scholarly journals Features of allometric growth and structure of settlements for Mya uzenensis (Bivalvia: Myidae) in different areas of littoral zone in the Tauiskaya Guba Bay, Okhotsk Sea

2020 ◽  
Vol 200 (2) ◽  
pp. 364-376
Author(s):  
V. S. Zharnikov
Keyword(s):  
Environmental Conditions ◽  
Littoral Zone ◽  
Okhotsk Sea ◽  
Allometric Growth ◽  
Shell Size ◽  
Commercial Stock

Settlements of bivalve Mya uzenensis are investigated in four littoral areas of the Tauiskaya Guba Bay with different environments. Their density varied from 20 to 194 ind./m2 (518–9680 g/m2) depending on habitat. On suitable soils, the settlements occupied 25–40 % of the littoral zone; the mollusks were distributed mostly in mosaic spots with size 0.5–5.0 m2. Stable settlements in the areas with favorable environmental conditions in the Ola estuary and Vesyolaya Bay were formed by mollusks with shell size of 22.1–91.1 mm and age of 2–14 years. Allometry of the shells growth increased with age until 10 years, then leveled. The stocks of mollusk were assessed for certain areas that allowed to recommend for annual landing 158.4 t of M. uzenensis (7 % of commercial stock).

scholarly journals ALLOMETRIC GROWTH AND LIFE EXPECTANCY OF THE BIVALVE DIDACNA BARBOTDEMARNYI (GRIMM, 1877)

2019 ◽  
pp. 20-25
Author(s):  
Marina Vladimirovna Khlopkova
Keyword(s):  
Growth Rate ◽  
Life Expectancy ◽  
Environmental Conditions ◽  
Allometric Growth ◽  
Annual Increase ◽  
Second Stage ◽  
Condi Tions

Allometric characteristics, at the second stage of mollusk growth, more accurately reflect the environmental condi-tions. In assessing the growth of mollusks, it is found that the largest annual increase in the length of the shell is ob-served up to 2,5 years. Revealed has been that Didacna barbotdemarnyi (Grimm, 1877) in moderate environmental conditions after two years of growth comes to maturity, and after 6 years the growth rate slows down. The formation of shells on the principle of negative allometry b < 1 is characteristic for the inhabitants of hard sand-shell and silt-shell soils.

scholarly journals Spatial and temporal variation of fish assemblage associated with aquatic macrophyte patches in the littoral zone of the Ayapel Swamp Complex, Colombia

2017 ◽  
Vol 29 (0) ◽  
Author(s):  
Carlos Mario Marín Avendaño ◽  
Néstor Jaime Aguirre Ramírez
Keyword(s):  
Temporal Variation ◽  
Environmental Conditions ◽  
Fish Assemblage ◽  
Littoral Zone ◽  
Aquatic Macrophyte ◽  
Abundant Species ◽  
Assemblage Structure ◽  
Spatial And Temporal Variation ◽  
Suitable Habitat ◽  
Fish Assemblage Structure

Abstract: Aim The purpose of the present study was to examine spatial and temporal variation in fish assemblage structure associated with aquatic macrophytes in the littoral zone of the ASC. Methods Specimens were caught between January 2008 and February 2009, over four limnimetric moments, using both cast net and seine net. Data on the temperature, electrical conductivity, pH and dissolved oxygen was recorded for the characterization of the water mass in the sites. Results A total of 34,151 specimens from 44 species were collected. The most abundant species were Eigenmannia virescens, Astyanax caucanus, Astyanax fasciatus, Roeboides dayi and Cyphocharax magdalenae, which together accounted for more than 75% of the sample. Temporal and spatial comparisons showed variation in the environmental conditions and highlighted the existence of heterogeneous abiotic conditions (p<0.05). However, the multiple comparisons test showed the existence of homogeneous spatial conditions (p>0.05) regarding the fish assemblage structure. The multivariate analysis showed no significant relationship between existing environmental conditions and the fish assemblage (p=0.04). The analysis also showed the absence of a relationship between the fish assemblage and environmental variables with respect to the flood pulse and sampling sites (p>0.05). Conclusion The uniformity of the fish communities that inhabit aquatic macrophyte patches in the littoral region of the ASC may be related to the availability of suitable habitat in structural terms, that probably supports a more abundant and varied wildlife.

scholarly journals Some results of the pacifc herring studies in the period of winter-spring fshery in the Okhotsk Sea

2018 ◽  
Vol 195 ◽  
pp. 140-145
Author(s):  
S. V. Loboda
Keyword(s):  
Stock Assessment ◽  
Okhotsk Sea ◽  
Additional Method ◽  
The North ◽  
Method Of Evaluation ◽  
Commercial Size ◽  
Commercial Stock

Pacifc herring stock was evaluated for two fshery districts in the Okhotsk Sea (North-Okhotsk and West-Kamchatka subzones) on the data collected during winter-spring fshery in 2017. The method of evaluation is described, quality of the materials collected aboard commercial fshing vessels is discussed, and the assessments are presented. Taking into account the areas of the districts and density of fsh distribution, the stock of herring is counted as 1854.92. 103 t (7390.36 . 106 ind.), mostly within the North-Okhotsk subzone (64.6 % by biomass). More than 90 % of this stock was formed by herring of commercial size that means that its juveniles were not counted properly by commercial catches. So, the stock assessment on the data of commercial catches could be used as additional method of the commercial stock monitoring, beyond the data of scientifc surveys.

scholarly journals Reproduction of the Androgenetic Population of the Asian Corbicula Clam (Bivalvia: Cyrenidae) in the Northern Dvina River Basin, Russia

Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 316
Author(s):  
Yulia V. Bespalaya ◽  
Olga V. Aksenova ◽  
Alexander V. Kropotin ◽  
Alexander R. Shevchenko ◽  
Oksana V. Travina
Keyword(s):  
Environmental Conditions ◽  
Power Plants ◽  
Size Structure ◽  
Water Discharge ◽  
Thermal Power ◽  
Shell Size ◽  
Management Measures ◽  
Winter Temperatures ◽  
Reproduction Period ◽  
Corbicula Clam

The Corbicula clam is one of the most successful invaders of aquatic ecosystems and has invaded all continents except Antarctica. The natural dispersion of Corbicula seems to be limited by low winter temperatures that fall below the lower lethal temperatures (0 to +2 °C). However, Corbicula can be found in colder regions, taking refuge in waters heated by thermal power plants. The purpose of this investigation was to study the gonadal histology, reproductive cycle, and the seasonal changes of shell size structure of the Corbicula clam populations in the warm water discharge of the Arkhangelsk thermal power plant (Northwest Russia). Samples were collected monthly from January 2017 to December 2018 and processed using traditional histological and morphological techniques. The number of reproductive periods varied from year to year. It was established that the Corbicula clam has a continuous reproduction period which may be adaptive in unstable environmental conditions. This reproductive strategy is probably aimed at increasing the reproductive success of the population. Our data expand the understanding of reproductive features of the Corbicula clam in harsh environmental conditions. These results could be applied to control, monitoring, and management measures.

scholarly journals The Distribution and Influence of the Introduced Alga Colpomenia Bullosa in the Rocky Intertidal

2021 ◽  
Author(s):  
◽  
Daniel Francis McNaughtan
Keyword(s):  
New Zealand ◽  
Spatial Variation ◽  
Environmental Conditions ◽  
Desiccation Tolerance ◽  
Brown Alga ◽  
Littoral Zone ◽  
Rocky Intertidal ◽  
Macroalgal Species ◽  
Native Communities ◽  
Wide Range

<p>The brown alga Colpomenia bullosa was first observed in New Zealand more than 20 years ago, yet very little is known about its current intertidal distribution or possible effects it may be having on native communities. This study addresses some of these issues. Surveys indicate little spatial variation in abundance around the Wellington region, however, the sporophytic crustose phase is restricted to pools high in the littoral zone while the gametophytic upright has a low- to sub-littoral distribution. Physiology experiments indicate that C. bullosa can tolerate a wide range of environmental conditions, but the crustose phase has a poor desiccation tolerance. A series of tranplant and competition experiments confirmed this and suggested that the crustose phase requires some level of facilitation by molluscan herbivores in order to become established. These experiments also revealed that crustose C. bullosa does not compete well against more upright macroalgal species. The effects of this introduced algae on native communities are likely to be minimal given its restricted intertidal distribution and its inability to compete against more upright species.</p>

scholarly journals Size-age structure of oyster Crassostrea gigas in the Losos Bight (Aniva Bay, Okhotsk Sea)

2020 ◽  
Vol 200 (4) ◽  
pp. 873-883
Author(s):  
A. Ch. Kim ◽  
R. T. Gon
Keyword(s):  
Age Structure ◽  
Crassostrea Gigas ◽  
Total Weight ◽  
Okhotsk Sea ◽  
Shell Size ◽  
Aniva Bay

Data on age structure, shell size (height, length, thickness) and weight of oyster Crassostrea gigas in the Losos Bight (Aniva Bay, Okhotsk Sea) are presented on results of the surveys conducted in 2018 and 2019. The size-age key for the total weight is plotted. The size-age structure is compared with oysters from other habitats.

Description of Saccharina japonica commercial stock in the Aniva Bay (Okhotsk Sea) //

2014 ◽  
Vol 178 (3) ◽  
pp. 116-123
Author(s):  
Natalia M. Aminina ◽  
Tatiana I. Vishnevskaya ◽  
Dmitry A. Galanin ◽  
Anna R. Repnikova ◽  
Olga N. Guruleva
Keyword(s):  
Okhotsk Sea ◽  
Aniva Bay ◽  
Commercial Stock

scholarly journals The Distribution and Influence of the Introduced Alga Colpomenia Bullosa in the Rocky Intertidal

2021 ◽  
Author(s):  
◽  
Daniel Francis McNaughtan
Keyword(s):  
New Zealand ◽  
Spatial Variation ◽  
Environmental Conditions ◽  
Desiccation Tolerance ◽  
Brown Alga ◽  
Littoral Zone ◽  
Rocky Intertidal ◽  
Macroalgal Species ◽  
Native Communities ◽  
Wide Range

<p>The brown alga Colpomenia bullosa was first observed in New Zealand more than 20 years ago, yet very little is known about its current intertidal distribution or possible effects it may be having on native communities. This study addresses some of these issues. Surveys indicate little spatial variation in abundance around the Wellington region, however, the sporophytic crustose phase is restricted to pools high in the littoral zone while the gametophytic upright has a low- to sub-littoral distribution. Physiology experiments indicate that C. bullosa can tolerate a wide range of environmental conditions, but the crustose phase has a poor desiccation tolerance. A series of tranplant and competition experiments confirmed this and suggested that the crustose phase requires some level of facilitation by molluscan herbivores in order to become established. These experiments also revealed that crustose C. bullosa does not compete well against more upright macroalgal species. The effects of this introduced algae on native communities are likely to be minimal given its restricted intertidal distribution and its inability to compete against more upright species.</p>

Vibration Isolator System for Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 182-183
Author(s):  
K. Ohi ◽  
M. Mizuno ◽  
T. Kasai ◽  
Y. Ohkura ◽  
K. Mizuno ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Magnetic Fields ◽  
Environmental Conditions ◽  
Vibration Isolator ◽  
Air Conditioners ◽  
Vibration Isolators ◽  
Large Size ◽  
Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

Sign in / Sign up

Export Citation Format

Share Document