scholarly journals Commercial characteristics of semi-anadromus and river fish species on the Dagestan coast of Caspian Sea in 2015

2016 ◽  
Vol 31 (2) ◽  
pp. 85-97
Author(s):  
R.M. Barkhalov ◽  
◽  
N.I. Rabazanov ◽  
A.K. Butayeva ◽  
E.N. Lobachev ◽  
...  
Keyword(s):  
Author(s):  
Edward Vladimirovich Nikitin

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.


Author(s):  
Tatia Kuljanishvili ◽  
Levan Mumladze ◽  
Bella Japoshvili ◽  
Namig Mustafayev ◽  
Shaig Ibrahimov ◽  
...  

The South Caucasus (SC) region is recognized for its high biological diversity and various endemic animal taxa. The area has experienced many fish introductions over the years, but the overall information about non-native fishes in the three SC countries, Armenia, Azerbaijan, and Georgia did not exist. Although these three countries belong to the Kura River drainage, Caspian Sea basin (only the western half of Georgia drains into the Black Sea), the legislative framework for each country regarding introduction of non-native fish species and their treatment is different and poorly developed. The goal of the present study was to make an initial inventory of non-native fish species in the three SC countries, and summarize the existing knowledge as a basis for future risk assessment models and formulation of regional management policies. Here, we present a unified list of 27 non-native species recorded in the wild in Armenia, Azerbaijan, and Georgia. Among these 27 species, eight were translocated from the Black Sea basin to the Caspian Sea basin. Out of these 27 non-native fishes, 15 species have become established (three of them being considered invasive) and six fish species could not survive in the wild.


2018 ◽  
Vol 13 (2) ◽  
pp. 9-21 ◽  
Author(s):  
Marina V. Khlopkova ◽  
Magomedzagid K. Guseynov ◽  
Kais M. Guseynov ◽  
Aysha Sh. Gasanova

Aim. The aim is to study bivalve mollusks of the Dagestan zone of the Caspian Sea as the main feed for all the fish fauna in modern conditions. Material and methods. For the study, are used the materials received in the period of spring-autumn 2015-2017. The collection of material and data processing was carried out according to traditional methods. For the study of nutrition, 30 specimens of each fish species were opened. Such feeding characteristics as the composition of food and the ratio of feed components are given. In the study of shells of bivalve mollusks, the following morphological parameters were measured: length (L), height (H), convexity (Con.), in accordance with the most common measurement technique. Were calculated the allometric coefficients for each year of the life of the individual: the coefficient of elongation (the ratio of height to length), the convexity coefficient (the ratio of convexity to the height). Results. At all periods of the level regime, mollusks are the main food resource of the Caspian Sea. At present they form the basis of the food bolus of the investigated commercial fish species. In June 2017, 25 km north of the city of Makhachkala, after a storm, we found 109 shells of Corbicula fluminalis (O.F. Müller, 1774) (a new invasive atypical species for the investigated aquatorium), the third part of which still had the remains of the ligament. The species was the third most abundant and represented by specimens of all age stages. Conclusions. At present, there are fluctuations in the biomass of the autocolonizers Cerastoderma lamarcki (Reeve), Mytilaster lineatus (Gmelin) and Abra ovata (Philippi), as well as a significant reduction in the range of autochthonous Caspian species, mainly Didacna Eichw. Bivalve mollusks are the main food resource of the Caspian Sea. In conditions of increasing anthropogenic load, further detailed studies of the Caspian's malacofauna are needed.


2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Odilo Noplantino Ajai ◽  
M Sofwan Anwari ◽  
M Dirhamsyah

The condition of Embaloh River is still well maintained, with clear water and a large variety of fishes. This is because the forest around Embaloh River is still dense; there is no deforestation, mining, and palm oil garden. In such a condition, the river is capable of maintaining a large variety of fishes that have not listed yet. Therefore, this research has the purpose of studying the variety of fishes in Embaloh River, and also to categorize the fishes based on their benefits, whether as decorative fishes, to be eaten, or even as a decorative fish and also to be eaten. The research was conducted on the Embaloh River, Banua Ujung Village, Embaloh Hulu District, Kapuas Hulu Regency. Research Data is obtained by the use of fishing equipment such as mesh, Bubu, Sauk, trawler, burst, and Talom. The method of research using the survey method, the selection of observation stations conducted with (purposive sampling) based on consideration of environmental conditions of the water. This location is made 3 (three) stations on the Embaloh River and 1 (one) station is on the lake (oxbow) called Lake Loane. Lake Loane is a stream of the Embaloh River Moreover, fish of species taken from Embaloh River and Loane Lake, which water from Embaloh River flows to, consist of several families of fish; Cobitidae (1 species), Cyprinidae (13 species), Elopidae (1 species), Grynocheilidae (1 species), Helostomatidae (1 species), Osphronemidae (2 species), Polynemidae (1 species), Pristolepididae (1 species), Sisoridae (1 species), and Syngnathidae (1 species).Keywords: Banua Ujung Village, Embaloh River, Fish Species Diversity, Loane Lake.


Author(s):  
Aysha Sh. Gasanova ◽  
Kais M. Guseynov ◽  
Ruslan M. Barkhalov ◽  
Marina V. Khlopkova

The offshore zone of the western coast of the Caspian Sea is one of the most highly productive. Of the 63 species of fish that live in the Caspian Sea, 34 species are found on the Krainovsky coast, 42 % of which are carp. The most numerous is the roach Rutilus rutilus caspicus (Jakowlev, 1870), which makes up 50–86 % of the number of semi-passerine and river fish. The article presents the results of studies of the peculiarities of the biology of the roach Rutilus rutilus caspicus of the Krainovsky coast of the Caspian Sea. The roach is noted in the catches constantly. Her age in the networks ranges from 2 to 10 years. The share of 3-5-year-olds accounts for 81 %. Females in catches make up 66 %, males - 34 %. The parameters of the Bertalanfi equation are characterized by the following values: L =38.8 cm, K = 0.12, t° = -2.67. The fecundity of the roach on average is 30.2 thousand eggs and tends to increase with increasing length and weight of the fish. As the roach grows, the composition of its food changes significantly. The maximum fed roach length from 10 to 20 cm.


Ecohydrology ◽  
2020 ◽  
Vol 13 (3) ◽  
Author(s):  
Jason D. Thiem ◽  
Ian J. Wooden ◽  
Lee J. Baumgartner ◽  
Gavin L. Butler ◽  
Matthew D. Taylor ◽  
...  

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