Assessment of food intensity and growth rate young sevryuga (Acipenser stellatus Pallas, 1771) depending on from the terms of fishing of growing ponds

Author(s):  
Ksenia Andreyevna Akhmedova ◽  
Lidia Mikhailovna Vasilyeva ◽  
Damelya Khazigaleeva Mazanova ◽  
Svetlana Alekseyevna Gutsulyak ◽  
Adelya Zakirovna Anokhina

Artificial reproduction of sturgeon fish in the Volga-Caspian basin in modern conditions is the only real opportunity to replenish natural populations with juveniles, therefore, increasing its efficiency is the key to restoring the stocks of these relict fish species. Improving the technological processes of growing juvenile sturgeon fish, including the Caspian stellate sturgeon, the number of which has been rapidly decreasing in recent years, is one of the main tasks at present. We studied the conditions for growing stellate sturgeon larvae in the nursery ponds for artificial reproduction at different periods of their watering. It is known that the stocking of ponds with larvae that have switched to exogenous feeding occurs at the end of June or the beginning of July, this coincides with the time of maximum water heating in nursery ponds to extreme (26–28 °C) values and with a depletion of the food supply in them. Hydrobiological studies were carried out to assess the food supply in water bodies that were watered in the traditional (June 12–14) terms (control option) and earlier (May 28) 2 weeks earlier than usual (experimental option). In addition, the intensity of feeding and the growth rate of juvenile starred sturgeon in the indicated ponds was studied for 20–24 days. The results of the studies performed showed that the food supply in the experimental pond was higher, so the zooplankton was represented by four orders, the biomass on average ranged from 2,8 to 4,6 g/m³, and in the control variant, planktonic organisms were represented by three orders, total biomass from 0,3 to 2,5 g/m³. The same tendency can be traced for zoobenthos. The feeding intensity of stellate sturgeon fry reared in ponds of early watering had indicators in terms of the gastrointestinal tract filling index, fatness coefficient and growth rates higher than the juveniles kept in water bodies of traditional watering periods.

2021 ◽  
Vol 937 (3) ◽  
pp. 032033
Author(s):  
Elena Shishanova ◽  
Grigory Shishanov ◽  
Dmitry Isaev

Abstract One of the main goals of sturgeon aquaculture is the restoration and renewal of wild populations of sturgeon fish in nature, which creates a tension between selective breeding with maintenance of valuable economic traits in a homozygous state and the need to conserve genetic diversity ensuring fitness in natural environments. It is generally assumed that important economic characteristics, such as body weight and size, growth rate, fecundity, etc., as well as fitness in fish, are associated with heterozygosity and genetic polymorphism of some key metabolic enzymes. It remains unclear whether aquaculture conditions can be as a whole selection factor in favor of certain allelic variants of these enzymes. To establish the relationship between some economic traits and enzymatic polymorphism, we studied the distribution of allelic variants of LDH-3, AAT-2, FGM, and Est enzymes in stellate sturgeon reared in aquaculture. We revealed a frequency bias of some allelic variants of the studied enzymes in a cohort of fish from the generation bred in aquaculture compared to the frequencies of those alleles in wild natural populations. Our study suggests that industrial breeding promotes selection in the direction of reducing size but increasing survival rates, which correlates with certain allelic variants.


2011 ◽  
Vol 26 (S1) ◽  
pp. s96-s97
Author(s):  
T.W. Graham

Liberia's 14 year civil war destroyed domestic agricultural production, veterinary and agricultural education, extension services and domestic food security. These losses severely limited domestic food production, and basic hygiene and sanitation: potable water, abattoirs, cold chain and food storage were greatly diminished. The average Liberian life expectancy fell from 45.8 in 1990 to 41.8 years presently. The population birth and death rate are two of the highest globally with a resulting population growth rate, of 2.7% per annum; this growth rate requires an immediate and concerted focus on domestic food production to alleviate nutritional inadequacy and hunger, trade imbalances and loss of foreign exchange credits. Food supply nationally is presumed adequate because of importation, though domestic production is inadequate. Unequal distribution precludes food security for all Liberians. Value chain augmentation, enhancing food availability across all sectors of Liberian society and ensuring distribution of a safe food supply needs critical development. Infant mortality remains one of the highest in the world (approximately 160/1000 births), much of which is attributed to food insecurity, food contamination and lack of uniformly available potable water. Recreation of Liberia's public health and food security requires redevelopment of disease monitoring and laboratory diagnostic capability to re-establish safe food production and handling practices across all sectors. This will allow determination of endemic disease burden for the principal livestock species: poultry, sheep, goats, cattle and swine. Creation of a national disease surveillance/monitoring system allows for targeted disease intervention, ensuring vaccination for correct serotypes and most critically prevalent diseases. Creation of community level training and support will target intervention of local diseases, but also allow for national prioritization of diseases. Targeting which are most prevalent or most likely to cause production limiting effects will require periodic surveillance, targeted vaccination, and chemotherapeutic intervention and evaluation of therapeutic success.


2003 ◽  
Vol 144 ◽  
pp. s140-s141
Author(s):  
I. Baranowska-Bosiacka ◽  
A. Rzemieniecki ◽  
M. Rutkowska ◽  
G.J. Dietrich ◽  
A. Ciereszko ◽  
...  

2017 ◽  
Vol 30 (1) ◽  
pp. 39-46
Author(s):  
Christian Lane ◽  
Elisa J. Livengood ◽  
Richard D. Miles ◽  
Frank A. Chapman

2021 ◽  
Author(s):  
Omar Lenzi ◽  
Arpat Ozgul ◽  
Roberto Salguero-Gomez ◽  
Maria Paniw

Temporal variation in vital rates (e.g., survival, reproduction) can decrease the long-term mean performance of a population. Species are therefore expected to evolve demographic strategies that counteract the negative effects of vital rate variation on the population growth rate. One key strategy, demographic buffering, is reflected in a low temporal variation in vital rates critical to population dynamics. However, comparative studies in plants have found little evidence for demographic buffering, and little is known about the prevalence of buffering in animal populations. Here, we used vital rate estimates from 31 natural populations of 29 animal species to assess the prevalence of demographic buffering. We modeled the degree of demographic buffering using a standard measure of correlation between the standard deviation of vital rates and the sensitivity of the population growth rate to changes in such vital rates across populations. We also accounted for the effects of life-history traits, i.e., age at first reproduction and spread of reproduction across the life cycle, on these correlation measures. We found no strong or consistent evidence of demographic buffering across the study populations. Instead, key vital rates could vary substantially depending on the specific environmental context populations experience. We suggest that it is time to look beyond concepts of demographic buffering when studying natural populations towards a stronger focus on the environmental context-dependence of vital-rate variation.


Author(s):  
П.Е. Гарлов

С целью повышения эффективности искусственного воспроизводства популяций ценных видов рыб разработаны новые методы управления их размножением, выживаемостью и ростом, которые представлены в виде изобретений. Для управления размножением производителей разработаны методы стимуляции и задержки полового созревания производителей осетровых и костистых рыб. Для стимуляции полового созревания были разработаны препараты изолированной передней и изолированной задней долей гипофиза. Их внедрение в осетроводстве позволило повысить степень их рыбоводного использования в среднем на 15% и достичь экономии гипофиза до 40%. Для задержки полового созревания производителей разработан метод их промышленного резервирования в среде критической солёности 4–8‰, причём как в морской воде, так и в растворах поваренной соли. Производственными испытаниями доказана возможность сохранения рыбоводного качества производителей и получения доброкачественного потомства в этой среде при верхних нерестовых температурах в течение производственно необходимых сроков. С целью заводского воспроизводства природных популяций промысловых рыб разработан метод управления их размножением триадой адекватных экологических факторов ‒ «критической» солёностью, температурой и освещённостью при видоспецифических пороговых воздействиях. На этой основе разработан полносистемный метод воспроизводства популяций ценных видов промысловых рыб (севрюги и Балтийского лосося), охватывающий все этапы заводской биотехники. Новый метод осуществляется путём массовой морской заготовки производителей, получения потомства в морских садках и, после заводского речного выращивания молоди до готовности к миграции, конечного доращивания в морских садках крупной жизнестойкой молоди. Для промышленного внедрения всей предложенной биотехники и круглогодичной аквакультуры разработаны системы водоснабжения рыбоводных заводов и рыбоводных хозяйств на основе внесезонного подземного гидрокондиционирования среды выращивания и на природно-промышленных принципах инженерной экологии. In order to increase the efficiency of artificial reproduction of populations of valuable fish species new methods for managing their reproduction, survival and growth have been developed, which are presented in the form of inventions. To control the reproduction of producers methods have been developed to stimulate and delay puberty of sturgeon and bony fish producers. To stimulate puberty preparations for the isolated anterior and isolated posterior lobes of the pituitary gland have been developed. Their introduction in sturgeon breeding made it possible to increase the degree of their fish farming use by an average of 15% and to achieve a pituitary gland economy of up to 40%. To delay the puberty of producers, a method for their industrial reservation in an environment of critical salinity of 4–8‰ has been developed both in sea water and in solutions of sodium chloride. Production tests have proven the possibility of preserving the fish-breeding quality of producers and obtaining benign offspring in this environment at the upper spawning temperatures during the production required periods of time. With the aim of factory reproduction of natural populations of commercial fish a method has been developed to control their reproduction by a triad of adequate ecological factors – “critical” salinity, temperature and illumination under species-specific threshold effects. On this basis a full-system method of reproducing populations of valuable species of commercial fish (stellate sturgeon and Baltic salmon) has been developed covering all stages of factory biotechnology. The new method is carried out by mass marine harvesting of producers obtaining offspring in sea pens and after the factory river rearing of hatchling until ready for migration the final rearing of large viable juveniles in sea pens. For the industrial introduction of all the proposed biotechnics and year-round aquaculture, water supply systems for fish breeding plants and fish farms were developed on the basis of off-season underground hydroconditioning of the growing environment and on the natural and industrial principles of engineering ecology.


2018 ◽  
Vol 19 (3) ◽  
pp. 269-284
Author(s):  
V.R. Krokhalevskiy ◽  
◽  
I.B. Babkina ◽  
A.M. Vizer ◽  
M.A. Dorogin ◽  
...  

Oryx ◽  
2013 ◽  
Vol 47 (2) ◽  
pp. 266-272 ◽  
Author(s):  
Mahmoud-Reza Hemami ◽  
Moslem Momeni

AbstractHistorically, the onager or Persian wild ass Equus hemionus onager, endemic to Iran, was widespread on the arid and semi-arid central steppes but only two natural populations remain. We estimated the population density of the onager in Qatruiyeh National Park using line transect distance sampling. Transects were surveyed on three plains in the Park and the results compared with total counts conducted by the Department of Environment. Our estimate (109 onagers per 100 km2; 95% confidence interval 67–179) is similar to that obtained by the total counts (137 onagers per 100 km2). Distance sampling is therefore a promising method for estimating the abundance of the onager. Using the annual censuses performed by the Department of Environment over the last 13 years we estimated that the population has a growth rate of 0.09. During the same period the onager population in the Touran Protected Complex has experienced a severe decline. The high density of onagers within the National Park indicates the unsuitability of adjacent habitats, including Bahram-e-Goor Protected Area, for this species. Lack of sufficient security and poorly distributed water sources appear to be the main reasons discouraging onagers from entering the Bahram-e-Goor Protected Area. We recommend and describe management interventions that could potentially assist in maintaining the last surviving onager populations in Iran.


Fisheries ◽  
2021 ◽  
Vol 2021 (4) ◽  
pp. 68-75
Author(s):  
Eduard Vladimirovich Bubunets ◽  
Alexander Vladislavovich Labenets ◽  
Alexey Vasilevich Zhigin

The temperature conditions and the results of wintering of producers, incubation of caviar of sevryuga and thorn in farms on waste warm waters are considered. The studied indicators are compared with similar data obtained when keeping producers from natural populations in the lower reaches of the Volga River. In the considered species, with a shortened and comfortable "warm" wintering (for sevryuga at 5-11, thorn – 3-15°C), an increase in the duration of incubation up to a day or more was recorded in comparison with individuals from natural populations. The temperature regulations of wintering for producers, incubation and maintenance of free embryos are proposed.


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