Croissance et production du bivalve Mesodesma arctatum (Conrad) sur la côte nord du golfe du Saint-Laurent

1986 ◽  
Vol 64 (9) ◽  
pp. 1914-1919 ◽  
Author(s):  
Jean-Claude F. Brêthes ◽  
Gaston Desrosiers ◽  
Gilles Fortin Jr.
Keyword(s):  
Dry Weight ◽  
Reproductive Period ◽  
Subtidal Zone ◽  
Growth Equation ◽  
Total Production ◽  
Age At First Reproduction ◽  
The North ◽  
Theoretical Evolution ◽  
Somatic Production ◽  
Von Bertalanffy Growth Equation

Samples of Mesodesma arctatum (Pelecypoda) were collected during the summer of 1983 in the subtidal zone of the Saint-Jean River delta, on the north shore of the Gulf of St. Lawrence. Age was estimated by counting successive growth lines. Maximum longevity was estimated to be about 24 years. The von Bertalanffy growth equation was Lt = 48.1 (1−e−0,23(t−0,53)) mm. The instantaneous mortality rate was 0.26, estimated from a log regression of abundance versus age. The theoretical evolution of a single cohort was calculated; according to the model, biomass, expressed in dry weight, reached its maximum at 6 years and the ratio of somatic production to biomass was estimated to be 0.27. The age at first reproduction is between 3 and 4 years. The reproductive period seems to be during July. The reproductive effort was calculated from the weight difference between the reproductive and postreproductive periods and was determined to be 47% of the total production of the cohort.

Modeling of ecological conditions in the Euxine Basin in the Sarmatian and Maeotian by methods of diatom analysis

2019 ◽  
pp. 257-261
Author(s):  
Eleonora P. Radionova
Keyword(s):  
Black Sea ◽  
Late Miocene ◽  
The Black Sea ◽  
Subtidal Zone ◽  
Diatom Analysis ◽  
Diatom Flora ◽  
North West ◽  
Ecological Conditions ◽  
The North

The associations and ecological conditions of the existence of modern diatoms of the North-West (Pridneprovsky), Prikerchensky and Eastern regions of the subtidal zone of the Black Sea are considered. Based on the unity of the composition of the Present and Sarmatian-Meotian diatom flora, an attempt has been made to model some of the ecological c situation of the Late Miocene Euxinian basin.

Age and growth pattern of the thin-lipped mullet Liza Ramada in the Eastern coast of Libya.

2016 ◽  
Vol 5 (06) ◽  
pp. 4620
Author(s):  
Manal M. Khalifa ◽  
Ramadan A. S. Ali ◽  
Abdalla N. Elawad* ◽  
Mohammad El. ElMor
Keyword(s):  
Frequency Distribution ◽  
Age Groups ◽  
Age Determination ◽  
Age And Growth ◽  
Eastern Coast ◽  
Growth Equation ◽  
Length Frequency Distribution ◽  
Length Frequency ◽  
Scale Reading ◽  
Von Bertalanffy Growth Equation

Age and growth characteristics of the thin-lipped Grey Mullet (Liza ramada) were investigated in Eastern coast of Libya. Aging was done by two methods: counting annuli on scales and by length frequency distribution, a total of 218 scales were studied for age determination, in addition of 334 fishes specimen for length frequency distribution reading. Four age groups were determined from scale reading, and five age groups from length frequency distribution methods, the parameters of the Von Bertalanffy growth equation for both sex of all individuals were estimated at 35.4 cm, 0.187 per year, -1.14 years and 2.4, for male were estimated at 35.7 cm, 0.17 per year, -1.367 and 2.3, for female were 38.6 cm, 0.156 per year, -1.383 and 2.4, for L∞, k and t0, and φ′, respectively.

scholarly journals Monitoring water fluxes in rice plots under three different cultivation methods

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Enrico Antonio Chiaradia ◽  
Daniele Ferrari ◽  
Gian Battista Bischetti ◽  
Arianna Facchi ◽  
Olfa Gharsallah ◽  
...  
Keyword(s):  
Management Practices ◽  
Water Cycle ◽  
Considerable Effect ◽  
Level Gauge ◽  
Total Production ◽  
Water Fluxes ◽  
Wireless Data ◽  
Data Logger ◽  
Groundwater Levels ◽  
The North

Italy is the leading producer of rice in Europe with over half of total production, almost totally concentrated in a large traditional paddy rice area between the Lombardy and Piedmont regions, in the north-western part of the country. In this area irrigation of rice has been traditionally carried out by flooding. The introduction of new combined irrigation and agronomic management practices (dry seeding followed by field flooding and in a full aerobic cultivation with intermittent irrigations), aiming to reduce the water consumption, can determine considerable effect on the landscape and the water cycle. With the aim to study in depth the water fluxes during the whole crop season, three experimental plots at the Ente Nazionale Risi-Rice Research Centre’s Experimental Station of Castello d’Agogna (PV) were instrumented. In each plot the following instruments have been installed: 1) a long throated flume and a double shaped (V-notch and rectangular) thin plate for superficial inputs and outputs, 3) a set of piezometers for groundwater levels, 4) one stage level gauge in each submerged field, 5) four tensiometers and moisture sensors clusters, 6) one eddy covariance station for vapour fluxes estimation. Most of the instruments were equipped with electrical sensors connected by cables to a wireless data logger that, in turn, send the data to a PC placed within ENR offices and web-connected by a LAN. In this way, besides the automatic download of data, it was possible to remotely control the devices, to quickly fix troubles, and to better plan the field trips. The management of the whole framework was done by a specifically developed software. In this paper the whole system, which presents some degree of innovation, is described in detail.

scholarly journals Reducing Substrate Moisture Content during Greenhouse Production of Poinsettia Improves Postproduction Quality and Economic Value

HortScience ◽  
2018 ◽  
Vol 53 (11) ◽  
pp. 1618-1628
Author(s):  
Yanjun Guo ◽  
Terri Starman ◽  
Charles Hall
Keyword(s):  
Moisture Content ◽  
Economic Value ◽  
Growth Index ◽  
Dry Weight ◽  
Leaf Number ◽  
Stem Length ◽  
Total Production ◽  
Greenhouse Production ◽  
Ethylene Concentration ◽  
Substrate Moisture

The objective was to determine the effect of substrate moisture content (SMC) during poinsettia (Euphorbia pulcherrima) greenhouse production on plant quality, postproduction longevity, and economic value. Two experiments were conducted, one in 2016 with ‘Freedom Red’ and the other in 2017 with ‘Christmas Eve Red’. Treatments included two SMC levels (20% or 40%) applied in four timing of application combinations. Total production (TP) time was 14 (2016) or 12 (2017) weeks in which vegetative production (VP) occurred from week 33 (2016) or 35 (2017) to week 39 and reproductive production (RP) continued from week 40 to 47. The four timing of application treatments were 40/40 = TP at 40% SMC; 20/40 = VP at 20% + RP at 40%; 40/20 = VP at 40% + RP at 20%; 20/20 = TP at 20% SMC. After simulated shipping in the dark, plants were evaluated in a simulated retail environment with two packaging treatments: no sleeve covering or plastic perforated plant sleeves covering container and plant. At the end of greenhouse production, plants grown in 20% SMC during RP (20/20 and 40/20) had shorter bract internode length, stem length, and smaller growth index (GI), decreased shoot and root dry weight (DW), and bract and leaf surface area compared with those in 40% SMC during RP (40/40 and 20/40). Photosynthetic rate was higher when plants were watered at 40% SMC regardless of production stage compared with those in 20% SMC. Leaf thickness, petiole thickness, total bract and leaf number were unaffected by SMC treatments. Plants in 20% SMC during RP (20/20 or 40/20) had earlier bract coloring despite days to anthesis being the same for all SMC treatments. Compared with 40/40, 40/20, and 20/20 could save 44.2% or 43.6%, respectively, irrigation and fertilizer usage, and 39.1% and 47.8%, respectively, labor time. During postharvest, ethylene concentration was unaffected by packaging method. Sleeved plants, regardless of SMC treatment, received lower light intensity in the middle of the plant canopy, causing plants to have lower total leaf number due to abscission and SPAD reading at the end of postproduction. The 40/40 treatment abscised more bracts during five weeks (in 2016) of postproduction and with no sleeve had higher number of bracts with bract edge burn (BEB). In summary, reducing SMC to 20% during TP or RP reduced water usage during production and produced more compact plants with increased postproduction quality.

scholarly journals Individual growth of Heleobia piscium in natural populations (Gastropoda: Cochliopidae) from the multiple use natural Reserve Isla Martin Garcia, Buenos Aires, Argentina

2008 ◽  
Vol 68 (3) ◽  
pp. 617-621 ◽  
Author(s):  
SM. Martin
Keyword(s):  
Buenos Aires ◽  
Natural Populations ◽  
Dynamic Structure ◽  
Reproductive Period ◽  
Individual Growth ◽  
Growth Equation ◽  
Multiple Use ◽  
Natural Reserve ◽  
Drainage Channels ◽  
The Individual

The present work analyses the individual growth of Heleobia piscium in natural conditions in coastal drainage channels of the Multiple Use Natural Reserve Isla Martín García, Buenos Aires, Argentina. Isla Martín García is located in the Upper Río de la Plata, to the south of the mouth of the Uruguay river (34° 11' 25" S and 58° 15' 38" W). Monthly collections were made from July 2005 to July 2006 in the eastern part of the island (Arena Beach). The population of H. piscium showed a complex and dynamic structure of sizes during a long period of the annual cycle. Two cohorts could be detected. The Bertalanffy growth equation was: Lt = 6 (1-e -1.85 (t+0.38)) and Lt = 3.9 (1-e -0.19 (t+4.84)) for cohorts 1 and 2, respectively. The pattern of population growth displayed a staggered model, where the greatest growth is observed during the summer. The reproductive period occurred during six months, from the beginning of summer to middle of fall. Based on only one reproductive effort, this pattern is not similar to that of other cogeneric species already studied.

scholarly journals Gas Injection Optimization to Increase Oil Production at MRA PT. PHE ONWJ

2021 ◽  
Vol 2 (2) ◽  
pp. 75
Author(s):  
Harry Budiharjo Sulistyarso ◽  
KRT Nur Suhascaryo ◽  
Mochamad Jalal Abdul Goni
Keyword(s):  
Gas Injection ◽  
Economic Feasibility ◽  
Feasibility Analysis ◽  
Offshore Platforms ◽  
Total Production ◽  
The North ◽  
Artificial Lift ◽  
Production Wells ◽  
Java Sea ◽  
Gas Lift

The MRA platform is one of the offshore platforms located in the north of the Java Sea. The MRA platform has 4 production wells, namely MRA-2ST, MRA-4ST, MRA-5, and MRA-6 wells. The 4 production wells are produced using an artificial lift in the form of a gas lift. The limited gas lift at the MRA Platform at 3.1 MMSCFD makes the production of wells at the MRA Platform not optimal because the wells in the MRA Platform are experiencing insufficient gas lift. Optimization of gas lift injection is obtained by redistribution of gas lift injection for each. The results of the analysis in this study indicate that the optimum gas lift injection for the MRA-2ST well is 0.5552 MMSCFD, the MRA-6 well is 1.0445 MMSCFD, the MRA-5 well is 0.7657 MMSCFD, finally the MRA-4ST well with gas injection. lift is 0.7346 MMSCFD. The manual gas lift in the MRA-4ST is also replaced based on an economic feasibility analysis to ensure that the gas lift injection for each well can be kept constant. The redistribution of gas lift carried out by the author has increased the total production rate of the MRA Platform by 11,160 BO/year or approximately USD 781,200/year. Keywords: Gas lift; Insufficient; Optimization

scholarly journals Somatic growth and age of selected commercial fish species of the Cullera Coast, Iberian Peninsula, south-east Spain

2019 ◽  
Vol 66 (3) ◽  
Author(s):  
Angela Maria Jaramillo-Londono ◽  
Alejandra Vanina Volpedo ◽  
Jose Luis Diaz-Arevalo ◽  
Maria Eugenia Rodrigo-Santamalia ◽  
Vicent Bendito-Dura
Keyword(s):  
Fish Species ◽  
Somatic Growth ◽  
Mesh Size ◽  
Age And Growth ◽  
Biological Information ◽  
Growth Equation ◽  
Commercial Fish ◽  
Mullus Surmuletus ◽  
Von Bertalanffy Growth Equation ◽  
Uranoscopus Scaber

This work provides data on the somatic growth and age of selected commercial fish species of the Cullera Coast, Spain. The biological information available that permits responsible fishing management of these species is relatively scarce. This study was conducted in the Bay of Cullera, Spain (39º 12’to 38º 59’N, and 0º 09’to 0º 15’W); and selected benthic fish species were analysed that are frequently fished by trammel nets (mesh size 28-76 mm) at a maximum depth of 30 m. Maturity , age and growth of 63 torpedoes, Torpedo torpedo (L., 1758), 115 red scorpionfish, Scorpaena scrofa Linnaeus, 1758, 280 red mullets, Mullus surmuletus Linnaeus, 1758, 139 stargazers, Uranoscopus scaber Linnaeus, 1758, and 476 Portuguese soles, Dagetichthys lusitanicus de Brito Capello, 1868 were analysed. The data obtained in this study revealed that 50% of individuals of all the species reached sexual maturity at a TL (total length) of 20.0-36.5 cm and at an age of 2-6 years. The von Bertalanffy growth equation derived were: TL=37.0 (1 - e(-0.2(t + 0.33))); TL =31.5(1 - e(-0.38(t + 0.54))); TL =35.5(1 - e(-0.2(t + 2.08))); and TL =34.3(1 - e(-0.14(t + 2.16))) for S. scrofa, M. surmuletus; U. scaber and D. lusitanicus respectively.

Biomasse et espèces de lichens terrestres disponibles pour le caribou dans le nord du Québec

1990 ◽  
Vol 68 (10) ◽  
pp. 2047-2053 ◽  
Author(s):  
Michel Crête ◽  
Claude Morneau ◽  
René Nault
Keyword(s):  
Plant Cover ◽  
Ground Cover ◽  
Dry Weight ◽  
Common Species ◽  
The West ◽  
The North ◽  
Precipitation Zone ◽  
Annual Consumption ◽  
Mat Thickness ◽  
Primary Unit

Following a two-stage sampling plan, 44 1-km2 primary units were systematically allocated between 53 and 59 ° latitude throughout northern Québec to estimate the biomass of terrestrial lichens. Lichens were collected in two secondary units (0.25 m2) located in parts of each primary unit where lichens were visible from a helicopter (lichen stratum). Overall, the lichen stratum covered 51% of the study area and lichen biomass averaged 1223 kg/ha (dry weight; SE = 201; n = 44). Almost 85% of the variance of this mean was attributable to variability between primary units. The biomass in the west was greater than in the east; it was the highest in the [Formula: see text]700-mm precipitation zone and the lowest in the 500- to 599-mm zone. Data on percent plant cover indicated mat mosses increased in importance over lichens in the east. There was a clear relationship between lichen biomass in secondary units on one hand and mat thickness and percent lichen ground cover on the other. Cladinia stellaris (Opiz) Brodo was the most common species; Alectoria ochroleuca (Hoffm.) Mass. and Cornicularia divergens Ach. were typical of the north, whereas Cladina mitis (Sandst.) Hustich characterized the south of the study area. The annual consumption of lichens by caribou was probably 0.5-0.9% of the available biomass in 1987. Key words: biomass, caribou, Cladina, lichens, Quebec.

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