An Improved Method for Marking Crayfish

Crustaceana ◽  
1997 ◽  
Vol 70 (6) ◽  
pp. 641-652 ◽  
Author(s):  
Keyword(s):  
Population Size ◽  
Carapace Length ◽  
Field Studies ◽  
Pacifastacus Leniusculus ◽  
Practical Approach ◽  
Large Field ◽  
Improved Method ◽  
Field Sample ◽  
One Year ◽  
Remarkable Reduction

AbstractAn improved method of marking crayfish by refinement of punching holes in uropods and telson and clipping pleura was developed. The method, with at least 10 800 codes, provides an economical and practical approach to temporarily mark and individually identify crayfish, and is particularly useful for marking a large field sample. The method was tested by marking Pacifastacus leniusculus both in laboratory and river. The marks on the crayfish, ranging from 30 to 75 mm carapace length (CL), from the river lasted more than one year (or 2-3 moults). The table of 10 800 codes, in which most reliable codes are also indicated, is given to facilitate further application. The method is suitable for field studies on population size, density and dispersal or migration of animals as no significant effects on the survival of marked crayfish of >30 mm CL were found. However, care must be taken if the method is applied to estimate growth because a remarkable reduction (~20%) in the moult increment of CL after marking treatment was observed in crayfish, ranging from 33.4 to 46.6 mm CL, under laboratory conditions.

General practitioners and clinical pharmacology

1989 ◽  
Vol 4 (4) ◽  
pp. 241-244
Author(s):  
P. Lemoine
Keyword(s):  
Clinical Pharmacology ◽  
General Practitioners ◽  
Field Studies ◽  
Discussion Group ◽  
Group Method ◽  
Study Group ◽  
Test Drug ◽  
Monthly Basis ◽  
One Year ◽  
The One

SummaryIt is difficult to undertake field studies with non marketed psychotropic drugs because of two apparently contradictory conditions : on the one hand, the methodology has to be rigorously controlled, and on the other hand, such studies have to be carried out in their future environment by general practitioners (GPs). Bearing in mind the lack of training and experience regarding this kind of approach, the author adopted a discussion group method according to the techniques developed by M. Balint. The study group comprised five GPs, a clinical pharmacology expert and a doctor from the pharmaceutical laboratory which had developed the test drug. These persons met on a monthly basis over a one year period. In the present paper, the author indicates the benefits of such a methodology, based on six years’ experience and several trials, with special emphasis placed on the pedagogical aspects.

Biennial Reproductive Cycle of Blue King Crab, Paralithodes platypus, at the Pribilof Island, Alaska and Comparison to a Congener, P. camtschatica

1989 ◽  
Vol 46 (6) ◽  
pp. 932-940 ◽  
Author(s):  
Gregory C. Jensen ◽  
David A. Armstrong
Keyword(s):  
Carapace Length ◽  
Reproductive Output ◽  
Size Range ◽  
Egg Mass ◽  
King Crab ◽  
Pribilof Island ◽  
Blue King Crab ◽  
Paralithodes Platypus ◽  
One Year ◽  
Reproductive Events

Pribilof Island blue king crab (BKC; Paralithodes platypus) were sampled by beam trawl in May and August of 1983 and April 1984 to determine timing of reproductive events. Biennial reproduction was found to be the result of slow ovarian growth in large, muciparous females, while smaller primiparous females are often able to spawn in two consecutive years. Mating and egg extrusion occur in late March to early May and eggs hatch in mid-April of the following year, consequently, the embryonic period and rate of development is approximately 12 mo, similar to that of its congener the red king crab (RKC; P. camtschatica). Comparison of the reproductive output of the two species revealed that despite the 2 yr ovarian cycle, BKC only produce 20–30% more dry egg mass at any carapace length than do RKC, a substantially smaller difference than previously calculated. One year after molt, females of both species are not significantly different in dry body weight over a size range of 100–140 mm carapace length, but RKC have produced about three times more dry ovarian weight than BKC of comparable size, suggesting that biennial reproduction in BKC may be the result of energetic limitations.

scholarly journals Challenges of ecological monitoring: estimating population abundance from sparse trap counts

2011 ◽  
Vol 9 (68) ◽  
pp. 420-435 ◽  
Author(s):  
Natalia Petrovskaya ◽  
Sergei Petrovskii ◽  
Archie K. Murchie
Keyword(s):  
Population Size ◽  
Numerical Integration ◽  
Spatial Data ◽  
Population Distribution ◽  
Species Abundance ◽  
Ecological Monitoring ◽  
Field Studies ◽  
Pest Species ◽  
Population Size Estimates ◽  
Size Estimates

Ecological monitoring aims to provide estimates of pest species abundance—this information being then used for making decisions about means of control. For invertebrate species, population size estimates are often based on trap counts which provide the value of the population density at the traps' location. However, the use of traps in large numbers is problematic as it is costly and may also be disruptive to agricultural procedures. Therefore, the challenge is to obtain a reliable population size estimate from sparse spatial data. The approach we develop in this paper is based on the ideas of numerical integration on a coarse grid. We investigate several methods of numerical integration in order to understand how badly the lack of spatial data can affect the accuracy of results. We first test our approach on simulation data mimicking spatial population distributions of different complexity. We show that, rather counterintuitively, a robust estimate of the population size can be obtained from just a few traps, even when the population distribution has a highly complicated spatial structure. We obtain an estimate of the minimum number of traps required to calculate the population size with good accuracy. We then apply our approach to field data to confirm that the number of trap/sampling locations can be much fewer than has been used in many monitoring programmes. We also show that the accuracy of our approach is greater that that of the statistical method commonly used in field studies. Finally, we discuss the implications of our findings for ecological monitoring practice and show that the use of trap numbers ‘smaller than minimum’ may still be possible but it would result in a paradigm shift: the population size estimates should be treated probabilistically and the arising uncertainty may introduce additional risk in decision-making.

The effect of temperature on the field softening of hard seed of Stylosanthes humilis and S. hamata in a dry monsoonal climate

1982 ◽  
Vol 33 (1) ◽  
pp. 75 ◽  
Author(s):  
GM McKeon ◽  
JJ Mott
Keyword(s):  
Management Practices ◽  
Soil Surface ◽  
Field Studies ◽  
Effect Of Temperature ◽  
Maximum Temperature ◽  
Hard Seed ◽  
Surface Temperatures ◽  
Stylosanthes Humilis ◽  
One Year ◽  
Field And Laboratory Conditions

The changes in hard-seed content in pastures of Stylosanthes humilis and S. hamata cv. Verano were studied at Katherine, N.T. Both field studies and laboratory ovens with diurnal temperature changes showed that maximum soil surface temperatures greater than 50-55�C were required to produce substantial softening of hard seed. The rate of softening increased with higher maximum temperature. At Katherine, only the September-November period (late dry season) was likely to produce soil surface temperatures high enough for softening in naturally occurring seed populations. S. hamata did not soften to the same extent as S. humilis under both field and laboratory conditions. In established pastures only 35 % of S. hamata seed softened in one year, compared with 60-80% in S. humilis. Management practices may be required to improve seedling regeneration or establishment of new pastures in S. hamata.

Field Studies on the Behaviour of Organic Micropollutants During Infiltration of River Water to Ground Water

1987 ◽  
Vol 19 (7) ◽  
pp. 1195-1196 ◽  
Author(s):  
C. Schaffner ◽  
M. Ahel ◽  
W. Giger
Keyword(s):  
Ground Water ◽  
River Water ◽  
Chlorinated Solvents ◽  
Field Studies ◽  
Water Infiltration ◽  
Organic Micropollutants ◽  
Field Site ◽  
Phenolic Pollutants ◽  
One Year ◽  
Observation Wells

The fate of organic micropollutants during ground water infiltration is of great interest since many water works use bank filtration as a first step in the treatment of river water for public water supplies. Field and laboratory studies are necessary to enhance our knowledge on the behaviour of organic chemicals during infiltration of river water to ground water. In an earlier study nonpolar volatile compounds (e.g. tetrachloroethylene, 1,4-dichlorobenzene and 1,3-dimethylbenzene) were investigated in natural river-ground water infiltration systems in Switzerland (Schwarzenbach et al., 1983). In this poster we report on recent work using one of these field sites and studying pentachlorophenol (PCP), nonylphenol (NP), nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO) and nitrilotriacetate (NTA), Preliminary results will also be reported for ethylenediaminetetraacetate (EDTA) and polycyclic aromatic hydrocarbons. The field site for our investigation was in the lower Glatt Valley, Switzerland where the Glatt River infiltrates into a quarternary fluvioglacial valley fill aquifer. The Glatt River is a small, rather heavily polluted perialpine river which receives effluents from ten mechanical-biological treatment plants of municipal waste water (Ahel et al., 1984). At the field site the average discharge of the river is approximately 8 m3/sec and permanent infiltration of the river through a saturated zone can be assumed. Observation wells allowed the sampling of freshly infiltrated water at various distances (2,5 - 14 m) from the river. During one year seventeen sample series were collected at approximately monthly intervals including samples from the river and from four ground water observation wells. Pentachlorophenol was determined by a method based on the procedure by Renberg and Lindstróm (1981), Detailed descriptions of the analytical methods for NP, NP1EO, NP2EO and NTA are given elsewhere (Ahel and Giger, 1985; Schaffner and Giger, 1984). The observed averages and ranges of concentrations are given in Table 1. It was concluded that NTA is eliminated rapidly during ground water infiltration. Starting from a range of 8 to 83 mg/m3 and an average of 27 mg/m3 in the river, after 7 m of infiltration only 0.5 mg/m3 are left corresponding to an elimination of 98%. Low temperatures in winter (4 – 6 °C) and reduced oxygen contents in summer had no effect on the efficient elimination of NTA, This result is highly important in addressing the question as to what extent NTA might reach bank filtrated waters from polluted rivers. The phenolic pollutants were eliminated according to the sequence: NP1EO ≈ NP2EO > NP > PCP. This is based on the decrease of the average concentrations over the first seven meters of infiltration. In particular, PCP turned out to be rather persistent in the ground water but not to such a degree as tetrachloroethylene and other chlorinated solvents which had been studied earlier.

Response of flax and lentil to seeding rates, depths and spring application of dinitroanaline herbicides

1994 ◽  
Vol 74 (4) ◽  
pp. 875-882 ◽  
Author(s):  
D. A. Wall
Keyword(s):  
Population Density ◽  
Seed Yield ◽  
Linum Usitatissimum ◽  
Field Studies ◽  
Test Weight ◽  
Seeding Rate ◽  
Population Densities ◽  
Herbicide Treatment ◽  
Herbicide Treatments ◽  
One Year

Two field studies were conducted at Morden, Manitoba in 1992 and 1993 to investigate the effect of seeding depth and seeding rate on flax and lentil recovery following spring application of dinitroanaline herbicides. In the first study, the effect of seeding depth on flax and lentil tolerance to ethalfluralin, pendimethalin and trifluralin, applied preplant soil incorporated at 1.1 kg a.i. ha−1 in the spring, was investigated. Deep seeding (6 cm) reduced flax population density by 59%, averaged over 2 yr, when compared with shallow seeding (3 cm). Ethalfluralin, pendimethalin and trifluralin, reduced flax population density, but the effect of herbicide was less when flax was seeded shallow. Trifluralin and ethalfluralin reduced flax yield more when the crop was seeded deep than when seeded shallow. Herbicide treatments had no effect on flax yield when the crop was seeded shallow. Ethalfluralin and trifluralin reduced lentil population density and seed yield in one year only. Pendimethalin did not reduce lentil population density or seed yield. Deep seeding did not affect lentil population density, seed yield or phytotoxicity of dinitroanalines in this crop. In a second study, flax and lentil were seeded at 15, 30, 45, 60 and 90 kg ha−1 at 3 and 6 cm planting depths to assess the effect of seeding depth and seeding rate on crop recovery following spring application of ethalfluralin. In ethalfluralin treated plots, seeding rate had to be increased from 60 to > 90 kg ha−1 to achieve similar population densities as 45 kg ha−1 in untreated plots. Flax yields were unaffected by ethalfluralin when the crop was seeded shallow, but yields were reduced significantly when the crop was seeded deep. Lentil population density increased linearly with seeding rate. Lentil population density was unaffected by seeding depth or herbicide treatment. Ethalfluralin did not reduce lentil yield in either year. Lentil yields increased with seeding rate up to 30 kg ha−1, with little further increase in yield for seeding rates between 30 and 90 kg ha−1. Key words:Lens culinaris, Linum usitatissimum, population density, seeding depth, seeding rate, yield, seed test weight, ethalfluralin, pendimethalin, trifluralin

scholarly journals 993 THEORY AND APPLICATION OF GENETIC ENGINEERING FOR STRESS RESISTANCE AND AVOIDANCE

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 571d-571
Author(s):  
Steven E. Lindow
Keyword(s):  
Population Size ◽  
Pseudomonas Syringae ◽  
Stress Resistance ◽  
Field Studies ◽  
Ice Nucleation ◽  
Site Directed Mutagenesis ◽  
Ice Formation ◽  
Bacterial Strains ◽  
Solanum Commersonii ◽  
Frost Injury

Genes determining the ability of the bacterium Pseudomonas syringae to catalyze ice formation have been cloned and characterized. Ice nucleation active (Ice+) strains of this species are common on plants and the supercooling ability of frost sensitive plants is inversely proportional to the logarithm of the population size of Ice+ bacteria at temperatures above -5C. Recombinant Ice- derivatives off. syringae were produced by site-directed mutagenesis using deletion containing ice genes cloned form this species. The Ice- strains colonized potatoes well in field studies, reduced the population size of Ice+ bacterial strains by about 50-fold, and reduced the incidence of frost injury an average of 82% in several radiative frosts of temperatures in the range of -3 to -5 C. The ice gene has also been introduced into Solanum commersonii to determine its effect on increasing the tolerance of ice formation in this frost tolerant species. Transgenic plants exhibit a much higher threshold ice nucleation temperature than the parental plants.

scholarly journals Relative growth of freshwater prawn Macrobrachium brasiliense (Decapoda, Palaemonidae) and its implications for reproduction

2019 ◽  
Vol 109 ◽  
Author(s):  
Caio dos Santos Nogueira ◽  
Marcela Silvano de Oliveira ◽  
Giuliano Buzá Jacobucci ◽  
Ariádine Cristine de Almeida
Keyword(s):  
Sexual Dimorphism ◽  
Sexual Maturity ◽  
Carapace Length ◽  
Freshwater Prawn ◽  
Relative Growth ◽  
Guarding Behavior ◽  
Males And Females ◽  
One Year ◽  
Almost All

ABSTRACT The main objective of this study was to estimate the morphological sexual maturity of Macrobrachium brasiliense (Heller, 1862) and to analyze the relative growth of the species. During one year of sampling, from July 2012 to June 2013, 199 specimens were collected in a stream located in a Cerrado biome, in the Triângulo Mineiro region, state of Minas Gerais. Once identified and sexed, the length of the carapace, the length of the segments of the chelipeds (ischium, merus, carpus, propodus and dactyl) and width of the pleura were measured (mm). The maximum and mean sizes of the carapace length measured 20.5 mm (Mean: 9.6 ± 4.2 mm) and 20.1 mm (Mean: 7.7 ± 3.4 mm) for males and females, respectively. The propodus length for males, and the pleura width for females, were used for the classification of the specimens into juvenile and adult, using K-means analysis and discriminant analysis. The relative growth of the species was also evaluated through covariance analysis for all structures (ANCOVA, α = 0.05). In females, the growth of most structures occurred equally between juveniles and adults, with the exception of the merus and pleura structures. On the other hand, the growth of almost all structures of males differed between juveniles and adults. Only the carpus and the pleura growth were similar. We also estimated the size at onset of morphological sexual maturity at 8.64 mm CL for males (CL50% r = 1.71) and 8.03 mm CL for females (CL50% r = 0.07). Our results contribute to the understanding of some important questions related to the reproductive biology of M. brasiliense. We noted that males grow differently from females and become the largest individuals in the population, resulting in a sexual dimorphism. Such sexual dimorphism might promote the development of the temporary mating guarding behavior, a reproductive strategy very important for caridean shrimps.

scholarly journals Monthly Entomological Inoculation Rate Data for Studying the Seasonality of Malaria Transmission in Africa

Data ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 31
Author(s):  
Edmund I. Yamba ◽  
Adrian M. Tompkins ◽  
Andreas H. Fink ◽  
Volker Ermert ◽  
Mbouna D. Amelie ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Entomological Inoculation Rate ◽  
Auxiliary Information ◽  
Central Africa ◽  
Field Studies ◽  
Field Surveys ◽  
Comprehensive Literature Review ◽  
West And Central Africa ◽  
Specific Standard ◽  
One Year

A comprehensive literature review was conducted to create a new database of 197 field surveys of monthly malaria Entomological Inoculation Rates (EIR), a metric of malaria transmission intensity. All field studies provide data at a monthly temporal resolution and have a duration of at least one year in order to study the seasonality of the disease. For inclusion, data collection methodologies adhered to a specific standard and the location and timing of the measurements were documented. Auxiliary information on the population and hydrological setting were also included. The database includes measurements that cover West and Central Africa and the period from 1945 to 2011, and hence facilitates analysis of interannual transmission variability over broad regions.

A Training Program for Operators of Small Wastewater Treatment Plants

1993 ◽  
Vol 28 (10) ◽  
pp. 43-48
Author(s):  
K. D. Kerri
Keyword(s):  
Wastewater Treatment ◽  
Training Program ◽  
Treatment Process ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Field Studies ◽  
Training Materials ◽  
Extensive Field ◽  
One Year ◽  
Self Instruction

Operators of small wastewater treatment plants frequently live in remote areas where operator training is not readily available. A training program has been prepared using the techniques of self-instruction, wherein an operator reads a short section of the training material, writes the answers to questions in a notebook, and compares the written answers with suggested answers. The training materials were developed by experienced operators following extensive field studies. First, operators (subject matter experts) for each treatment process prepared an outline of what knowledge and skills (need-to-know criteria) they expected their operators to possess to safely operate and maintain each treatment process in the training manual. Draft chapters were then field tested using operators with varying levels of education and experience to determine the effectiveness of the training materials. Studies conducted on the performance of operators who had participated in the training program and those who had not received the training revealed that trained operators produced a better quality effluent at the same treatment plant over a one-year period. Effective training materials and programs can help operators safely and efficiently operate and maintain small wastewater treatment plants.

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