Mixed-Species Yield-per-Recruit Simulations of the Effect of Seasonal Closure on a Central Queensland Coastal Prawn Trawling Ground

1994 ◽  
Vol 51 (5) ◽  
pp. 998-1011 ◽  
Author(s):  
N. Gribble ◽  
M. Dredge
Keyword(s):  
Field Studies ◽  
Fishing Mortality ◽  
Economic Gain ◽  
Mixed Species ◽  
Direct Benefit ◽  
Reduced Costs ◽  
Effect On Yield ◽  
Yield Per Recruit ◽  
Positive Effect ◽  
Logbook Data

An assessment of the effect of seasonal closure on the central Queensland coastal prawn trawling grounds was carried out by mixed-species yield-per-recruit simulations of the fishery based on parameters determined from field studies and analysis of logbook data. Under a conventional scenario of constant fishing mortality, simulations suggest little positive effect on yield to be achieved from closures of up to 15 wk in duration. Economic gain would have to be made via reduced costs during the closure, rather than through increased value of the postclosure yield. Logbook data clearly showed that the fishery underwent a heavy pulse of effort, immediately after the fishing season opened. Nonlocal boats had entered the fishery to take advantage of the prawns available. Using this more realistic regime of fishing mortality, simulations suggest a significant increase in yield and value of catch. The increase was caused by boosted exploitation rates of the stocks and was determined by the magnitude of the effort pulse rather than as a direct benefit of the closure.

Spatial variation in fishing intensity and its effect on yield

2008 ◽  
Vol 65 (4) ◽  
pp. 588-599 ◽  
Author(s):  
Stephen Ralston ◽  
Michael R O’Farrell
Keyword(s):  
Spatial Variation ◽  
Local Density ◽  
Life Stage ◽  
Maximum Sustainable Yield ◽  
Recruitment Rate ◽  
Sustainable Yield ◽  
Fishing Mortality ◽  
Density Dependent ◽  
Age Structured ◽  
Effect On Yield

Fishing mortality is rarely, if ever, evenly distributed over space, yet this is a common assumption of many fisheries models. To evaluate the effect of spatial heterogeneity in fishing mortality on yield, we constructed age-structured models that allowed for differing levels of fishing in three regions within the boundaries of a stock and explored alternative assumptions about the life stage in which density-dependent compensation operates. If the fishing mortality rate (F) is not excessive (i.e., F ≤ FMSY defined for the spatially homogeneous case; MSY, maximum sustainable yield), simulations demonstrated that minor to moderate spatial variation in fishing intensity does not impact sustainable yield. However, if fishing mortality is excessive (F > FMSY), spatial variation in fishing intensity often improves yield and can actually produce yields in excess of MSY when compensation occurs after dispersal, and the density-dependent recruitment rate is a function of the local density of adults. The yield premium generated in these simulations by postdispersal density dependence is due to a low level of compensatory mortality in heavily fished areas coupled with dispersal of propagules into these areas from lightly fished adjacent regions.

Agronomic evaluation of a tiller inhibition gene (tin) in wheat. I. Effect on yield, yield components, and grain protein

2005 ◽  
Vol 56 (2) ◽  
pp. 169 ◽  
Author(s):  
B. L. Duggan ◽  
R. A. Richards ◽  
A. F. van Herwaarden ◽  
N. A. Fettell
Keyword(s):  
Triticum Aestivum L ◽  
Kernel Weight ◽  
Grain Protein ◽  
Terminal Drought ◽  
Spike Number ◽  
Effect On Yield ◽  
Productive Tiller ◽  
Wheat Lines ◽  
Positive Effect ◽  
Yield Penalty

Reduced tillering cereals have been proposed as being advantageous under terminal drought conditions through their reported reduction in non-productive tiller number and reduced soil water use prior to anthesis. This study was conducted to determine whether wheat (Triticum aestivum L.) lines containing the tiller inhibition (tin) gene have a yield penalty over their commercial near-isogenic counterparts. A terminal drought was experienced in all experiments. The effects of the tin gene were investigated in 4 different near-isogenic pairs of lines grown at 2 sowing densities at 4 locations in the eastern Australian wheatbelt over a 3-year period. Averaged over all experiments and lines, grain yield was unaffected by the presence of the tin gene. However, the highest yielding line contained the tin gene and its yield was 5% higher than all other lines. Averaged across the different genetic backgrounds, the tin gene decreased fertile spike number by 11%, increased the number of kernels/spike by 9%, and there was a 2% increase in kernel weight. The tin gene increased the harvest index by an average of 0.02, whereas above-ground biomass was reduced by 7%. Increasing sowing density from 50 to 100 kg/ha had little influence on yield or yield-related characteristics in both the restricted tillering and freely tillering lines. There was an interaction between sowing rate and the presence of the tin gene on yield, with tin lines yielding 0.2 t/ha more than the freely tillering lines at the higher sowing rate, whereas there was no effect at the lower sowing rate. The response of several lines containing the tin gene to nitrogen fertiliser was also investigated at 2 sites. Nitrogen increased spike number in all lines but the number remained around 20% less than in the freely tillering cultivars. The yield of wheat lines containing the tin gene was 6% greater than their near-isogenic pairs where nitrogen status was high in the presence of terminal drought. Grain protein concentration was unaffected by the presence of the tin gene at high grain protein sites, whereas at lower grain protein sites it had a positive effect.

An Alternative Perspective on Recruitment Overfishing and Biological Reference Points

1987 ◽  
Vol 44 (4) ◽  
pp. 913-918 ◽  
Author(s):  
M. P. Sissenwine ◽  
J. G. Shepherd
Keyword(s):  
Fisheries Management ◽  
Reference Point ◽  
Reference Points ◽  
Fishing Mortality ◽  
Alternative Perspective ◽  
Conventional Models ◽  
Definition Of ◽  
Yield Per Recruit ◽  
Spawning Biomass

Biological reference points are used to guide fisheries management decisions. The reference points most often used are expressed in terms of fishing mortality rate (F). Fmsy relates to the maximization of sustainable yield. In principle, it is a most useful reference point, but in practice it is difficult to estimate. Fmax and F0.1 relate to certain levels of yield per recruit and are easily estimated, but they ignore conservation of the resource. Recruitment overfishing has usually been understood to occur when a population has been fished down to a point where recruitment is substantially reduced or fails. It has not been used as a basis for a biological reference point because the definition is vague and cannot be readily related to fishing mortality. Levels of spawning biomass below which recruitment seems to be reduced have been used, but their determination from available data is usually difficult and controversial. We propose an alternative definition of recruitment overfishing in terms of the level of fishing pressure that reduces the spawning biomass of a year class over its lifetime below the spawning biomass of its parents on average. Conventional models and types of data can be used to determine this level of F, denoted as Frep, which clearly relates to the replacement of spawning biomass and thus to sustainability of a population and yield in the long term.

scholarly journals Split fertilization as a strategy to reduce the amount of fertilizer applied in potato crops form Colombia. Case of study

2020 ◽  
Vol 14 (2) ◽  
pp. 240-248
Author(s):  
Oscar Iván Monsalve ◽  
Eduardo María Espitia ◽  
Martha Marina Bolaños-Benavides
Keyword(s):  
Soil Fertility ◽  
Potato Plant ◽  
Split Application ◽  
Potato Plants ◽  
Low Efficiency ◽  
Effect On Yield ◽  
Potato Crops ◽  
Positive Effect

In potato crops in Colombia, fertilization has low efficiency in terms of absorption of nutrients by the plant due to fixing, leaching or volatilization processes. To counter this phenomenon, we evaluated the effect of the split application of fertilizers on potato plants and soil. Five treatments were evaluated: Control - fertilization used by farmers locally; As - fertilization recommended by the lab; AsSplit - monthly split of lab recommendation; AsSplit25 - monthly split of lab recommendation, reduced globally by 25%; AsSplit50 - monthly split of the lab recommendation, reduced globally by 50%. AsSplit treatment generated the highest yield (34.13 t ha-1), while treatments that reduced the amount of fertilizer by 25% and 50% obtained the lowest yield (30.94 and 29.57 t ha-1, respectively). However, they generated the lowest amount of NO3- in the leachate measurements at 30 and 90 cm deep. Our results suggest that designing the fertilization formula and applying it according to the requirements of the potato plant and soil fertility generates a positive effect on yield crop and environmental.

scholarly journals Influence of Planting Systems and Feeding Regimes on Dry Mass Accumulation of Cotton

2021 ◽  
Vol 9 (12) ◽  
pp. 1196-1198
Author(s):  
Jalilov Lutfiyor Sotvoldievich
Keyword(s):  
Dry Mass ◽  
Cattle Manure ◽  
Root Activity ◽  
Feeding Regimes ◽  
Effect On Yield ◽  
Positive Effect ◽  
Mass Accumulation

Annotation: In order to increase the organic biomass in a bush, at least 15 t / ha of semi-rotted cattle manure before plowing, if possible plowed to 30 t / ha in autumn and then sowing in spring, retains the ability to absorb root activity longer, which has a positive effect on yield. reaches

scholarly journals TOPLAM KALİTE YÖNETİMİNİN İŞGÖREN PERFORMANSINA ETKİLERİ: TEKSTİL İŞLETMELERİ ÜZERİNE BİR ARAŞTIRMA

2018 ◽  
Vol 6 (3) ◽  
Author(s):  
Ergün KARA
Keyword(s):  
Quality Management ◽  
Total Quality Management ◽  
Total Quality ◽  
Economic Gain ◽  
Face To Face ◽  
Correlation And Regression Analysis ◽  
Career Opportunities ◽  
Personal Skills ◽  
Positive Effect ◽  
Textile Sector

Total quality management is a management perception which has to increase quality and productivity in managements of all opportunities mobilised systematically to provide client satisfaction. To reach success in total quality management (TQM) perception depends on various reasons so satisfying the employees' request and expectations is quite essential for this success.  For this reason, providing increase of the employees' economic income in management gain parallel, increasing their motivation, presenting career opportunities to prove themselves, taking performance increase precautions and using awarding systems are necessary factors for TQM success.  The effect of total quality management which is practised in the sectors such as textile sector especially which requires employees' personal skills was researched on the basic factors which affects employees' performance.  The research was done by face to face technique with 275 staff working in textile managements in Bursa province.  In the conclusion of correlation and regression analysis, it was determined that total quality management has a positive effect on the employees' economic gain and motivation.

scholarly journals Potassium Fertigation to Enhance the Performance of Hypoxis hemerocallidea

HortScience ◽  
2021 ◽  
pp. 1-9
Author(s):  
Patience Seyram Akakpo ◽  
Moosa Mahmood Sedibe ◽  
Bello Zaid ◽  
Zenzile P. Khetsha ◽  
Mokgaputsiwa P. Theka-Kutumela ◽  
...  
Keyword(s):  
Nutrient Solution ◽  
Analysis Data ◽  
Dry Mass ◽  
Ionic Balance ◽  
Fresh Weight ◽  
Primary Metabolite ◽  
Essential Nutrient ◽  
Effect On Yield ◽  
Metabolite Content ◽  
Positive Effect

Potassium (K) is an essential nutrient in plant metabolism, ionic balance, and stress resistance. In this study, the effects of K on agronomic attributes and on mineral and primary metabolite content in African potato were determined. K was administered hydroponically at four concentrations (4.00, 6.00, 8.00, and 10.00 meq·L−1) using Steiner’s universal nutrient solution. Chlorophyll content (CHL), leaf area (LA), fresh corm mass (FCM), number of roots (NR), root fresh weight (RFM), and root dry mass (RDM) were measured 18, 32, and 40 weeks after transplanting. Mineral analysis data were collected at 18 weeks, and primary metabolite data were collected at 32 weeks. Significant effects of K were observed after 18 weeks, and all test concentrations had a positive effect on yield. Calcium and boron significantly accumulated in the corm at 4.00 meq·L−1 K. Alanine and malic acid were the only metabolites affected by K concentrations. More minerals accumulated in the corm at 4.00 meq·L−1 K, whereas at 10.00 meq·L−1 K, more minerals clustered in the leaf. K applied at 4.00 meq·L−1 is recommended when growing African potato using a nutrient solution to improve corm mineral and metabolite accumulation.

Finding new QTL for yield traits based on a high-density genetic map in the super hybrid rice Nei2You No.6

2019 ◽  
Author(s):  
Miao Zhang ◽  
Zhengping Zhou ◽  
Yuyu Chen ◽  
Yongrun Cao ◽  
Chenwei Deng ◽  
...  
Keyword(s):  
Complex Traits ◽  
Yield Components ◽  
Average Density ◽  
High Density ◽  
Yield Traits ◽  
Target Region ◽  
Effect On Yield ◽  
Positive Effect ◽  
High Density Linkage Map ◽  
1000 Grain Weight

Abstract Background Rice is one of the most important food crops in the world. To determine the genetic basis of yield components in super rice Nei2You No.6, 387 recombinant inbred sister lines (RISLs) were obtained for mapping quantitative trait loci (QTL) responsible for yield-associated traits, such as 1000-grain weight (TGW), grain number per plant (GNP), number of panicles per plant (NP), and grain yield per plant (GYP). Results Using whole genome re-sequencing, a high-density linkage map consisting of 3203 bin markers was constructed with total genetic coverage of 1951.1 cM and an average density of 0.61 cM. As a result of the multi-environment test, 43 yield-related QTL were mapped to all 12 chromosomes, among which 28 inherited from Nei2B showed a positive effect on yield traits. Nine QTL, qTGW-1a, qTGW-5, qTGW-7, qTGW-10b, qTGW-10c, qTGW-12, qNP-7, qGNP-6c, and qGYP-6b, showed stable effects across multiple environments. Five of the nine QTL were co-located with previously reported QTL, and four novel loci, qTGW-7, qTGW-12, qGNP-6c, and qNP-7, were identified in the present study. Subsequently, qNP-7, qTGW-12, and qTGW-7 were validated using corresponding paired lines which differed only in the target region. Conclusions the RISL population is an effective tool for mapping and validating QTL of complex traits, for instance, yield-associated traits, and newly detected QTL provide new genetic resources for research of yield components and molecular breeding in rice.

scholarly journals Peanut Cultivar Response to Flumioxazin Applied Preemergence and Imazapic Applied Postemergence

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
W. J. Grichar ◽  
P. A. Dotray ◽  
M. R. Baring
Keyword(s):  
Field Studies ◽  
Herbicide Treatments ◽  
Effect On Yield

Field studies were conducted during 2009 and 2010 in Texas at Yoakum and Lamesa to determine peanut cultivar response to flumioxazin applied preemergence (0.053, 0.107, and 0.214 kg ai ha−1) and imazapic applied postemergence (0.035, 0.071, and 0.141 kg ai ha−1). At Yoakum, two cultivars (Tamrun OL01, Tamrun OL07) were evaluated while at Lamesa, four cultivars (FlavorRunner 458, Tamrun OL01, Tamrun OL02, and Tamrun OL07) were evaluated. In 2009, no stunting was noted at Yoakum with any herbicide regardless of cultivar. At Lamesa, FlavorRunner 458 and Tamrun OL01 were stunted at least 6% with the 0.21 kg ha−1rate of flumioxazin and 6 to 17% with the 0.07 and 0.14 kg ha−1rate of imazapic. Tamrun OL02 was stunted by all rates of flumioxazin (5%) and imazapic (5 to 18%) while Tamrun OL07 was stunted by all rates of flumioxazin (6 to 12%) and imazapic (7 to 15%) with the exception of flumioxazin at 0.05 kg ha−1. Flumioxazin did not have an effect on yield while all imazapic rates reduced yields when compared with the non-treated control. In 2010 at Yoakum, little (<2%) or no herbicide stunting was noted on any cultivar and only imazapic at 0.14 kg ha−1caused significant stunting (7%). No yield differences were noted between herbicides regardless of cultivar. At Lamesa, all cultivars were affected (6 to 9% stunting) by herbicide treatments. No peanut stunting was noted with flumioxazin at 0.05 kg ha−1while imazapic at 0.04 kg ha−1and flumioxazin at 0.11 kg ha−1resulted in 4 and 6% stunting, respectively. Flumioxazin at 0.21 kg ha−1and imazapic at 0.07 kg ha−1resulted in 12% stunting and imazapic at 0.14 kg ha−1stunted peanut 19%. Both Tamrun OL01 and Tamrun OL07 produced lower yields (≤6369 kg ha−1) than FlavorRunner 458 (7252 kg ha−1). Tamrun OL02 yields were intermediate (6889 kg ha−1). Peanut yields from herbicide treatments were not different from the non-treated control.

Volunteer Barley (Hordeum vulgare) Interference in Canola (Brassica campestrisandB. napus)

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 734-739 ◽  
Author(s):  
John T. O'Donovan ◽  
Arvind K. Sharma ◽  
Ken J. Kirkland ◽  
E. Ann De St. Remy
Keyword(s):  
Hordeum Vulgare ◽  
Yield Loss ◽  
Field Studies ◽  
Yield Potential ◽  
Western Canada ◽  
Effect On Yield ◽  
Financial Losses ◽  
Barley Crop

The yield potential and the effect on yield loss of canola of different densities of volunteer barley were investigated at three locations in western Canada. Field studies were conducted from 1982 to 1986. Rectangular hyperbolic models based on data pooled over years, locations, and canola cultivars, and incorporating different densities of volunteer barley and canola accurately portrayed field responses in most instances. Results indicated that volunteer barley severely reduced canola yield. However, financial losses due to reduced canola yield were partly offset by the volunteer barley crop.

Sign in / Sign up

Export Citation Format

Share Document