scholarly journals MONITORING OF GLYCOGEN CONTENT OF PREDATORY FISH SPECIES AT THE JUVENILE STAGE OF DEVELOPMENT DUE TO CHANGES IN THE TEMPERATURE AND OXYGEN REGIME OF THE RESERVOIR

2021 ◽  
pp. 49-61
Author(s):  
N.E. Grynevych ◽  
O.M. Vodianitskyi ◽  
O.A. Khomiak ◽  
M.M. Svitelskyi ◽  
V.S. Zharchynska
Keyword(s):  
Fish Species ◽  
Glycogen Content ◽  
Juvenile Stage ◽  
Predatory Fish ◽  
Stage Of Development ◽  
Oxygen Regime

CHARACTERISTICS OF FREE-RADICAL PROCESSES IN THE ORGANISMS OF SOME PREDATORY FISH SPECIES IN DIFFERENT SEASONS OF THE YEAR

2017 ◽  
pp. 117-123
Author(s):  
Nikolay Aleksandrovich Pudovkin ◽  
Peter Vladimirovich Smutnev
Keyword(s):  
Fish Species ◽  
Catalase Activity ◽  
Perca Fluviatilis ◽  
Selenium Concentration ◽  
The Body ◽  
Predatory Fish ◽  
Volga River ◽  
Silurus Glanis ◽  
Average Value ◽  
Pike Perch

The authors of the article have studied the content of the elements of anti-oxidant system (malondialdehyde, catalase, selenium) in tissues of the internal organs (gills, intestine, muscles, liver, swimbladder, scales) in some species of predatory fish (pike Esox lucius (L., 1758), perch Perca fluviatilis (L., 1758), pike-perch Sander lucioperca (L., 1758), catfish Silurus glanis ) widespread in the basin of the Volga river in the Saratov region. The lowest concentration of malondialdehyde in organisms of the studied fish species is observed in fall and winter; the highest - in spring and summer. Catalase activity in gills tissue of a pike raised in 11.8%, cat-fish - 9.1%, pike-perch - 7.5%, perch - 7.8%. In fall (compared to winter) enzyme activity lowering in gonads of pike-perch makes 16.3%, in gonads of perch - 14.4%. In other tissues there were not observed any evident changes of catalase activity. Fish species under consideration are listed according to the average value of selenium concentration in organisms, µg/g: pike (0.208) > catfish (0.207) > pike-perch (0.196) > perch (0.178). According to the average value of the selenium accumulation in the body in different season all the studied species can be placed in the following order, µg/g: winter-pike (0.132) > pike-perch (0.136) > perch and catfish (0.142); spring - pike-perch (0.190) > perch (0.191) > pike (0.208) > catfish (0.209); summer - perch (0.186) > pike-perch (0.190) > catfish and pike (0.203); autumn - perch (0.193) > pike-perch (0.268) > > catfish (0.274) > pike (0.289).

The issue of assessment of efficiency of works on land reclamation fisheries in inland waters of Russia

2021 ◽  
pp. 8-20
Author(s):  
Andrey Dmitrievich Bykov ◽  
Svetlana Yuryevna Brazhnik
Keyword(s):  
Fish Species ◽  
Land Reclamation ◽  
Long Term Results ◽  
Predatory Fish ◽  
Federal State ◽  
Inland Waters ◽  
Ecological Group ◽  
Spawning Grounds ◽  
Commercial Fish

The article considers the issue of assessing the long-term results of work on fisheries reclamation in inland waters of fisheries significance in Russia, carried out by the branches of the Federal State Budgetary Institution “Glavrybvod” on the state task in terms of their effectiveness. The relationship between dredging and clearing of watercourse beds and the dynamics of the number of producers of semi-navigable and non-aquatic fish in these rivers during spawning migrations has not been established. With long-term mowing of wetland vegetation in the shallow waters of reservoirs, deltas of large rivers and estuaries, there is no increase in their commercial fish productivity. A number of examples show the opposite effect of this type of work, which leads to a local deterioration of the ecological state of these reservoirs. At the same time, the repeatedly proven method of combating higher aquatic vegetation in the reservoirs of the south of Russia in low water conditions as biomelioration, based on the introduction of fish, consumers of autotrophic products by regional branches of the Federal State Budgetary Institution “Glavrybvod” is practically not used. When installing artificial spawning grounds in the littoral zone of reservoirs, regular ichthyological monitoring of the effectiveness of spawning on them is not carried out. There are no reliable data confirming the significant positive impact of artificial spawning grounds on the population dynamics of commercial fish species of the limnophilic ecological group under conditions of significant spring water level depletion in Russian reservoirs. When catching predatory and low-value fish species in water bodies, legal obstacles arise due to the fact that the volume of seizure of predatory fish includes commercial objects for which the ODE is established annually and their catch is already carried out according to industrial quotas.

scholarly journals Nursery habitat availability limits adult stock sizes of predatory coastal fish

2013 ◽  
Vol 71 (3) ◽  
pp. 672-680 ◽  
Author(s):  
Göran Sundblad ◽  
Ulf Bergström ◽  
Alfred Sandström ◽  
Peter Eklöv
Keyword(s):  
Fish Species ◽  
Generalized Additive Models ◽  
Nursery Habitat ◽  
Additive Models ◽  
Predatory Fish ◽  
Habitat Availability ◽  
Adult Density ◽  
Habitat Protection ◽  
Nursery Habitats ◽  
Population Sizes

Abstract Habitat protection is a strategy often proposed in fisheries management to help maintain viable populations of exploited species. Yet, quantifying the importance of habitat availability for population sizes is difficult, as the precise distribution of essential habitats is poorly known. To quantify the contribution from coastal nursery habitats to exploited fish population sizes, we related adult density to the amount of nursery habitat available for 12 populations of the two dominant predatory fish species in a 40 000-km2 archipelago area of the Baltic Sea. Habitat distribution was mapped using three conceptually different techniques, Maxent, generalized additive models, and random forest, using spawning and 0-group point samples. Adult densities were estimated from gillnet surveys. Regressions demonstrated no evident effect from fishing, whereas habitat availability had a positive effect, explaining almost half of the variation in population sizes of both species. This result shows that a substantial proportion of the potential production of adult fish can be estimated by mapping essential nursery habitats distribution. Responses were non-linear, indicating that habitat protection has largest effects where there is little available habitat. By demonstrating the importance of habitat limitation of two exploited fish species, we provide quantitative support to the benefits of habitat protection for fisheries.

Methylmercury levels in predatory fish species marketed in Canada

2004 ◽  
Vol 21 (9) ◽  
pp. 849-856 ◽  
Author(s):  
Don S. Forsyth * ◽  
V. Casey ◽  
R. W. Dabeka ◽  
A. McKenzie
Keyword(s):  
Fish Species ◽  
Predatory Fish

scholarly journals MERCURY CONTENT IN MUSCLE TISSUE OF EUROPEAN GRAYLING (THYMALLUS THYMALLUS (L.)) IN THE RIVERS OF THE VOLOGDA REGION

2018 ◽  
pp. 35-40
Author(s):  
A. S. Komarova ◽  
E. V. Ugryumova ◽  
N. Yu. Tropin ◽  
A. E. Shilova ◽  
A. A. Sokolova ◽  
...  
Keyword(s):  
Muscle Tissue ◽  
Fish Species ◽  
Mercury Concentration ◽  
Mercury Content ◽  
Water Bodies ◽  
Predatory Fish ◽  
Average Content ◽  
Thymallus Thymallus ◽  
European Grayling ◽  
Vologda Region

The article presents information about the mercury content in the muscle tissue of the European grayling Thymallus thymallus (L.) in 11 rivers of the Vologda region (Tagazhma, Vozhega, Votcha, Kostyuga, Tiksna, Sheben’ga, Pyrnug, Zemtsovka, Yurmanga, Bol’shaya Rechka and Yontala) for the period of 2011–2015. The average content of toxicant ranged from 0,04 mg/kg in individuals of the river Sheben’ga up to 0,21 mg/kg in the rivers Yurmanga and Bol’shaya Rechka. Four fish noted an excess of the permissible level of sanitary and hygienic standards (SanPiN 2.3.2.1078-01. 2.3.2.) for non-predatory fish species (0,3 mg/kg). Young grayling contains an average of 0,06–0,10 mg/kg mercury in muscle tissue, individuals five to six years old contain 0,26 and 0,27 mg/kg, respectively. A comparison of the level of mercury concentration in the muscle tissue of European grayling with that of other fish species showed that the Hg content does not go beyond the revealed background values for water bodies of the Vologda region.

scholarly journals Efficiency of Sonar Fish Protection Device at the Kokaral Dam of the Small Aral Sea

2021 ◽  
Vol 7 (1) ◽  
pp. 158-176
Author(s):  
S. Е. Sharakhmetov ◽  
◽  
T. R. Barakbayev ◽  
T. O. Adayev ◽  
◽  
...  
Keyword(s):  
Fish Species ◽  
Crucian Carp ◽  
Aral Sea ◽  
Predatory Fish ◽  
Control Fish ◽  
Protection Device ◽  
Pike Perch ◽  
Catch Per Effort ◽  
And Control ◽  
Fish Protection

The study aimed to assess the efficiency of the pilot hydro-acoustic (sonar) fish protection device (SFPD) installed at the Kokaral Dam of the Small Aral Sea. For this purpose, between August 27 and September 5, 2020 experimental and control fish catching was carried out using fixed fishing nets (30×60 mm mesh). The SFPD’s effectiveness was assessed based on the amount and species diversity of the caught fish with and without the SFPD operating. Fish behavior and distribution were monitored using an echo sounder. In terms of quantity, 173 fish were caught with the SFPD off, and 94 with the SFPD on. In terms of biomass, the values were 37.5 kg and 27.6 kg, respectively. With the SFPD off, the ichthyofauna composition was represented by 12 fish species: carp, crucian carp, roach, ide, bream, common rudd, saber carp, snakehead, pike perch, perch, pike, and asp. With the SFPD on, roach and ide were absent in the catch, and the quantity of common rudd significantly decreased. In both catches, the quantity of carp and crucian carp was similar; bream and saber carp specimen were sporadic. The number of predatory fish (pike, perch, snakeheads, and pike perch) in the catches increased. Asp was absent in the net catches also; however, this fish species represents the main object of amateur hook and line fishing. Based on the catch-per-effort unit, it can be concluded that whereas the SFPD observed efficiency for small non-predatory fish like ide, roach, and common rudd was 95%, it was 0% for large non-predatory fish (carp and crucian carp); and negative for predatory fish.

scholarly journals Effects of the 2016 El Niño on the Galapagos artisanal coastal fin-fish fishery

2018 ◽  
Author(s):  
Jose R Marin Jarrin ◽  
Pelayo Salinas-de-León
Keyword(s):  
Climate Change ◽  
Fish Species ◽  
El Niño ◽  
El Nino ◽  
Predatory Fish ◽  
Trophic Chain ◽  
El Niño Events ◽  
Catch Composition ◽  
The Impact ◽  
El Nino Events

El Niño events heavily influence physical characteristics in the Tropical Eastern Pacific and lead to a decrease in nutrient and phytoplankton concentrations and to variation in the composition of the marine trophic chain. However, El Niño events can also provide an opportunity to evaluate the possible effects climate change may have on marine ecosystems. The Galapagos Marine Reserve coastal fin-fish fishery supports approximately 400 fishers that target species that include benthic/demersal predatory fish such as the endemic Galapagos whitespotted sandbass (Paralabrax albomaculatus), the regional endemic sailfin grouper (Mycteroperca olfax) and mottled scorpion fish (Pontinus clemensi), and the misty grouper (Hyporthodon mystacinus). The first two species are listed as vulnerable and endangered, respectively, on the IUCN red list of threatened species. Despite their potential effects on the biota, at present it is unclear how El Niño events influence artisanal fin-fish fisheries in the Galapagos. To study the impacts of El Niño events on the fishery, numerical percentage catch composition at the largest dock in Santa Cruz Island was recorded during March and April 2013, 2014 and 2016 and compared. Compositions were significantly different between 2016 and both 2013 and 2014, but not between 2013 and 2014. These differences appear to have been due to the appearance of uncommon demersal/benthic predatory fish such as Grape eye seabass (Hemilutjanus macrophthalmos) and Pacific dog snapper (Lutjanus novemfasciatus). Size frequency distributions also varied, with significantly larger sizes of several species observed in 2016 when compared to 2013 or 2014. These changes in catch composition and size may be a product of a reduction in nutrient concentration and primary production that led to an increase in water clarity and decrease in prey biomass that forced these benthic fish species to change their feeding behavior and strike at baits that usually would not be easily detected. Because of the conservative life history many of these benthic predatory fish exhibit and the absence of any form of management for fish species in the GMR, El Niño events may have profound effects on their populations due to the elimination of the largest individuals. Management actions, such as size and catch limits and closures, directed at reducing the impact of the fishery on these important fish populations in the near- (El Niños) and long-term (climate change) future should be encouraged.

Vulnerability, Stability, and Coherence of the Fish Community in Lake Superior

1987 ◽  
Vol 44 (S2) ◽  
pp. s404-s410 ◽  
Author(s):  
Y. Cohen ◽  
J. N. Stone ◽  
T. L. Vincent
Keyword(s):  
Fish Species ◽  
Spectrum Analysis ◽  
Structural Changes ◽  
Lake Trout ◽  
Lake Superior ◽  
Sea Lamprey ◽  
Dominant Frequency ◽  
Vulnerability Analysis ◽  
Predatory Fish ◽  
Before And After

Vulnerability analysis and spectrum analysis were found useful in examining potential structural changes in fisheries systems influenced by large perturbations. In the 1950's the Ontario fisheries of Lake Superior experienced a major perturbation due to invasion by sea lamprey (Petromyzon marinus). Vulnerability analysis indicated that invasion by sea lamprey and the consequent shifting of the fisheries to more intensive fishing on lower trophic level species resulted in higher vulnerability of the predatory fish species; i.e. likelihood of extinction increased. Spectrum analysis was then applied to the yield series of five fish species from Lake Superior. Analysis of the data before and after invasion by sea lamprey indicated major structural changes in the fishery: (1) except for lake trout (Salvelinus namaycush), either the dominant amplitude, the dominant frequency, or both decreased; (2) partial coherencies between pairs of yield series changed after the invasion; (3) lake whitefish (Coregonus clupeaformis) and lake trout replaced lake herring (C. artedii) as the species whose fluctuations in commercial yield were most highly synchronized with those of the other species of commercial importance.

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