Optimizing Sampling from Trawl Catches: Contemporaneous Multistage Sampling for Age and Length structures

1992 ◽  
Vol 49 (8) ◽  
pp. 1555-1559 ◽  
Author(s):  
Jukka Horppila ◽  
Heikki Peltonen
Keyword(s):  
Optimal Strategy ◽  
Age Groups ◽  
Sampling Strategy ◽  
Rutilus Rutilus ◽  
Optimal Number ◽  
Optimal Sampling ◽  
Roach Rutilus Rutilus ◽  
Present Scheme ◽  
Multistage Sampling ◽  
Trawl Catches

The objective of this study was to find out the optimal sampling strategy for contemporaneous multistage sampling of age and length structures of trawl catches. Samples were taken from a roach (Rutilus rutilus) stock of Lake Vesijärvi, southern Finland. Two-stage sampling proved to be superior to three-stage sampling (i.e. subsamples from the trawl catches are unnecessary). Assuming that all the age and length groups are equally important, the optimal strategy is to sample 34 fish from each of 46 loads. Compared with the present scheme (500 fish from each of 10 loads), this design cuts down the total variance of the estimated proportions of different age and length groups to about one third. An age–length key was used when estimating the proportions of the age groups. The benefits of the applied age–length key were obvious. The estimates of the proportions of different age groups were more accurate than those obtained with age readings only. Increasing the fraction of age-determined fish increases the costs, diminishes the optimal number of samples, and consequently increases the variance of the estimated proportions of different groups.

Catches, age and growth of the roach Rutilus rutilus (Cyprinidae) in the Middle Ob river basin (within the Tomsk region)

2021 ◽  
pp. 31-40
Author(s):  
Elena Aleksandrovna Interesova ◽  
Alexander Alekseevich Rostovtsev
Keyword(s):  
Positive Relationship ◽  
Age Groups ◽  
Hydrological Regime ◽  
Rutilus Rutilus ◽  
Age And Growth ◽  
Hydroelectric Power Station ◽  
Hydroelectric Power ◽  
Roach Rutilus Rutilus ◽  
Significant Positive Relationship ◽  
Tomsk Region

The data on the catch, age composition and growth of the roach Rutilus rutilus L. in commercial herd in the Middle Ob basin (in the Tomsk region) are presented. It is shown that the catches of the roach in the middle of the 20th century were 2098 tons per year. In the second half of the 1960s, they fell sharply by more than two times. It was caused by a decrease in the areas of effective spawning due to the reduction of runoff in the Ob during spring floods as a result of the regulation of the level regime by the dam of the Novosibirsk hydroelectric power station. After that, the catch of roach remained at about 1013 tons per year until the beginning of economic reforms in the country, when the catch of this species became unprofitable, as a result of which catches decreased to an average of 436 tons per year. Currently, the basis of commercial catches is made up of roach with a commercial length of 140 to 210 mm and a weight of 50 to 150 g at the age of 2+...5+. It is noted, compared with the 1970–1980s, there is a shift in the age series towards an increase in the value of older age groups, which may indicate underutilization of the stock of the roach. The statistically significant positive relationship between catches of roach and the average duration of flooding of the floodplain in the years of the occurrence of generations that form the basis of catches was revealed. Prolonged floods also provide better conditions for fish feeding (a statistically significant positive relationship between the mass of fish of the same age and the duration of flooding of the floodplain is shown). Thus, the hydrological regime in the spring has a decisive influence on the state of the stocks of roach in the Middle Ob.

Optimal sampling of liver parenchyma for electron microscopy

1988 ◽  
Vol 46 ◽  
pp. 334-335
Author(s):  
R. J. Buschmann ◽  
J. W. Ryoo
Keyword(s):  
Analysis Of Variance ◽  
Human Subjects ◽  
Sampling Strategy ◽  
Liver Parenchyma ◽  
Optimal Number ◽  
Optimal Sampling ◽  
Electron Microscopic ◽  
Primary Sample ◽  
Microscopic Studies ◽  
Nested Analysis

We have been studying cirrhosis by morphometric analysis of human and rat liver. Our studies, like most electron microscopic studies, use a tissue sampling scheme that is hierarchical or nested with the number of primary sample units, i.e. the number of human subjects or experimental rats, subsampled by a number of tissue blocks per animal and by a number of micrographs per block. For each study, time and effort is a factorial function of the number of samples at each level. More importantly, the final standard error of the mean is also a function of the number of samples at each level. Thus, optimal sampling is of substantial import.A statistical method, the nested analysis of variance, has been promoted for estimating the optimal number of samples at each level. We have produced a computer program designed to facilitate the use of the nested analysis of variance in determining an efficient sampling strategy.

ANALYSIS OF SOME MORPHOMETRIC AND BIOLOGICAL INDICATORS OF ROACH RUTILUS RUTILUS (LINNAEUS, 1758)

2018 ◽  
pp. 27-34
Author(s):  
Gleb Igorevich Volosnikov ◽  
Elizaveta L'vovna Liberman
Keyword(s):  
Weight Gain ◽  
Age Groups ◽  
Rutilus Rutilus ◽  
Biological Indicators ◽  
Aral Sea ◽  
Compression Method ◽  
Roach Rutilus Rutilus ◽  
Opisthorchis Felineus ◽  
Aral Sea Basin ◽  
The Common

The common roach is a widespread and semi-anadromous fish inhabiting the waters of Europe, Siberia, the Aral Sea basin. Control catches contained roach with a commercial length 12.6-32.6 cm, with a total mass of 41-543 g, age varying within 1+ - 6+. Juvenile stage individuals made - 5.7%, females - 68.6%, males - 25.7%. The annual gain at the age 1+ - 2+ made 3.8 cm, from 2+ to 3+ = 0.6 cm, from 3+ to 4+ = 2.3 cm, from 4+ to 5+ = 2.5 cm, 5+ - 6+ = 2.3 cm. The rate of linear gain decreases from 2+ and equals 3.2%, from 3+ to 4+ = 11.8%, from 4+ to 5+ = 11.5%, from 5+ to 6 + = 9.5%. The annual gain in body weight of species aged from 1+ to 2+ was 50.8 g, from 3+ was 24.8 g, from 4+ = 79.5 g, from 5+ and 6 + = 112.2 and 23.3 g, respectively. From 2+ to 3+ the weight gain is 17.3%, compared to individuals from 1+ to 2+ (85.1%). In the age categories from 3+ to 4+ and 4+ to 5 +, the weight gain was 47.2% and 45.3%, from 5+ to 6+ = 6.5%. In this study, the roach was prevalent in the II and V stages of gonad maturity. Individuals with I and II degrees of fat content were found in all age groups. The study of roach muscles using the compression method revealed the invasion by Opisthorchis felineus (Rivolta, 1884) and Metorchis bilis (Braun, 1790). Invasion extensiveness of O pisthorchis felineus was 28.6%, of Metorchis bilis - 5.7%, combined infestation with two parasites - 2.8%. Invasion activity in opisthorchis was 15.1 specimens, in metorchis - 5.3 specimens, copiousness index made 4.7 and 0.5 copies, respectively.

The linear growth of roach infected with Ligula Intestinalis plerocercoids in the Chivyrkuysky Bay of the lake Baikal

2016 ◽  
Vol 3 (3) ◽  
pp. 312-318
Author(s):  
Дугаров ◽  
Zh. Dugarov ◽  
Ринчинов ◽  
Z. Rinchinov
Keyword(s):  
Body Length ◽  
Lake Baikal ◽  
Linear Growth ◽  
Age Groups ◽  
Rutilus Rutilus ◽  
Time Interval ◽  
Age Classes ◽  
Infection Level ◽  
Roach Rutilus Rutilus ◽  
Ligula Intestinalis

Objective of research: The purpose of the study is to investigate the influence of Ligula intestinalis plerocercoids on linear growth of roach Rutilus rutilus in the Chivyrkuysky bay of the lake Baikal. Materials and methods. Roach was caught on a permanent station in the Monakhovo creek of Chivyrkuysky bay of the lake Baikal at the same time interval (June 25-July 5) in 1997-2005. The analysis of roach infection with L. intestinalis plerocercoids was performed based on incomplete parasitological dissections of 807 host specimens at the age of 0+ to 10+. Standard body length (the distance from the tip of the snout to the anterior end of the caudal fin) was used to characterize the linear growth of roach. Results and discussion. L. intestinalis plerocercoids wasn’t found out in underyearlings (0+) of roach. The host began to be infected with this tapeworm at the age of 1+. The maximum infection level with L. intestinalis plerocercoids was observed in roach at the age of 3+. That one was significantly reduced in the age of 4+. The infection level of roach with L. intestinalis continued to decrease in the next age groups, going down to a minimum at the age of 7+. The roach wasn’t infected with this tapeworm at the age of 8+–10+. A significant reduction of the infection level in the roach in the age classes 4+ and older after the maximum at the age of 3+ was probably associated with parasite-induced mortality of the host during the growth of the age group 3+ to 4+. A standard body length of roach specimens infected with L. intestinalis at the age of 1+ and 2+ was greater than that of uninfected ones. In contrast, the standard body length of the roach specimens infected with this tapeworm was less than that of uninfected ones in subsequent age classes (3 + -6 +). Differences of standard body length between roach specimens infected with L. intestinalis and uninfected ones were statistically significant in the above-mentioned age groups (1 + 6 +). The effect of L. intestinalis plerocercoids on the linear growth of the roach in Chivyrkuysky Bay of the lake Baikal was manifested in an increase of body length of infected host specimens compared to uninfected ones in young age groups (1+ and 2+) and, vice versa, in one’s decrease in age groups 3+–6 +. We proposed to call this effect “reversive”.

Population Characteristics and Feeding of Roach Rutilus rutilus in Small Regulated River of the Kyiv Polissya

2020 ◽  
Vol 56 (1) ◽  
pp. 42-48
Author(s):  
Ye. A. Gupalo ◽  
I. I. Abramyuk ◽  
S. A. Afanasyev ◽  
O. V. Manturova ◽  
Ye. V. Savchenko
Keyword(s):  
Rutilus Rutilus ◽  
Population Characteristics ◽  
Regulated River ◽  
Roach Rutilus Rutilus

scholarly journals Ten-year trends of hypertension treatment and control rate in Korea

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kwang-il Kim ◽  
Eunjeong Ji ◽  
Jung-yeon Choi ◽  
Sun-wook Kim ◽  
Soyeon Ahn ◽  
...  
Keyword(s):  
Age Groups ◽  
Favorable Effect ◽  
Age Group ◽  
Hypertension Treatment ◽  
Treatment Rate ◽  
Cross Sectional ◽  
The Past ◽  
Nationally Representative ◽  
Multistage Sampling ◽  
And Control

AbstractWe analyzed the Korean National Health and Nutrition Examination Survey (KNHANES) database to determine the trends of hypertension treatment and control rate in Korea over the past 10 years. In addition, we tried to investigate the effect of chronic medical conditions on hypertension management. We investigated the hypertension prevalence, awareness, treatment, and control rate from 2008 to 2017. KNHANES, which uses a stratified multistage sampling design, is a cross-sectional, nationally representative survey conducted by the Korean government. A total of 59,282 adults (≥ 20 years) were included, which was representative of the total population of around 40 million Koreans per year. The mean age was 50.7 ± 16.4 years and 42.6% were male. The prevalence of hypertension, hypercholesterolemia, diabetes mellitus, and obesity significantly increased over the 10 years. During this period, the hypertension treatment and control rate significantly improved. Hypertension treatment rate was significantly lower in the younger age group compared to the older age group, but the control rate among the treated patients was not significantly different between age groups. The treatment and control rates of hypertension were higher in patients with multimorbidity, which implies that it has a favorable effect on the treatment and control of hypertension. Hypertension treatment and control rate have improved over the past 10 years. The higher treatment and control rate in patients with multimorbidity suggest that the more aggressive surveillance might be associated with the improvement of hypertension treatment and control rate in Korea.

scholarly journals Investigation into Adaptation in Genes Associated with Response to Estrogenic Pollution in Populations of Roach (Rutilus rutilus) Living in English Rivers

2020 ◽  
Vol 54 (24) ◽  
pp. 15935-15945
Author(s):  
Patrick B. Hamilton ◽  
Anne E. Lockyer ◽  
Tamsyn M. Uren Webster ◽  
David J. Studholme ◽  
Josephine R. Paris ◽  
...  
Keyword(s):  
Rutilus Rutilus ◽  
Roach Rutilus Rutilus
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