scholarly journals Age, growth, and reproductive season of bluefish (Pomatomus saltatrix) in the Marmara region, Turkey

2007 ◽  
Vol 64 (3) ◽  
pp. 531-536 ◽  
Author(s):  
Tevfik Ceyhan ◽  
Okan Akyol ◽  
Adnan Ayaz ◽  
Francis Juanes
Keyword(s):  
Return Migration ◽  
Growth Parameters ◽  
Age Groups ◽  
Early Spring ◽  
Reproductive Period ◽  
Reproductive Season ◽  
The Black Sea ◽  
Marmara Region ◽  
Pomatomus Saltatrix ◽  
L 51

AbstractCeyhan, T., Akyol, O., Ayaz, A., and Juanes, F. 2007. Age, growth, and reproductive season of bluefish (Pomatomus saltatrix) in the Marmara region, Turkey. – ICES Journal of Marine Science, 64: 531–536. Bluefish (Pomatomus saltatrix) are distributed widely along the Turkish coasts, and are regularly captured, especially in the Sea of Marmara during their spawning migration to the Black Sea from the Mediterranean in spring and during their return migration south in early autumn. Age, growth, and reproductive season are reported. The ages of 1114 bluefish were determined from otoliths. The age groups ranged from 0 to III, and mean fork lengths (and weights) were 14.4 ± 0.12 cm (38.2 ± 1.02 g), 19.5 ± 0.06 cm (93.7 ± 0.86 g), 27.5 ± 0.48 cm (238.5 ± 11.3 g), and 33.3 ± 0.50 cm (431.9 ± 17.08 g) for each age group, respectively. The von Bertalanffy growth parameters were L∞ = 51 cm, K = 0.228, and t0 = −1.26 y. The reproductive period, evaluated from gonadosomatic indices, began in early spring and extended until August.

scholarly journals Some biological properties of spiny eel (Mastacembelus mastacembelus, Banks & Solander, 1794) living in the Upper Euphrates River Basin, Turkey

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mehmet Zülfü Çoban ◽  
Mücahit Eroğlu ◽  
Mustafa Düşükcan
Keyword(s):  
River Basin ◽  
Growth Parameters ◽  
Age Groups ◽  
Mortality Rates ◽  
Biological Properties ◽  
Von Bertalanffy ◽  
Growth Type ◽  
Euphrates River ◽  
Fish Samples ◽  
Exploitation Rate

AbstractThis study was carried out to determine some bioecological characteristics of Mastacembelus mastacembelus, which is the only species of Mastacembelidae family living in Turkey. Fish samples were caught between 2014–2018 from Keban Dam Lake, one of the most important reservoirs of the upper Euphrates Basin. In totally, 348 Mastacembelus mastacembelus individuals were examined, including 178 males and 170 females. The age distributions were defined between the I–XV age groups. Total lengths ranged from 14.20 to 81.80 cm in males and from 15.60 to 77.30 cm in females. Total length–weight relationships were calculated as W = 0.0083 × TL2.6516 for males, W = 0.0043 × TL2.8310 for females and W = 0.0063 × TL2.7256 for all population, and the growth type was estimated as “negative allometric”. The von Bertalanffy growth parameters for all individuals were computed as L∞ = 90.99, k = 0.13, t0 = − 0.45. The total (Z), natural (M), fishing (F) mortality rates and exploitation rate (E) were estimated as Z = 0.313, M = 0.270, F = 0.043 and E = 0.137, respectively. The length at first capture (Lc) was found as 50.72. The optimum, maximum and economic yields were calculated as E0.5 = 0.361; Emax = 0.776; E0.1 = 0.664, respectively.

scholarly journals The Role of Family and Friends in Return Migration and Its Labor Market Outcomes

2021 ◽  
Author(s):  
Brian Joseph Gillespie ◽  
Clara H. Mulder ◽  
Christiane von Reichert
Keyword(s):  
Labor Market ◽  
Survey Data ◽  
Significant Relationship ◽  
Return Migration ◽  
Labor Market Outcomes ◽  
Age Groups ◽  
Market Outcomes ◽  
Market Stability ◽  
Onward Migration

AbstractDrawing on survey data on individuals’ motives for migration in Sweden (N = 2172), we examine the importance of family and friends for return versus onward migration, including their importance for different age groups and in different communities on the rural–urban spectrum. The results point to a significant relationship between the importance of family and return versus onward migration, with family importance decreasing with age among returning migrants. At the same time, the importance of friends for returning increases with age. The findings did not suggest a significant relationship between urbanicity and returning versus migration elsewhere. Based on a subset of respondents who were employed prior to migrating (n = 1056), we further examined labor market outcomes for onward versus returning migrants. The results broadly indicate that return migrations are linked to lower likelihoods of labor market deterioration and improvement, suggesting greater labor market stability for return vis-à-vis onward migrations. However, the importance of family for returning (versus moving elsewhere) is associated with higher likelihoods of labor market deterioration and improvement compared with staying the same, indicating greater volatility in labor market outcomes when the importance of family is considered.

scholarly journals Human Sapovirus among Outpatients with Acute Gastroenteritis in Spain: A One-Year Study

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 144 ◽  
Author(s):  
Miguel F Varela ◽  
Enrique Rivadulla ◽  
Alberto Lema ◽  
Jesús L Romalde
Keyword(s):  
Acute Gastroenteritis ◽  
Age Groups ◽  
The Elderly ◽  
Mean Value ◽  
Early Spring ◽  
Clinical Samples ◽  
Late Winter ◽  
Viral Pathogen ◽  
One Year ◽  
Different Strains

Viral agents of human gastroenteritis affect people of all ages across the globe. As a mainly self-limiting disease, it is difficult to evaluate the real prevalence of etiological agents circulating in each region. Many of the analyzed outbreaks are caused by viruses of the family Caliciviridae, especially the genus Norovirus (NoV). Most studies have focused on other enteric viruses, leaving sapovirus (SaV) underestimated as an important emerging human threat. This one-year study analyzed clinical samples from hospital outpatients with acute gastroenteritis in Spain, with the aim of revealing the importance of human SaV as an emerging viral pathogen. A total of 2667 stools were tested using reverse transcription (RT)-qPCR to detect and quantify SaV. Sapovirus was detected in all age groups, especially in infants, children, and the elderly. The prevalence was 15.64% (417/2667), and was slightly higher in 0–2- and 3–5-year-olds (19.53% and 17.95%, respectively) and much lower in 13–18-year-olds (9.86%). Positive samples were detected throughout the year, with peaks of detection during autumn and the late winter to early spring months. The mean value for the quantified samples was 6.5 × 105 genome copies per gram of stool (GC/g) (range 2.4 × 103–6.6 × 1011 GC/g). RT-nested PCR and sequencing were used for further genotyping. Genetic characterization showed a predominance of genogroup I (GI), followed by GII and GIV. The detection of multiple genotypes suggests the circulation of different strains without any clear tendency. The results obtained suggest SaV as the second major gastroenteritis agent after NoV in the region.

A Paleomagnetic Study of the Tectonic Deformation in Circum-Marmara Region, NW Anatolia, during the Late Cretaceous and Cenozoic Period

2020 ◽  
Author(s):  
Burak Semih Cabuk ◽  
Mualla Cengiz
Keyword(s):  
Upper Cretaceous ◽  
Rock Magnetism ◽  
Volcanic Rocks ◽  
High Coercivity ◽  
The Black Sea ◽  
Tectonic Deformation ◽  
Marmara Region ◽  
Magnetic Minerals ◽  
Single Plate ◽  
Paleomagnetic Study

<p>The Marmara region is located on the Alpine Himalayan orogenic belt which experienced a active tectonic deformation. The region consists of tectonic units such as the Istanbul Zone, the Strandja Zone and the Sakarya Continent. It is reported in the previous geological studies that the Istanbul Zone began to move southwards appart from the Moesia Platform with the effect of West Blacksea Fault in the west and West Crimea Fault in the east after the the opening of the Black Sea in the Cretaceous. It is known that the Intra Pontide suture is formed after the closure of the Intra-Pontide ocean during the Early Eocene due to the collision between İstanbulzone and the Sakarya continent which moved northwards. As a result of the continental collision, the region has completed its evolution under the influence of basin formation and the emplacement of North Anatolian Fault Zone from Miocene to the present.</p><p> </p><p>In this study, Upper Cretaceous-Oligocene sedimentary and volcanic rocks were sampled at 103 sites to investigate the tectonic deformation of the area. As a result of rock magnetism studies, it was shown that magnetic minerals in sedimentary and volcanic rocks are defined by titanium-rich titanomagnetite showing low coercivity, while in limestone samples, magnetization is defined by hematite showing high coercivity. As a result of anisotropy of magnetic susceptibility (AMS) measurements, it was observed that most of the samples show magnetic foliation and a deformation ellipsoid which is oblate. Paleomagnetic results show counterclockwise rotation of 19.9°±10.9° for the Sakarya continent, 27.4°±11.6°for the Pontides and 15.6°±11.8°for the Strandja Zone from Eocene to present. The results indicate that the region has completed the collision in Eocene and rotated counterclockwise as a large block. Deformation due to basin development or fault bounded block rotations which developed after Miocene could not been detected in this study. Miocene paleomagnetic data from previous studies in the study area are compatible with counterclockwise rotations in Upper Cretaceous-Oligocene which shows that different blocks emplaced in the study area moved together as a single plate during Eocene-Miocene time.</p>

Evaluation of Different eCG Doses + Progesterone to Induce Reproductive Activity During the Transitional Reproductive Season in Anestrous Creole Goats

2020 ◽  
Author(s):  
F. G. Véliz-Deras ◽  
S. Zúñiga-García ◽  
G. Calderón-Leyva ◽  
J. Otal-Salaverri ◽  
S. Moreno-Avalos ◽  
...  
Keyword(s):  
Chorionic Gonadotropin ◽  
Reproductive Behavior ◽  
Reproductive Activity ◽  
Reproductive Period ◽  
Reproductive Season ◽  
Reproductive Seasonality ◽  
Experimental Protocols ◽  
Equine Chorionic Gonadotropin ◽  
Experimental Treatments ◽  
Different Doses

Background: Goats from subtropical and temperate latitudes show reproductive seasonality. For this reason, the products obtained from goats also shows the same seasonality, reducing the finances of goat keepers. Several studies have focused on reducing reproductive seasonality through the use of hormonal protocols based on progestogens, in addition to the use of equine chorionic gonadotropin (eCG) hormone, used for its double biological activity that ensures an optimal response to induce estrus and pregnancy in goats. The objective was to assess whether reduced doses of eCG are effective in inducing reproductive activity in anestrous goats. Methods: During the transition reproductive period (June), mix-breed Creole goats (n=39), were treated with intramuscular progesterone (P4), later, the experimental treatments, consisting in different doses (50, 100, 50+50 or 200 IU) of equine chorionic gonadotropin (eCG) were applied. After the application of the experimental protocols, the reproductive activity of the goats was evaluated. Result: This study shows that one dose of 100 IU of eCG effectively induced reproductive behavior in anestrous Creole goats towards the end of the seasonal anestrus. This protocol makes the use of exogenous hormones more efficient, with reduce doses, decreasing expenses and is practical use by goat producers.

Spread, Growth Parameters, and Reproductive Potential for Brown Flatsedge (Cyperus fuscus)

2010 ◽  
Vol 3 (3) ◽  
pp. 240-245 ◽  
Author(s):  
Charles T. Bryson ◽  
Richard Carter
Keyword(s):  
Growth Parameters ◽  
Indian Subcontinent ◽  
Reproductive Potential ◽  
Early Spring ◽  
Effective Control ◽  
Pearl River ◽  
Control Methods ◽  
Rice Agriculture ◽  
Greenhouse Experiments ◽  
Ecological Range

AbstractBrown flatsedge (Cyperus fuscus) is widely distributed in Europe, Asia, the Indian subcontinent, and the Mediterranean region of Northern Africa. It was apparently introduced into North America in the late 1800s and has steadily moved southward and westward. Brown flatsedge is reported new to Arkansas and Mississippi herewith. Field observations from early spring until frost were made between 2003 and 2007 from populations present at three sites: Chicot County, Arkansas, and Pearl River and Washington counties, Mississippi. Under natural field conditions, brown flatsedge plants germinated from late March and early April until frost. Inflorescences were observed in mid-May and seed production continued until frost. In field populations, the average numbers of scales per spikelet, inflorescences per plant, and spikelets per inflorescence were 15, 28, and 33, respectively. Greenhouse experiments were established in 2008 at Stoneville, MS, to determine growth parameters and the reproductive potential of brown flatsedge. In greenhouse experiments, by 10 wk after emergence (WAE), brown flatsedge plants were 30.2 cm tall and 63.9 cm in diameter, and dry weights were 1.4, 1.0, 2.0, 0.5, and 1.9 g for roots, culms, leaves, bracts, and inflorescences, respectively. Brown flatsedge culms and inflorescences appeared 5 WAE, and by 9 WAE all plants were producing seed. Brown flatsedge could pose a threat to natural plant communities and rice agriculture in Arkansas, Louisiana, Mississippi, Missouri, Tennessee, and Texas. Additional research is needed to determine seed longevity and ecological range potential, and to develop inexpensive and effective control methods.

Field and laboratory studies on the life-cycle, growth and feeding preference in the hairy snail Trochulus hispidus (L., 1758) (Gastropoda: Pulmonata: Hygromiidae)

Biologia ◽  
2013 ◽  
Vol 68 (1) ◽  
Author(s):  
Małgorzata Proćków ◽  
Magda Drvotová ◽  
Lucie Juřičková ◽  
Elżbieta Kuźnik-Kowalska
Keyword(s):  
Life Cycle ◽  
Food Preferences ◽  
Land Snail ◽  
Feeding Preference ◽  
Early Spring ◽  
Reproductive Period ◽  
Acer Pseudoplatanus ◽  
Annual Life Cycle ◽  
Cycle Growth ◽  
In The Wild

AbstractFor the first time the life cycle of the common land snail Trochulus hispidus was completely described in Central Europe (Poland). This is a semelparous species predominantly with an annual life cycle and the reproductive period lasting from April till October. The first young snails hatch in spring, grow rapidly in summer and reach ca. 4 whorls until winter. In spring of the next year they mature and reproduce. After that they die. There is hardly any growth from late autumn till early spring. The average proportional growth rate is ca. 0.3 whorl/month in the wild. The fastest growth is present in the youngest snails and then gradually decreases over the course of their age. Laboratory and field observations allowed for establishing the following life cycle parameters: eggs calcified, almost spherical, ca. 1.5 mm, laid in spring and summer in batches of between 1 and 47. Time to hatching is 6–24 days, hatching is asynchronous; newly-hatched snails have approximately 1.5 whorls. Analysis of food preferences revealed, that T. hispidus tends to restrict its diet during the life. Generally the youngest snails equally consumed leaves of all four tree species offered (Fraxinus excelsior, Acer pseudoplatanus, Tilia cordata and A. platanoides) whereas adults preferred F. excelsior over A. pseudoplatanus and A. platanoides.

scholarly journals Properties of age compositions and mortality estimates derived from cohort slicing of length data

2014 ◽  
Vol 72 (1) ◽  
pp. 44-53 ◽  
Author(s):  
Lisa E. Ailloud ◽  
Matthew W. Smith ◽  
Amy Y. Then ◽  
Kristen L. Omori ◽  
Gina M. Ralph ◽  
...  
Keyword(s):  
Growth Parameters ◽  
Age Groups ◽  
Total Mortality ◽  
Frequency Distributions ◽  
Accuracy And Precision ◽  
High K ◽  
Length Data ◽  
High Age ◽  
Low K ◽  
Mortality Estimates

Abstract Cohort slicing can be used to obtain catch-at-age data from length frequency distributions when directly measured age data are unavailable. The procedure systematically underestimates the relative abundance of the youngest age groups and overestimates abundance at older ages. Cohort-sliced catch-at-age data can be used to estimate total mortality rate (Z) using a regression estimator or the Chapman–Robson estimator for right truncated data. However, the effect of cohort slicing on accuracy and precision of resulting Z estimates remains to be determined. We used Monte Carlo simulation to estimate the per cent bias and per cent root mean square error of the unweighted regression, weighted regression, and Chapman–Robson mortality estimators applied to cohort-sliced data. Incompletely recruited age groups were truncated from the cohort-sliced catch-at-age data using previously established recommendations and a variety of plus groups was used to combine older age groups. The sensitivity of the results to a range of plausible biological combinations of Z, growth parameters, recruitment variability, and length-at-age error was tested. Our simulation shows that cohort slicing can work well in some cases and poorly in others. Overall, plus group selection was more important in high K scenarios than it was in low K scenarios. Surprisingly, defining the plus group to start at a high age worked well in some cases, although length and age are poorly correlated for old ages. No one estimator was uniformly superior; we therefore provide recommendations concerning the appropriate estimator and plus group to use, depending on the parameters characterizing the stock. We further recommend that simulations be performed to determine exactly which plus group would be most appropriate given the scenario at hand.

scholarly journals Age, growth and mortality of the European Seabass, (Dicentrarchus Labrax) in Bardawil lagoon, North Sinai, Egypt

2021 ◽  
pp. 042-046
Author(s):  
El-Desoki Menna O ◽  
Younis Younis M ◽  
A Youssef El-Dakar ◽  
Ahmed Salem M ◽  
Ahmed Kassem S ◽  
...  
Keyword(s):  
Growth Parameters ◽  
Age Groups ◽  
Dicentrarchus Labrax ◽  
Mortality Rates ◽  
Von Bertalanffy ◽  
Fishing Mortality ◽  
European Seabass ◽  
Exploitation Rate ◽  
The Relationship ◽  
North Sinai

Age, growth, and mortality of European Seabass (Dicentrarchus labrax) were studied from a small-scaled fishery of Bardawil lagoon, (North Sinai, Egypt). 181 specimens (16.6 to 35 cm total Length and 39.8 to 367.2 g total weight). The relationship between length and weight was W = 0.0054L3.1428. Age was determined by otoliths and age groups I to IV years were observed. Growths in length and weight at the end of each year were calculated. The growth parameters of von Bertalanffy equation were calculated as (L∞ = 48.69 cm, K = 0.1677 yr -1 and t0 = -0.447 yr -1). Growth performance index was calculated (φ = 2.60 for length and 1.25 for weight). Mortality rates were 0.867 yr-1, 0.25 yr1and 0.617 yr-1 for total, natural and fishing mortality, respectively. The currently exploitation rate E = 0.712 yr-1 indicating that, the population of this species is being heavily exploited.

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