scholarly journals A revision of daily egg production estimation methods, with application to Atlanto-Iberian sardine. 2. Spatially and environmentally explicit estimates of egg production

2011 ◽  
Vol 68 (3) ◽  
pp. 528-536 ◽  
Author(s):  
Miguel Bernal ◽  
Yorgos Stratoudakis ◽  
Simon Wood ◽  
Leire Ibaibarriaga ◽  
Luis Valdés ◽  
...  
Keyword(s):  
Temporal Variability ◽  
Environmental Variables ◽  
Egg Production ◽  
Stock Assessment ◽  
Production Model ◽  
Estimation Methods ◽  
Statistical Framework ◽  
Spatio Temporal ◽  
The Relationship ◽  
Made In

Abstract Bernal, M., Stratoudakis, Y., Wood, S., Ibaibarriaga, L., Uriarte, A., Valdés, L., and Borchers, D. 2011. A revision of daily egg production estimation methods, with application to Atlanto-Iberian sardine. 2. Spatially and environmentally explicit estimates of egg production. – ICES Journal of Marine Science, 68: . A spatially and environmentally explicit egg production model is developed to accommodate a number of assumptions about the relationship between egg production and mortality and associated environmental variables. The general model was tested under different assumptions for Atlanto-Iberian sardine. It provides a flexible estimator of egg production, in which a range of assumptions and hypotheses can be tested in a structured manner within a well-defined statistical framework. Application of the model to Atlanto-Iberian sardine increased the precision of the egg production time-series, and allowed improvements to be made in understanding the spatio-temporal variability in egg production, as well as implications for ecology and stock assessment.

scholarly journals Monitoring studies should consider temporal variability to reveal relations between cyanobacterial abundance and environmental variables

2015 ◽  
Vol 87 (3) ◽  
pp. 1717-1726 ◽  
Author(s):  
JULIANA WOJCIECHOWSKI ◽  
ANDRÉ A. PADIAL
Keyword(s):  
Temporal Variability ◽  
Environmental Variables ◽  
Environmental Changes ◽  
Environmental Variability ◽  
Time Lag ◽  
Cyanobacteria Blooms ◽  
Environment Variables ◽  
Sampling Points ◽  
The Relationship

One of the main goals of monitoring cyanobacteria blooms in aquatic environments is to reveal the relationship between cyanobacterial abundance and environmental variables. Studies typically correlate data that were simultaneously sampled. However, samplings occur sparsely over time and may not reveal the short-term responses of cyanobacterial abundance to environmental changes. In this study, we tested the hypothesis that stronger cyanobacteria x environment relationships in monitoring are found when the temporal variability of sampling points is incorporated in the statistical analyses. To this end, we investigated relationships between cyanobacteria and seven environmental variables that were sampled twice yearly for three years across 11 reservoirs, and data from an intensive monitoring in one of these reservoirs. Poor correlations were obtained when correlating data simultaneously sampled. In fact, the 'highly recurrent' role of phosphorus in cyanobacteria blooms is not properly observed in all sampling periods. On the other hand, the strongest correlation values for the total phosphorus x cyanobacteria relationship were observed when we used the variation of sampling points. We have also shown that environment variables better explain cyanobacteria when a time lag is considered. We conclude that, in cyanobacteria monitoring, the best approach to reveal determinants of cyanobacteria blooms is to consider environmental variability.

Spatiotemporal modelling for the annual egg production method of stock assessment using generalized additive models

1998 ◽  
Vol 55 (12) ◽  
pp. 2608-2621 ◽  
Author(s):  
N H Augustin ◽  
D L Borchers ◽  
E D Clarke ◽  
S T Buckland ◽  
M Walsh
Keyword(s):  
Environmental Variables ◽  
Egg Production ◽  
Survey Design ◽  
Stock Assessment ◽  
Generalized Additive Models ◽  
Production Method ◽  
Additive Models ◽  
Atlantic Mackerel ◽  
Egg Density ◽  
Survey Designs

Generalized additive models (GAMs) are used to model the spatiotemporal distribution of egg density as a function of locational and environmental variables. The main aim of using GAMs is to improve precision of egg abundance estimates needed for the annual egg production method. The application of GAMs requires a survey design with good coverage in space and time. If the only results available are from less optimal survey designs, they can be improved by using historical data for spawning boundaries. The method is applied to plankton egg survey data of Atlantic mackerel (Scomber scombrus) in 1995. The GAM-based method improves the precision of estimates substantially and is also useful in explaining complex space-time trends using environmental variables.

An electropalatographic study of Greek spontaneous speech

2001 ◽  
Vol 31 (1) ◽  
pp. 67-85 ◽  
Author(s):  
Katerina Nicolaidis
Keyword(s):  
Temporal Variability ◽  
Spontaneous Speech ◽  
Connected Speech ◽  
Theoretical Frameworks ◽  
Spatio Temporal ◽  
The Relationship ◽  
Production Characteristics

This paper aims to examine spatio-temporal variability during the production of the lingual consonants /t, d, s, z, k, g l, n, XXX/ in a sample of Greek spontaneous speech. It provides a description of the range of segmental variability and explores the relationship between articulatory and temporal variability. It also discusses instances of common connected speech processes including assimilations and deletions. Data from two Greek speakers producing a monologue was recorded with the technique of electropalatography (Reading EPG system). The results indicated that segmental variability ranges over a continuum from over-articulated to under-articulated forms, i.e. fully articulated tokens to very open articulations. In addition, duration dependent variability was found to be a function of the production characteristics of the consonant. Evidence of both gradient and categorical changes in spontaneous speech were suggested by the data and are discussed with reference to current theoretical frameworks.

scholarly journals Relationship Between Spatio-Temporal Leaf Area Index and Crop Coefficient When Monitoring Coffee Plots in Brazil Using the Sentine-2

2019 ◽  
Vol 11 (15) ◽  
pp. 187
Author(s):  
Carolina Jaramillo-Giraldo ◽  
Williams Pinto Marques Ferreira ◽  
Humberto Paiva Fonseca ◽  
Marcelo de Freitas Ribeiro ◽  
Laís Maria Rodrigues Silva ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Temporal Variability ◽  
Crop Coefficient ◽  
Area Index ◽  
Directional Information ◽  
Production Area ◽  
Spatio Temporal ◽  
The Relationship ◽  
Sentinel 2

Robust monitoring techniques for perennial crops have become increasingly possible due to technological advances in the area of Remote Sensing (RS), and the products are available through the European Space Agency (ESA) initiative. RS data provides valuable opportunities for detailed assessments of crop conditions at plot level using high spatial, spectral, and temporal resolution. This study addresses the monitoring of coffee at the plot level using RS, analyzing the relationship between the spatio-temporal variability of the Leaf Area Index (LAI) and the crop coefficient (Kc); the Kc being a biophysical variable that integrates the potential hydrological characteristics of an agroecosystem compared to the reference crop. Daily and one-year Kc were estimated using the relation of crop evapotranspiration and reference. ESA Sentinel-2 images were pre-analyzed and atmospherically corrected, and Top-of-the-Atmosphere (TOA) reflections converted to Top-of-the-Canopy (TOC) reflectance. The TOCs resampled at the 10m resolution, and with the angles corresponding to the directional information at the time of the acquisition, the LAI was estimated using the trained neural network available in the Sentinel Application Platform (SNAP). During 75% of the monitored days, Kc ranged between 1.2 and 1.3 and, the LAI analyzed showed high spatial and temporal variability at the plot level. Based on the relationship between the biophysical variables, the LAI variable can substitute the Kc and be used to monitor the water conditions at the production area as well as analyze spatial variability inside that area. Sentinel-2 products could be more useful in monitoring coffee in the farm production area.

scholarly journals Artisanal fishing characterization and spatio-temporal occurrence of marine shrimp (Crustacea, Decapoda, Penaeidae) in the littoral of Lucena, Paraíba, Brazil

2018 ◽  
Vol 40 ◽  
pp. 47 ◽  
Author(s):  
Glória Cristina Cornélio do Nascimento ◽  
Dimitri De Araújo Costa ◽  
Raquel Ferreira de Sá ◽  
Martin Lindsey Christoffersen ◽  
Maria Cristina Basilio Crispim
Keyword(s):  
Environmental Variables ◽  
Life Cycles ◽  
White Shrimp ◽  
Artisanal Fishing ◽  
Wet Season ◽  
Xiphopenaeus Kroyeri ◽  
Temporal Occurrence ◽  
Spatio Temporal ◽  
Marine Areas ◽  
The Relationship

The present study distinguishes types of fishing activities. It records the most economically exploited shrimps in the municipality of Lucena, Paraíba, Xiphopenaeus kroyeri (“espigudo”), and Penaeus schmitti (white shrimp). From October 2014 to October 2015, samples containing 700 gr of shrimp were collected at three sites of artisanal fishing. Data on temperature, ammonium, nitrate, nitrite, chlorophyll-a, salinity, pH, and dissolved oxygen were recorded.  Two different shrimp species are commercially used in the region, of 2,628 sampled individuals, X. kroyeri predominated, with 1,957 individuals, followed by P. schmitti, with 671 individuals. At localities 1 (in Lucena beach) and 2 (Fagundes beach) both species were present, the X. kroyeri being predominant, but at locality 3 (Costinha beach) only the P. schmitti was recorded. The regional wet season influenced salinity during the months of the year, producing positive or negative correlations among species found at each locality depending on what was analysed. It is relevant to understand the relationship between fishing resources and environmental variables which provide information about fishing dynamics and permits the development of strategies for the maintenance of stocks and fishing areas, as well as permitting the establishment of public regulations for the better preservation and conservation of marine areas and estuaries on which many species depend for the completion of their life cycles. 

The influence of soil moisture conditions on the spatio-temporal variability of event rainfall-runoff coefficients in UK catchments

2021 ◽  
Author(s):  
Yanchen Zheng ◽  
Ross Woods ◽  
Jianzhu Li ◽  
Ping Feng
Keyword(s):  
Soil Moisture ◽  
Temporal Variability ◽  
Estimation Methods ◽  
Runoff Coefficient ◽  
Rainfall Runoff ◽  
Design Flood ◽  
Ungauged Catchments ◽  
Flood Estimation ◽  
Spatio Temporal ◽  
Moisture Conditions

<p>Since the bias and uncertainties of the current design flood estimation methods for ungauged catchments are inevitable, estimation of the design flood in ungauged catchments still remains an unsolved problem. The derived distribution approach appears to be the one of the promising design flood estimation methods, as this method can improve the understanding on which processes contribute most to flood in ungauged catchments. Generally, the distribution of rainfall characteristics and lumped rainfall-runoff modelling was incorporated to estimate the flood magnitude in this method. However, we should note that rainfall is not the only driving factor of flood events. Soil moisture conditions are also an important driving factor affecting the rainfall-runoff transformation, and may even control rainfall-runoff coefficients to a higher degree than does rainfall. Hence, here we perform soil moisture analysis at national scale by employing GLDAS-Noah datasets, and link this to observed event runoff coefficients from a large sample of UK catchments. The relationship between soil moisture conditions and rainfall-runoff coefficient was explored to analyse the spatio-temporal variability of runoff coefficient. This study laid the foundation for further development of a practical derived distribution method, by considering the statistical distribution of rainfall-runoff coefficients and the influence of soil moisture conditions.</p>

Fecundity of the arrow crab Stenorhynchus seticornis in the southern Brazilian coast

2003 ◽  
Vol 83 (5) ◽  
pp. 979-980 ◽  
Author(s):  
Claudia Melissa Okamori ◽  
Valter José Cobo
Keyword(s):  
Temporal Variability ◽  
Environmental Variables ◽  
Environmental Effect ◽  
Egg Production ◽  
Egg Size ◽  
Abiotic Factors ◽  
Scuba Diving ◽  
Average Diameter ◽  
Brazilian Coast ◽  
Rocky Subtidal

The arrow crab Stenorhynchus seticornis (Brachyura, Majidae), is a common inhabitant of the rocky subtidal along the Brazilian coast. Fecundity and the influence of environmental variables on egg production are investigated in this study. Information on egg size and egg loss through incubation are also provided. Monthly samples were conducted using SCUBA diving, from January to December 1998 in the Ubatuba region (23°25′25[double prime or second]S–44°52′03[double prime or second]W), south-eastern Brazilian coast. Early broods were used for the estimation of size-specific relationships of fecundity. Egg loss was assessed by comparing average egg numbers of early and late broods. The fecundity was estimated in 621.1±339.6 eggs, with an average diameter of 0.48±0.1 and 0.57±0.1 mm for early and late eggs, respectively. The number of eggs produced was apparently constant year-round. No significant differences were recorded among monthly fecundity values. The variation of abiotic factors did not show any relationship with temporal variability of fecundity, suggesting that the environmental effect in egg production is slight at best.

Fecundity and Gonado-somatic Index of Trichiurus lepturus (Linnaeus, 1758) Along the Zamboanga del Norte Coast

2018 ◽  
Vol 6 (7) ◽  
pp. 120
Author(s):  
Ma. Dulce C. Guillena
Keyword(s):  
Sex Ratio ◽  
Stock Assessment ◽  
Chi Square ◽  
Moon Phases ◽  
Ovary Weight ◽  
Moment Coefficient ◽  
Trichiurus Lepturus ◽  
Significant Difference ◽  
The Relationship ◽  
Somatic Index

Gonado-somatic index and fecundity are tools for measuring the sexual maturity and ability of animals to reproduce.  This study investigates the reproduction of Trichiurus lepturus. Specifically, this aimed to determine the sex ratio, the GSI, the relationship between fecundity and total length, fecundity and total weight, fecundity and ovary weight. The Descriptive Method of research was used.  Percentage and chi-square was utilized in determining the percentage of occurrence and sex ratio respectively.   Pearson r Product Moment Coefficient of Correlation was used to determine the relationships of the parameters. The study revealed that females outnumbered males and the sex ratio for different month showed significant difference.  Spawning season was observed to occur in November and December as revealed in its GSI values and it synchronized with the full and new moon phases.  Fecundity is positively correlated with body weight, body size, and ovary weight where ovary weight is observed to be the best index for fecundity.  The results of this study could be used further for formal stock assessment of cutlassfish fishery.

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