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PUBLISHED DATE: - 09-11-2024
DOI: -
https://doi.org/10.37547/tajabe/Volume06Issue11-03
PAGE NO.: - 9-15
ECOLOGY OF WATER TYPES IN THE
MIRZACHUL REGION (PONTASTACUS
LEPTODACTYLUS (ESCHSCHSCHOLTZ,
1823): HABITATS AND INDICATOR
CHARACTERISTICS IN THE STUDY OF
WATER TYPES
I.A. Tuynazarova
Lecturer at Jizzakh polytechnic institute, Jizzakh, Uzbekistan
INTRODUCTION
The study of the ecology of river crab in the
Mirzachul region (Pontastacus leptodactylus
(Eschschscholtz, 1823) is of particular importance
for understanding the state of aquatic ecosystems
in this region. This species, Pontastacus
leptodactylus, plays an important role in the food
chains of freshwater systems, which affects the
structure of communities and the distribution of
organisms
in
water
bodies.
Pontastacus
leptodactylus is sensitive to changes in water
quality and environmental conditions, making it an
important bioindicator for assessing the condition
of water bodies and identifying environmental
problems.
Understanding
the
ecological
advantages and requirements of this species allows
for the acquisition of information for managing the
state of aquatic ecosystems, identifying threats to
populations, and developing measures to protect
them.[6,14]
A review of existing studies shows that ecological
studies of Pontastacus leptodactylus indicate that
this species is widespread in Eurasia, preferring
RESEARCH ARTICLE
Open Access
Abstract
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clean and slightly saline water bodies with sandy or
clay soils. The literature describes the
characteristics of its life cycle, including water
temperature, oxygen content, and requirements for
mineral composition, highlighting its sensitivity to
water quality. As a bioindicator, P. leptodactylus is
used in a number of studies to assess the ecological
state of water bodies: its presence and the state of
populations often indicate the stability and health
of the aquatic environment. A number of
researchers are also considering its sensitivity to
pollution by organic matter, heavy metals, and
temperature fluctuations, which allows it to be
used for environmental monitoring.[5,6,9,10].
Environmental factors The population of
Pontastacus leptodactylus is affected by a variety of
environmental factors, including:
- water temperature: the optimal temperature
values for this species are in the range of 18-24°C,
and increasing the temperature can cause stress
and reduce activity.
- pH of water: this cancer prefers a neutral or
slightly hydroxide environment with a pH of 6.5 to
8.5, as changes in pH can affect metabolism and
integument permeability.
- Oxygen content: A high concentration of
dissolved oxygen (at least 6 mg/l) is necessary to
maintain normal physiological activity and growth,
and a lack of oxygen can lead to a decrease in
population numbers.
- Mineral composition: water mineralization plays
an important role in metabolic processes and the
health of this species; The values from 200 to 800
mg/L are considered acceptable. These factors
determine the habitability of ponds for Pontastacus
leptodactylus and allow for an assessment of the
state of the environment.[4]
The purpose of this study is to investigate rivers in
the Mirzachul region. Syrdarya, Zominsuv, Sangzor
and Guralash canals; The study of the habitat and
indicator
characteristics
of
Pontastacus
leptodactylus in the Mirzachul, South Mirzachul,
Dustlik, Jizzakh main, and Arnasay reservoir outlet
channels [Fig. 1]. This study aims to assess the
condition of water bodies using this species as a
bioindicator. Identifying factors influencing its
population allows for a better understanding of the
ecological state of local aquatic ecosystems,
developing recommendations for their protection
and sustainability conservation.[3,12]
Figure 1. The distribution of hydrobionts in populations of rivers and canals in the Mirzachul
region (n= 10, m
2
/piece)
0
2
4
6
8
10
12
14
16
Syrdarya
river
Zaminsuv Sangzor
river
G'uralash Mirzachul
canal
South
Mirzachul
canal
Dustlik
canal
Jizzakh
main
canal
Arnasoy
reservoir
outlet
Canal
Pontastacus leptodactylus
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Description of the research area of materials and
methods: The characteristics of water bodies in the
Mirzachul region and their main ecological
parameters: the Mirzachul region, the Mirzachul
plain, is located between the Kyzylkum desert and
the Syr Darya. The northern edge of this region,
adjacent to the wide plains, corresponds to the
border of Kazakhstan, while the southern border
runs along the administrative border of Tajikistan
and Uzbekistan. To the south of the Mirzachul
region lies the Turkestan mountain range, the
Mountains of Malguzar and Nurata, and the
Sangzar Valley. The Mirzachul Plain, Turkestan, the
northern slopes of the Malguzar and Nurata
Mountains, and the Sangzar Valley are part of the
Mirzachul Natural and Geographical Region.[3]
Administratively,
the
Mirzachul
region
corresponds to the Syr Darya and Jizzakh regions.
The northern part of the Mirzachul plain is 231
meters above sea level, the central part is 400-450
meters above sea level, and the Syr Darya coast is
240-250 meters above sea level. The highest
elevations of the Turkestan mountain range are
4000 meters above sea level. Depending on the
fauna and natural regions of the Mirzachul natural
and geographical region, it changes from plains to
mountains, is characterized by a continental
climate with hot and dry summers and moderately
cold winters. The area's water bodies include slow-
flowing rivers and canals, as well as artificial water
bodies. These water bodies serve as the primary
habitat for Pontastacus leptodactylus, whose
species adapt to various abiotic conditions. The
main ecological parameters of water bodies in the
Mirzachul region include:
- water temperature: varies depending on the
season and time of day, usually in the range of 10-
30 °c.
-pH level: from slightly acidic to slightly alkaline, in
the range of 6.5-8.5.
- Dissolved oxygen content: the indicators typically
range from 5 to 12 mg/L, depending on the water
activity and the level of vegetation cover.
- Water mineralization: the
degree of
mineralization can vary from 200 to 1000 mg/l,
reflecting the diversity of the chemical composition
of water bodies.
- Water transparency: varies from 0.5 to 2 meters
depending on the degree of suspended particles.
These parameters vary depending on the season
and local pollution sources, including the agrarian
impact that can affect the hydrobiota, including the
Pontastacus leptodactylus population.
Sampling and material processing methods for
identifying
populations
of
Pontastacus
leptodactylus Sampling was performed manually
and using a trap set in areas with a high probability
of their survival. The sampling frequency to
account for seasonal changes is monthly. The traps
were left for 24 hours, after which they were
removed and the samples were recalculated.[8,14,
15]. The collected samples were placed in
containers that preserve environmental conditions
to minimize stress factors (Fig. 2). Each sample of
Pontastacus leptodactylus was measured and
weighed to determine the biomass. The samples
were stored in ethanol solution, if necessary, for
further morphological and genetic research.
Methods of measuring abiotic factors The following
methods of measurement were used to assess
environmental conditions:
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Figure 1. The distribution of hydrobionts in populations of rivers and canals in the Mirzachul
region (n= 10, m
2
/piece)
- the water temperature was measured using a
digital thermometer at a distance of 1 meter from
the water surface.
- the pH of the water was determined using a
calibrated portable pH meter before the
measurements began.
- The amount of dissolved oxygen was measured
using an oximeter, which allows for accurate values
at the sampling site.
Water mineralization was determined using a
conductor that measured water conductivity and
converted to salt concentration values.
The transparency of the water was measured using
a Sequoia disc, lowered to different depths until
visibility was completely lost, which gave an
indication of the degree of suspended particles in
the water. Correlation and regression analysis
methods were used to analyze the abundance of
Pontastacus leptodactylus and their correlation
with environmental parameters. The main stages
of the analysis were as follows:
The Shannon Index and Simpson's Index were used
to assess biodiversity through population
indicators for data analysis, allowing for an
assessment of species diversity and the uniformity
of species distribution.[11]
The ecology of Pontastacus leptodactylus in
various aquatic species of the Mirzachul region is
an interesting area of research, as this species is an
indicator, meaning its abundance and physiological
parameters can reflect the state of the aquatic
ecosystem. Features of habitats Pontastacus
leptodactylus inhabits rivers, lakes, and artificial
water bodies (such as canals and water bodies) in
various water types in the Mirzachul area. These
water bodies differ in a number of parameters,
such as oxygen content, mineral composition,
temperature, pH level, transparency, and
anthropogenic load level.
Rivers: water Pontastacus leptodactylus, which is
often high in oxygen and high in water exchange,
exhibits more stable numbers. Optimal conditions
include a temperature from 15 to 25°C and a
dissolved oxygen level from 6 to 12 mg/l. The
transparency and steady flow of water also
contribute to a good oxygen regime and stable
mineral composition[1,12].
Lakes: In stable water bodies such as lakes, the
oxygen content may be low, especially during hot
seasons, due to reduced water circulation.
Pontastacus leptodactylus may exhibit decreased
numbers and low activity due to increased
0
2
4
6
8
10
12
14
16
Syrdarya
river
Zaminsuv Sangzor
river
G'uralash Mirzachul
canal
South
Mirzachul
canal
Dustlik
canal
Jizzakh
main
canal
Arnasoy
reservoir
outlet
Canal
Pontastacus leptodactylus
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mineralization and reduced oxygen concentration
under such conditions. However, if the water in the
lake is often refreshed, the species can maintain
their numbers at a normal level[9,14].
Artificial water bodies (channels and water
bodies): These water bodies are often strongly
influenced by humans, such as the flow of
wastewater, resulting in a change in the chemical
composition of the water. High levels of pollutants
and consequent decreased transparency may
worsen conditions for Pontastacus leptodactylus,
which is reflected in decreasing numbers. The
relationship between Pontastacus leptodactylus
and abiotic factors of water bodies The abundance
of Pontastacus leptodactylus in the Mirzachul area
is largely due to several main abiotic factors: water
temperature: the optimal water temperature is 18-
24°C. At temperatures above 25°C or below 10°C,
their number is decreasing, as such conditions
negatively affect human metabolism and activity
levels. Dissolved oxygen: The shrimp requires an
oxygen concentration in the range of 6-12 mg/l. A
decrease in oxygen level (less than 6 mg/L) leads
to a decrease in numbers, as the shrimp is stressed
and may move to more favorable locations.
Mineralization: this species prefers moderate
water mineralization (200-800 mg/L). Excessive
mineralization, especially with high water
hardness, reduces their number, as cancer is less
active and can reproduce less frequently.
pH: The optimal pH range for Pontastacus
leptodactylus is 6.5-8.5. Outside this range, for
example, under acidic conditions (less than 6.5),
their number can be significantly reduced due to
altered water composition and the possibility of
toxic compounds.
According to the flow rate indicators; -0.05-0.015
m/s.
The characteristics of Pontastacus leptodactylus
can serve as an indicator of the ecological state of
Pontastacus
leptodactylus
water
bodies,
depending on environmental conditions. The
abundance of this species and changes in its
physiological state allow us to draw conclusions
about the state of water, its chemical composition,
and the degree of anthropogenic impact. For
example: in water bodies.
DISCUSSION
The discussion on the ecology of Pontastacus
leptodactylus (Eschschscholtz, 1823) in the water
bodies of the Mirzachul region: interpretation of
the obtained data on the abundance and indicator
characteristics of Pontastacus leptodactylus in the
study of water bodies during research on
Pontastacus leptodactylus or river shrimp, it was
noted that its abundance and population density in
the water bodies of the Mirzachul region are
directly related to the ecological conditions of the
water bodies. Key parameters such as water
transparency, mineralization level, dissolved
oxygen content, temperature, pH, and depth have a
significant impact on the distribution and
population
of
this
species.
Pontastacus
leptodactylus prefers an environment with
moderate oxygen content (6-12 mg/L) and
mineralization (200-800 mg/L), which is also
confirmed by field observations. These data
indicate a high sensitivity of Pontastacus
leptodactylus to changes in water quality. The river
crab acts as a type of indicator that is sensitive to
changes in environmental parameters. For
example, with an increase in water pollutants,
especially
nitrogen and
phosphates,
the
population's number and activity decrease, making
Pontastacus leptodactylus a useful biological
indicator of the water div's degree of pollution.
The use of crustaceans in monitoring is associated
with their slow movement and relatively long life
cycle, which allows for more reliable and long-term
data on changes in water bodies. As in other
studies, Pontastacus leptodactylus in Mirzachul has
proven its role in assessing the ecological state of
water bodies and can be used for sanitation
control.
CONCLUSION
Conclusion on the ecology of Pontastacus
leptodactylus in water species in the Mirzachul
region (Eschschscholtz, 1823): the study of the
habitat and indicator characteristics of water
bodies in the Mirzachul region. The study of
Pontastacus leptodactylus in the Mirzachul region
showed that this species of crustaceans is an
important indicator of the state of water bodies in
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the region. The main conclusions are as follows:
1.Pontastacus leptodactylus prefers freshwater
basins with sufficient oxygen and moderate
mineralization. The species is sensitive to changes
in parameters such as dissolved oxygen, water
temperature, and its transparency, making it an
important indicator of the ecological state of water
bodies.
2.
Sensitivity
to
environmental
change:
Pontastacus leptodactylus exhibits high sensitivity
to anthropogenic changes such as pollution and
changes in water chemistry. This species prefers
clean water, and with an increase in pollutants,
their number decreases, especially when the
permissible
level
of
mineralization
and
concentration of dissolved oxygen are exceeded.
3. Features of the indicator: Pontastacus
leptodactylus can serve as a bioindicator for
assessing water quality, as its condition and
abundance reflect the degree of water pollution.
Specifically, the presence of a stable population of
Pontastacus leptodactylus indicates favorable
conditions for other members of the hydrobiota,
while a sharp decline or absence of humans may
indicate a negative environmental impact.
The results showed that the crab is an ecological
valence-bearing organism only in the Syr Darya
and Sangzar rivers. In channels; Mineralization of
water from abiotic factors led to a decrease in the
number of species in the Mirzachul, Southern
Mirzachul, Dustlik, and Arnasay reservoir outlet
channels.
Recommendations for the use of Pontastacus
leptodactylus as an indicator of the state of water
bodies in the Mirzachul region. Water quality
monitoring: the use of Pontastacus leptodactylus in
monitoring programs can improve the accuracy of
assessing the condition of water bodies. Regular
monitoring of the crab population and analysis of
its population reveal the first signs of deterioration
of conditions in the water bodies. Role in
biodiversity assessment systems:
Pontastacus leptodactylus can be included in the
biodiversity system as a key indicator
characterizing the overall state of the ecosystem.
The abundance and distribution of this species may
reflect the balance of the ecosystem and the
presence of negative factors. Comparison with
other indicator species: The combined use of
Pontastacus leptodactylus and other indicator
species, such as mollusks and fish, may be more
useful.
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