CRITICAL FACTORS OF WATER CONTENT FOR FISH STOCKS IN THE WATER RESERVOIRS OF KAZAKHSTAN

2017 ◽  
pp. 9-18
Author(s):  
Saule Zhangirovna Asylbekova ◽  
Kuanysh Baibulatovich Isbekov ◽  
Evgeniy Vyacheslavovich Kulikov
Keyword(s):  
Water Content ◽  
Water Level ◽  
Water Availability ◽  
Hydrological Regime ◽  
Fishing Effort ◽  
Water Reservoirs ◽  
The Caspian Sea ◽  
Annual Fish ◽  
Commercial Fish ◽  
Fish Stocks

The hydrological regime of water reservoirs in different years has a decisive impact on the abundance of commercial fish stocks and the quality of ichthyocenoses. In this connection in 2015-2016 there was conducted a retrospective analysis and ranking of hydrological regime impact on these factors. The paper gives evaluation of catches and fish stocks under different scenarios of water availability in the main fishing ponds of the Republic of Kazakhstan that give about 80% of the annual fish catch of the country (except the Caspian Sea). There were analyzed 2000 factors of hydrological regime (water level, annual discharge) and 1845 factors of fishing stocks (catches, abundance, fish biomass). The paper determines the critical characteristics of water availability for fish stocks. There have been proposed a number of administrative decisions and actions in case if water content would approach to the critical level. Among them: limitation of fish catches in the following year; widening zones restricted for fishing; intensification of safety measures of the fish young in residual ponds during arid periods; introduction of catch standards for a unit of fishing effort in low-water years, high-water years and years with normal water level in rivers.

Dependence of efficiency of natural fish reproduction in water bodies of Kazakhstan from water level

2021 ◽  
pp. 32-41
Author(s):  
K.B. Isbekov ◽  
E.V. Kulikov ◽  
S.Zh. Asylbekova
Keyword(s):  
Water Content ◽  
Water Regime ◽  
Juvenile Fish ◽  
Hydrological Regime ◽  
Water Bodies ◽  
Fish Reproduction ◽  
Data Set ◽  
Commercial Fish ◽  
Level Of Significance ◽  
The Impact

The article deals with the relationship between the hydrological regime of water bodies and the efficiency of fish reproduction. The hydrological regime of water bodies in years of different water content influences the reproduction and, accordingly, the quantitative and qualitative composition of ichthyocenoses. The easiest way to assess the efficiency of fish reproduction is by such an indicator as the productivity of juveniles, i.e. the number of juvenile fish per unit area or volume. The material for this work was carried out in large fishing reservoirs of the Republic of Kazakhstan in the process of fishery research (2013–2018). Comparison of hydrological parameters and productivity of juveniles by years shows their relationship. Correlation coefficient between water content (runoff) of the river Zhaiyk and juvenile yield +0.73 (data set for 11 years, reliable for the level of significance p = 0.01). The yield of juvenile fish from Lake Balkhash has a high correlative dependence on the inflow of water into the lake (r = +0.826) (massif 2013–2018, reliable for the level of significance p = 0.05). Correlation analysis showed that the productivity of juvenile fish in the Kapshagai reservoir has an average degree of dependence on water content (average annual level) (r = +0.641, reliable for the level of significance p = 0.05). Regular relationships between the water regime and the efficiency of reproduction (productivity of juveniles) of fish have been established. The efficiency of natural reproduction of commercial fish species in modern conditions of the water regime, water withdrawal for economic needs and the impact of fishing is significantly reduced, but with the implementation of the reclamation measures proposed in the work, its partial restoration is possible.

scholarly journals North Sea cod recovery?

2006 ◽  
Vol 63 (6) ◽  
pp. 961-968 ◽  
Author(s):  
Joe Horwood ◽  
Carl O'Brien ◽  
Chris Darby
Keyword(s):  
North Sea ◽  
Gadus Morhua ◽  
Mortality Rates ◽  
Fishing Effort ◽  
Current Status ◽  
Fishing Mortality ◽  
Commercial Fish ◽  
Fish Stocks ◽  
Stock Assessments ◽  
Low Levels

AbstractRecovery of depleted marine, demersal, commercial fish stocks has proved elusive worldwide. As yet, just a few shared or highly migratory stocks have been restored. Here we review the current status of the depleted North Sea cod (Gadus morhua), the scientific advice to managers, and the recovery measures in place. Monitoring the progress of North Sea cod recovery is now hampered by considerable uncertainties in stock assessments associated with low stock size, variable survey indices, and inaccurate catch data. In addition, questions arise as to whether recovery targets are achievable in a changing natural environment. We show that current targets are achievable with fishing mortality rates that are compatible with international agreements even if recruitment levels remain at the current low levels. Furthermore, recent collations of data on international fishing effort have allowed estimation of the cuts in fishing mortality achieved by restrictions on North Sea effort. By the beginning of 2005, these restrictions are estimated to have reduced fishing mortality rates by about 37%. This is insufficient to ensure recovery of North Sea cod within the next decade.

scholarly journals ON THE QUESTION OF FISHERY REGIME REGULATION IN THE VOLGA-CASPIAN BASSIN (ASTRAKHAN REGION) BY THE EXAMPLE OF NORTH-CASPIAN ROACH

2018 ◽  
pp. 41-48
Author(s):  
Vitaliy Victorovich Barabanov ◽  
Sergey Yurievich Nikiforov
Keyword(s):  
Hydrological Regime ◽  
Fishing Effort ◽  
Major Purpose ◽  
Spawning Grounds ◽  
Commercial Fish ◽  
Factors Affecting ◽  
Fish Catch ◽  
And Gender ◽  
Negative Factors ◽  
Caspian Roach

The article shows the assessment of fishing conditions of roach catches (the number of fishing grounds, fishing gears, catches, catches per unit of fishing effort, fishing intensity, etc.) at the main fishery objects of the Volga delta. There has been made the analysis of structure of size and gender composition of roach from commercial and amateur catches. The results have shown a depression of the population with negative dynamics in future. There have been determined main negative factors affecting the state of roach stock: unfavorable hydrological regime, incoordination in terms of commercial and amateur catches, limits of catch and size. In such circumstances the major purpose is to create a fishing regime, when maximum pass of fish spawners to spawning grounds is provided. The article proposes organizing a special regime of fishing roach with the aim to introduce additional limitations to the commercial fish catch, the main point of which is a transition from fine-meshed seines to medium-meshed seines in the day, when the water level in the Astrakhan region achieves an index mark as 350 cm. This measure will allow assuring a maximum pass of roach spawners to spawning grounds. A similar interdiction must be valid for amateur fishing. It should be noted that this interdiction is a provisional measure allowing to preserve and reproduce roach population.

THE NUMBER AND QUALITATIVE CHARACTERISTICS OF FRY FISH IN SHALLOW COASTAL WATERS OF THE VOLGA IN THE SUMMER-AUTUMN PERIOD OF 2012

2017 ◽  
pp. 65-73
Author(s):  
Edward Vladimirovich Nikitin
Keyword(s):  
Fish Species ◽  
Coastal Waters ◽  
Caspian Sea ◽  
The Caspian Sea ◽  
Volga River ◽  
Commercial Fish ◽  
Autumn Period ◽  
Fish Juveniles ◽  
Qualitative Characteristics ◽  
Shallow Coastal Waters

Shallow coastal waters of the Volga river is a flooded feeding area for fish juveniles of nonmigratory fish species. There takes place annual downstream migration of fluvial anadromous fish species from spawning grounds of the Volga river to the Northern Caspian Sea. The most important factors determining the number and qualitative characteristics of fry fishes are the level of the Caspian Sea (currently having a tendency to the lowering), hydrological and thermal regimes of the Volga river. Researches were carried out in definite periods of time. In the summer-autumn period of 2012 fry fishes were presented by 19 species (13 of them were commercial species), which belonged to 9 families. The article gives data on all the commercial fish species. In the first decade of July the maximum number of fry fish was registered in the western part of the Volga outfall offshore - in box 247 (19.86 mln specimens/km2), in the eastern part - in box 142 (20.4 mln specimens/km2). The most populous were roach, red-eye, silver bream and bream; size-weight characteristics were better in the areas remoted from the Volga delta. In the third decade of July the quantitative indicators of fry fish on these areas decreased, size-weight characteristics greatly increased. In the second decade of October in the western part of the seaside there were registered increased pre-wintering concentrations of fish juveniles, their qualitative indicators increased, which is evidence to favorable feeding conditions in 2012.

HYDROLOGICAL REGIME AND FREEZING OF HUMMOCKY BOGS ON THE EUROPEAN NORTH OF RUSSIA

2019 ◽  
Vol 12 (9-10) ◽  
pp. 38-48
Author(s):  
V. I. Batuev ◽  
I. L. Kalyuzhny
Keyword(s):  
Water Level ◽  
Hydrological Regime ◽  
Average Intensity ◽  
Water Level Rise ◽  
Northern European ◽  
European North ◽  
Bog Waters ◽  
Northern European Russia ◽  
Seasonal Thawing ◽  
First Time

The development of the European North of Russia, where flat and high-hummocky bog complexes are spread, requires information on the processes of formation of their hydrological regime and freezing of this territory. For the first time, based on observational data, for the period from 1993 to 2013, characteristics of the hydrological regime and freezing of hummocky bogs in Northern European Russia are presented, the case study of the Lovozerskoye bog. The observations were carried out in accordance with the unified methods, approved for the specialized network of Roshydromet bog stations. The regularities of the formation of the hydrological regime of hummocky bogs have been revealed: bog water level drops dramatically from the beginning of freezing to the end of March, rises during snow melt period, slightly drops in summer and rises in autumn. The main feature of hummocky bogs is permafrost, which determines their specific structure. It has been discovered that gravitation snowmelt and liquid precipitation waters relatively quickly run down the hummocks over the frozen layer into hollows between them. Levels of bog waters on the hummocks are absent for a longer period of time. In spring, the amplitude of water level rise in swamplands is on average 60–80 cm. Air temperature and insulation properties of snow are the main factors that influence the bog freezing. Hummocks freeze out as deep as 63–65 cm, which corresponds to the depth of their seasonal thawing in the warm period of the year, and adjoin the permafrost. The greatest depth of freezing of the swamplands is 82 – 87 cm, with an average of 68 cm. The frozen layer at swamplands thaws out from both its upper and bottom sides. The melting of the frozen layer at hummocks occurs only from the bog surface with an average intensity of 0,51 cm/day.

Hydrological regime, water availability and land use/land cover change impact on the water balance in a large agriculture basin in the Southern Brazilian Amazon

2021 ◽  
Vol 108 ◽  
pp. 103224
Author(s):  
Tárcio Rocha Lopes ◽  
Cornélio Alberto Zolin ◽  
Rafael Mingoti ◽  
Laurimar Gonçalves Vendrusculo ◽  
Frederico Terra de Almeida ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Water Balance ◽  
Land Cover Change ◽  
Water Availability ◽  
Hydrological Regime ◽  
Brazilian Amazon ◽  
Land Use Land Cover ◽  
Change Impact

scholarly journals Assessment of the Water Quality of Jatiluhur Reservoir, the Downstream of Citarum Cascade River, Using Selected Physico-Chemical Parameters

2014 ◽  
Vol 10 (1) ◽  
Author(s):  
Lieza Corsita ◽  
Arwin Arwin ◽  
Barti Setiani Muntalif ◽  
Indah Rachmatiah Salami
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Water Level ◽  
Hydrological Regime ◽  
Quality Parameters ◽  
Biological Data ◽  
Chemical Parameters ◽  
Stream Flows ◽  
Physico Chemical

Physico-chemistry and biological data were investigated  from  October 2010 until April 2011 of Jatiluhur reservoir. A total of six sampling stations were selected for this study. The discharge and hidrological data were obtained from Perum Jasa Tirta II Jatiluhur. The results showed that the hydrological regime in the reservoir Jatiluhur was affected by global phenomenon La Nina events in 2010 and early in 2011. Stream flows were determined during sampling to range from 78  to 482.5 m3/s. The water quality findings were as follows: pH (6.93-8.81), temperature (26.37-30.6°C), dissolved oxygen (0.733-5.2 mg/l), conductivity (2.45-233µmhos/cm), COD (7.36-96.9 mg/l), turbidity (4.063-65.6 NTU), total phosphate (0.002-0.324 mg/l), total nitrogen (0.99-5.96 mg/l), chlorophyl (2.237-43.37 mg/m3), visibility (30-160 cm). The eutrophication was pronounced at Jatiluhur reservoir. Canonical Correspendence Analysis found that some water quality parameters correlated positively with the discharge and the water level.

scholarly journals Lack of recreational fishing compliance may compromise effectiveness of Rockfish Conservation Areas in British Columbia

2018 ◽  
Author(s):  
Dana Haggarty ◽  
Steve J.D. Martell ◽  
Jonathan B. Shurin
Keyword(s):  
British Columbia ◽  
Protected Areas ◽  
Marine Protected Areas ◽  
Fishing Effort ◽  
Area Ratio ◽  
Recreational Fishing ◽  
Conservation Areas ◽  
Fish Stocks ◽  
Ecological Recovery ◽  
Recovery Education

Compliance with spatial fishing regulations (e.g., marine protected areas, fishing closures) is one of the most important, yet rarely measured, determinants of ecological recovery. We used aerial observations of recreational fishing events from creel surveys before, during, and after 77 Rockfish Conservation Areas (RCAs) were established in British Columbia, Canada. There was no evidence of a change in fishing effort in 83% of the RCAs, and effort in five RCAs increased after establishment. Fishing effort in open areas adjacent to the RCAs declined with time and was higher than effort in the RCAs in all 3 years. Next, we used compliance data for 105 RCAs around Vancouver Island to model the drivers of compliance. Compliance was related to the level of fishing effort around the RCA, the size and perimeter-to-area ratio of RCAs, proximity to fishing lodges, and the level of enforcement. Noncompliance in RCAs may be hampering their effectiveness and impeding rockfish recovery. Education and enforcement efforts to reduce fishing effort inside protected areas are critical to the recovery of depleted fish stocks.

scholarly journals Study of climate change effect on water balance in upper Citarum Watershed, the Krueng Cunda Watershed, and the Woske Watershed, Indonesia

2021 ◽  
Vol 930 (1) ◽  
pp. 012074
Author(s):  
A Chalid ◽  
A Mulyadi
Keyword(s):  
Climate Change ◽  
Water Balance ◽  
Water Availability ◽  
Rainy Season ◽  
Water Reservoirs ◽  
Change Effect ◽  
Climate Change Effect

Abstract The community feels the changes in water availability due to climate change will directly impact water availability, especially water availability in rivers, reservoirs and other water reservoirs. The purpose of this analysis is to determine changes in the rainy season shift, changes in mainstay discharge, and the effect of climate change on water balance. The results show a shift in the rainy season and a significant decrease in rainfall during the last ten years. In the Upper Citarum watershed (UCW), there is a change in the maximum and minimum mainstay discharge in the three watersheds. Climate change significantly affects the water balance in a watershed. Meanwhile, in the Krueng Cunda watershed (KCW) and the Woske watersheds (WW), there was a decrease in the value of the water balance, which was the same as the UCW. However, still able to meet the water needs of the population. There was a decrease in the value of the water balance, which was the same as the UCW, but still able to meet the population’s water needs.

scholarly journals Fishery in the Tobol-Ishim interfluve in the neolithic and early metal age

2018 ◽  
Vol 7 (4) ◽  
pp. 182-192
Author(s):  
Viktor Alekseevich Zakh
Keyword(s):  
Water Level ◽  
Bronze Age ◽  
Iron Age ◽  
Life Support ◽  
Hydrological Regime ◽  
Economic Activities ◽  
Deep Foundation ◽  
Metal Age ◽  
North Western

Landscapes of the Tobol-Ishim interfluve were not stable in the Holocene and varied from forests and drowned floodplains at the beginning of the V and III millennia BC to steppificated territories with a lowered water level at the beginning of the Atlantic Period and in the middle of the Subboreal Period, which determined the main types of economic activities, one of them was fishing. Changes in hydrological regime of water bodies influenced the methods of fishing, including the use of different traps. Thus, in the Neolithic, when the water level decreased, the location of settlements in the system river-creek-lake (for example, Mergen 6), a large number of fish bones, bone harpoons, fishing spears, fishing tackles for catching pike and a total absence of plummets were indicative of individual fishing for large fish and, perhaps, of stop net fishery, which was facilitated by a decrease in the width of watercourses and tombolos. Stop net (stake net) fishery led to a settled lifestyle of the population, collective activities and the emergence of long-term settlements with deep foundation pits of dwellings. When the water level in rivers and lakes increased and floods became more frequent, the life support system changed, the population began to develop coasts more widely, its mobility increased, and they started to build framed above-ground dwellings. Following those changes, biconic, cigar-shaped, and corniculate plummets emerged in the Tobol River Basin and on the adjacent western and north-western territories in the III and early II millennium BC. When the water level was high, it was efficient to fish using traps, seines and, probably, nets, although the latter could also be used in drive hunting for shedding geese and ducks. Subrectangular plummets with one or two ties for fastening, and disk-shaped plummets with a tie in the center had been prevailing since the beginning of the II millennium BC; they existed until the first third of the I millennium BC. This period, the transition time from the Bronze Age to the Early Iron Age, is characterized by the absence of clay plummets, while there are large accumulations of fish scales and bones in the settlement layers. We can suppose that the population of that time (local Late Bronze Age population, mixed with northern migrants who made utensils with cross ornamentation) switched from net fishing to stop net fishing.

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