reports and NRC . We have taken under study 7 companies, including non-life and life insurance companies, from 2008- 2013. The results of the paper show that factors such as growth rate, liabilities, liquidity and fixed assets are the main factors affecting the profitability of insurers, where the growth rate is positively associated with profitability, while liabilities, liquidity and fixed assets are negatively correlated. Company size and the volume of capital are positively correlated with the profitability of insurance companies’, but their impact is statistically insignificant.

Impact of Planting Depth on Fraxinus pennsylvanica ‘Patmore’ Growth, Stability, and Root System Morphology

2019 ◽  
Vol 45 (6) ◽  
Author(s):  
Jason Miesbauer ◽  
Andrew Koeser ◽  
Gary Kling ◽  
Gitta Hasing ◽  
Marvin Lo
Keyword(s):  
Tree Height ◽  
Past Research ◽  
Fraxinus Pennsylvanica ◽  
Green Ash ◽  
Planting Depth ◽  
Tree Stability ◽  
Growth And Survival ◽  
Factors Affecting ◽  
Pull Tests ◽  
The Impact

Trees are often deeply planted as a result of nursery and landscape practices. While past research has investigated the impact of deep planting on tree growth and survival, its impact on whole-tree stability is not well documented. Green ash (Fraxinus pennsylvanica ‘Patmore’) trees were planted at three different depths in research plots and established for nine years. In assessing aboveground growth, planting depth had no effect on stem diameter growth (measured as dbh) (P = 0.421; n = 32) or tree height (P = 0.501; n = 32). Static pull tests were conducted to evaluate the consequences of deep planting on tree stability. Using structure from motion (SfM) photogrammetry-derived computer models to assess root architecture, we found the most significant factors affecting tree stability were: 1) root volumes in the top 10 cm of the soil in a 90° wedge on the side opposite of the pull direction; 2) root volumes 40.1 to 50 cm deep in a 90° wedge on the side opposite of the pull direction; and 3) root volumes deeper than 60.1 cm deep in a 90° wedge on the side opposite of the pull direction (final model: P < 0.001; n = 30; adjusted R2 = 0.852). The importance of structural root morphology throughout the soil profile and implications for urban root-soil relations on tree stability are discussed.

scholarly journals WATER QUALITY AND ITS EFFECT ON GROWTH AND SURVIVAL RATE OF LOBSTER REARED IN FLOATING NET CAGE IN EKAS BAY, WEST NUSA TENGGARA PROVINCE

2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Muhammad Junaidi ◽  
Mat Sardi Hamzah
Keyword(s):  
Water Quality ◽  
Growth Rate ◽  
Survival Rate ◽  
Quality Data ◽  
Dominant Factor ◽  
Growth And Survival ◽  
Water Quality Status ◽  
Net Cage ◽  
Quality Status ◽  
Effect On Growth

<p><strong><em>ABSTRACT</em></strong></p> <p><em>The development of lobster farming in floating net cage in Ekas Bay caused an environmental degradation such as decrease water quality due to some aquaculture wastes. The purposes of this study were to determine the status of water quality and their effect on growth and survival rate of lobster reared in floating net cages (FNC) in the Ekas Bay, West Nusa Tenggara Province. Water sample collection and handling referred to the APHA (1992). Analyses of water quality data were conducted using Principal Component Analysis. Determination of the water quality status of Ekas Bay was performed with STORET system. Multivariate analyses were used to determine the relationship between water quality, growth, and survival rate of lobster reared in FNC. Results showed that Ekas Bay water quality status was categorized in class C (medium contaminated), which exceeded some quality standard parameters such as ammonia (0.3 mg/l), nitrate (0.008 mg/l), and phosphate (0.015 mg/l). During lobster farming activities feeding with trash fish for 270 days, we obtained daily growth rate of  0.74% (lower than normal growth rate of 0.86%), survival rate of 66% (lower than normal survival rate of 86.7%), and feed conversion ratio of 11.15. Ammonia was found as a dominant factor reducing growth  and survival rate of lobster reared in FNC.</em></p> <p><em> </em></p> <strong><em>Keywords:</em></strong><em> water quality, lobsters, growth, survival, Ekas Bay</em>

scholarly journals Tambaqui growth and survival when exposed to different photoperiods

2006 ◽  
Vol 36 (3) ◽  
pp. 381-384 ◽  
Author(s):  
Paulo Henrique Rocha Aride ◽  
Rodrigo Roubach ◽  
Sérgio Ricardo Nozawa ◽  
Adalberto Luís Val
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Continuous Light ◽  
Control Fish ◽  
Continuous Darkness ◽  
Growth And Survival ◽  
Colossoma Macropomum ◽  
Fish Weight ◽  
Natural Photoperiod

The use of different photoperiods (light) were investigated during tambaqui (Colossoma macropomum) juvenile growth under captivity. Light intensity tested was: continuous dark (24hrs without light), natural photoperiod simulation (10hrs of light and 14hrs without light) and continuous light (24 with light). No mortality was recorded among treatments. Significant differences was observed after 50 days of experiment among mean fish weight, fish kept under a continuous darkness showed a better specific growth rate (6.02%) when compared to control fish (natural photo period, 3.67%). Fish exposed to continuous light presented the lowest mean specific growth rate (2.04%). It is possible to improve tambaqui juvenile weight gain performance when kept under continuous darkness.

scholarly journals Variants in RNA-Seq data show a continued mutation rate during strain preservation of Schizophyllum commune

2017 ◽  
Author(s):  
Thies Gehrmann ◽  
Jordi F. Pelkmans ◽  
Luis G. Lugones ◽  
Han A.B. Wösten ◽  
Thomas Abeel ◽  
...  
Keyword(s):  
Mutation Rate ◽  
Schizophyllum Commune ◽  
Agar Plate ◽  
Protein Domain ◽  
Laboratory Model ◽  
Rna Seq ◽  
Spontaneous Mutations ◽  
Growth And Survival ◽  
In The Wild ◽  
The Impact

AbstractBackgroundTypical microorganism studies link genetic markers to physiological observations, like growth and survival. Experiments are carefully designed, comparing wildtype strains with knockout strains, and replications are conducted to capture biological variation. To maintain monoclonal strains, strain preservation systems are used to keep the number of generations between the primary stock and the experimental measurement low, to decrease the influence of spontaneous mutations on the experimental outcome. The impact of spontaneous mutations during the minimal number of growth cycles for the experimental design is, however, poorly studied.ResultsWe set out to characterize the mutation landscape using a transcriptomic dataset of Schizophyllum commune, a laboratory model for mushroom formation. We designed a methodology to detect SNPs from the RNA-seq data, and found a mutation rate of 1.923 10−8 per haploid genome per base per generation, highly similar to the previously described mutation rate of S. commune in the wild. Our results imply that approximately 300 mutations are generated during growth of a colony on an agar plate, of which 5 would introduce stop codons. Knock-outs did not incur an increase of mutations and chromosomal recombination occurring at mating type loci was frequent. We found that missense and nonsense SNPs were selected against throughout the experiment. Also, most mutations show a low variant allele frequency and appear only in a small part of the population. Yet, we found 40 genes that gained a nonsense mutation affecting one of its annotated protein domains, and more than 400 genes having a missense mutation inside an annotated protein domain. Further, we found transcription factors, metabolic genes and cazymes having gained a mutation. Hence, the mutation landscape is wide-spread and has many functional annotations.ConclusionsWe have shown that spontaneous mutations accumulate in typical microorganism experiments, where one usually assumes that these do not happen. As these mutations possibly confound experiments they should be minimized as much as possible, or, at least, be trackable. Therefore, we recommend labs to ensure that biological replicates originate from different parental plates, as much as possible.

scholarly journals Spread of infectious disease through clustered populations

2009 ◽  
Vol 6 (41) ◽  
pp. 1121-1134 ◽  
Author(s):  
Joel C. Miller
Keyword(s):  
Infectious Disease ◽  
Growth Rate ◽  
Significant Contribution ◽  
Dominant Factor ◽  
Disease Models ◽  
Minor Role ◽  
Rate Heterogeneity ◽  
A Minor ◽  
The Impact ◽  
Infectious Disease Models

Networks of person-to-person contacts form the substrate along which infectious diseases spread. Most network-based studies of this spread focus on the impact of variations in degree (the number of contacts an individual has). However, other effects such as clustering, variations in infectiousness or susceptibility, or variations in closeness of contacts may play a significant role. We develop analytic techniques to predict how these effects alter the growth rate, probability and size of epidemics, and validate the predictions with a realistic social network. We find that (for a given degree distribution and average transmissibility) clustering is the dominant factor controlling the growth rate, heterogeneity in infectiousness is the dominant factor controlling the probability of an epidemic and heterogeneity in susceptibility is the dominant factor controlling the size of an epidemic. Edge weights (measuring closeness or duration of contacts) have impact only if correlations exist between different edges. Combined, these effects can play a minor role in reinforcing one another, with the impact of clustering the largest when the population is maximally heterogeneous or if the closer contacts are also strongly clustered. Our most significant contribution is a systematic way to address clustering in infectious disease models, and our results have a number of implications for the design of interventions.

scholarly journals LAND USE CONVERSION: EVALUATION AND STRATEGIC ACTIONS

2017 ◽  
Vol 43 (1) ◽  
pp. 21-32
Author(s):  
Ruth Roselin Nainggolan
Keyword(s):  
Land Use ◽  
Swot Analysis ◽  
Agricultural Land ◽  
Management Strategies ◽  
Sample Selection ◽  
Dominant Factor ◽  
Private Land ◽  
Factors Affecting ◽  
Public Facilities ◽  
The Impact

The conversion of agricultural land  in Sumedang of  the  year  2005-2014 reached 317 hectares. The land generally converted  into housing, office buildings and public facilities. This study aims to conduct a comprenhensive  evaluation of the factors affecting changes in  land use, analyze the impact of the changes and develop management strategies. This research was conducted with a qualitative approach located in Sumedang District, West Java Province. Sampling was done by multistage random sampling. The first step is selection of the sample subdistricts purposively with consideration of subdistricts that convert of land use at most, they are: Sumedang Selatan, Jatinangor and Jatigede. The second step sample selection by simple random  to residents who do changes their agricultural land use. The data obtained from questionnaires, interviews,observations, study of documents and mass media. Working method is based on a modification of the stages of strategic planning for the company. Formulation of the strategy carried out through three phases: phase determination of the key internal and external factors, phase matching using the SWOT matrix, as well as the decision phase using QSPM matrix. The resulting strategy is implemented in a more technical work steps. The results showed the factors that affect farmers convert agricultural land is decreasing productivity of  the land, accretion of family members, the right of inheritance of land, high land prices, construction of public facilities and government policy. The most dominant factor affecting is different in each district. The impact of changes in land use in general is the opening of new agricultural land by cutting down forests, decline in rice productivity and the emergence of new unemployment and alteration or  loss of livelihood. From the SWOT analysis matrix, obtained three possible strategic options. First, a policy review of spatial and territories; second, to encourage farmers to maintain agricultural land by providing agricultural inputs and extension the use of organic materials to restore soil fertility and the third private land use change should be governed by strict licensing mechanism.

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