scholarly journals Optimal methods for identification of dominants for submerged aquatic vegetation on a case of the northwestern Tatar Strait

2020 ◽  
Vol 200 (3) ◽  
pp. 767-788
Author(s):  
A. A. Dulenin
Keyword(s):  
Aquatic Vegetation ◽  
Japan Sea ◽  
Projective Cover ◽  
Visual Methods ◽  
Qualitative And Quantitative ◽  
Tatar Strait ◽  
Sublittoral Zone ◽  
Macrophyte Species ◽  
Northwestern Tatar Strait ◽  
Indices Of Similarity

Dominant species are identified at infracenotic level for aquatic vegetation in the sublittoral zone of the northwestern Tatar Strait (Japan Sea) on the data collected in 2010–2019. Seven different methods of the identifying are considered based both on visual qualitative and quantitative assessments and on instrumental estimations of abundance for 44 macrophyte species. Depending on applied method, 19–25 species (7–22 % of total number of species) are identified as the dominants, including 10 species identified by all methods. List of these 10 species is defined as the core of vegetation that determines its general properties and the species are determined as unconditional dominants, in opposite to other ones identified by at least one method — conditional dominants. All macrophyte species in areas of low abundance do not meet the dominance criteria. All lists of dominants, including those based on visual estimates of projective cover and its physiognomy, are statistically indistinguishable (p = 0.55–0.92, by pairs of lists) and highly similar (Bray-Curtis index 0.80–0.95, Jacquard index 0.65–0.87), with one exception for the list identified by the method of ranking for the average projective cover (indices of similarity with other lists: 0.68–0.71 by Bray-Curtis, 0.46–0.56 by Jacquard). This visual method of projective cover assessment is combined with the procedure of species dividing to dominant and non-dominant groups. Quantitative criteria of projective cover and biomass, by species (thresholds 0.2 and 1.0 kg/m3, respectively) are used for dividing on cenotic and landscape levels and ranking with Brotskaya-Zenkevich index and its modification for projective cover is used for dividing on regional level. Visual methods are available for verification, but the lists of dominants based on visual and instrumental assessments should be mutually verified.

scholarly journals Vertical distribution of bivalves fauna in the northwestern Tatar Strait (Japan Sea)

2020 ◽  
Vol 200 (3) ◽  
pp. 635-655
Author(s):  
Р. A. Dulenina ◽  
A. A. Dulenin
Keyword(s):  
Species Richness ◽  
Vertical Distribution ◽  
Cold Water ◽  
Japan Sea ◽  
Warm Water Species ◽  
Tatar Strait ◽  
Sublittoral Zone ◽  
Depth Ranges ◽  
Northwestern Tatar Strait ◽  
Water Species

General patterns of bivalves distribution by depth in the northwestern Tatar Strait (within Khabarovsk region) are analyzed on the data of 384 trawl, 573 drag, and 1177 diving stations during research surveys in 2003–2016 where the samples were collected with commonly accepted methods. Depths from 0 to 600 m were surveyed. Besides, scientific publications and archival materials related to this area were taken into account. The species richness (y) decreases with depth (x) exponentially from 51 species at 1–20 m to 3 species at 400–600 m that could be approximated satisfactory by the equation y = 31.799. e–0.0502x (r2 = 0.89). Sublittoral and bathial faunas can be separated by cluster analysis of special composition in the depth range 0–150 m and 150–600 m, respectively, with similarity of 0.11 between them. Within these boundaries, 5 local faunas are distinguished: I (< 2 m, the surf zone at the upper boundary of the sublittoral zone), II (2–30 m, the upper sublittoral zone), III (30–150 m, the lower sublittoral zone), IV (150–400 m, the transitional zone) and V (400–600 m, the upper bathyal zone), with similarity between them from 0.14 to 0.36. The upper sublittoral zone has the maximum species richness — 64 species and is the habitat for a «core» of Bivalve fauna with almost ⅔ of its species, preserving the ratio of the main biogeographic groups typical for the researched area. Commercial fishery of scallop Mizuhopecten yessoensis exploited this zone mainly and now is banned to prevent reduction of its stock. Other commercial bivalves, as Callista brevisiphonata, Serripes laperousii, Keenocardium californiense, and Mercenaria stimpsoni, which commercial stocks are estimated in order of 105 t, are also concentrated in this zone but are not landed currently. Portion of moderately cold-water species (wide-boreal and low-boreal) increases and portion of warm-water species (subtropical-boreal and subtropical-low-boreal) decreases with depth, with the slope coefficients of the regressions α = 9.2 ± 4.1 (p = 0.11) and α = –9.6 ± 2.3 (p = 0.03), respectively. The coldwater species are absent in the surf and upper bathyal zones but their portion in other zones is 20–26 %. Rather high portion of boreal-arctic species on shallow depths reflects relative severity of the northwestern Tatar Strait that is the most cold-water area of the Japan Sea. The warm-water species are completely absent in the upper bathyal zone, i.e. at the depths > 400 m. On the other hand, portion of banal species increases and portion of specific species decreases with depth, also portion of rare species increases and portion of mass species decreases with depth, with the slope coefficients α = 9.10 ± 0.49 (p = 0.0003) and α = –4.5 ± 2.5 (p = 0.01), respectively. Vertical distribution of frequent species is rather uniform: 33–57 %. These patterns of the species distribution by zones almost do not change spatially: distribution of different biogeographic groups of species in three coastal areas (47–49о N, 49–51о N, and > 51о N) has no statistically significant differences. Distribution of species richness and composition by depth ranges relates to ecotopic variation (74 % of diversity), to the degree of exploration (22 %), and to the influence of such complex factor as a depth (4 %). Further faunistic studies are recommended in the most diverse areas, as bays, harbours, and capes vicinities with variable grounds and submarine vegetation, in all available depth ranges. Such surveys can provide faunistically representative information on the species wealth. The list of Bivalve mollusk species for the northwestern Tatar Strait can be enlarged possibly in 1/5 if detailed studies of their fauna will be conducted. The fauna on great depths is the most underexplored. The total expected number of bivalve species in this area is at least 120.

scholarly journals Current state of resources for japanese flying squid Todarodes pacificus in the northwestern Tatar Strait (Japan Sea)

2020 ◽  
Vol 200 (3) ◽  
pp. 586-604
Author(s):  
P. A. Dulenina ◽  
E. I. Ustinova ◽  
A. A. Dulenin
Keyword(s):  
Body Weight ◽  
Relative Number ◽  
Japan Sea ◽  
Zooplankton Biomass ◽  
The Body ◽  
Spawning Period ◽  
Tatar Strait ◽  
Todarodes Pacificus ◽  
Squid Abundance ◽  
Northwestern Tatar Strait

Data on commercial catches of japanese flying squid Todarodes pacificus in the northwestern Tatar Strait in 2003–2019 are analyzed. To assess the resours status in the study area, the relative number (individuals per jigger winch per hour) and biomass (kilograms per vessel per day) marks recognized to be the most applicable winch per hour or the catch in kg per vessel per day. The average CPUE value was 35.6 ± 3.6 ind./winch/hour; increasing trend of CPUE is observed (α = 1.5 ± 0.6, r2 = 0.3, p < 0.03). The squid abundance decreased slightly in the last 2 years, with CPUE decreasing to 28 ind./winch/hour in 2019, though the squid biomass was relatively stable (average CPUE 582.0 ± 45.8 kg/vessel/day) — decreased number of caught individuals was compensated by individual body weight increasing. Long-term tendency to the body weight increasing was noted: the average body weight was 205.0 ± 4.0 g in 2004, 256.0 ± 3.5 g in 2012, and 297.0 ± 6.3 g in 2019. Possible climate change influence on the squid population was discussed. Because of warming in the reproductive area of T. pacificus in the southern Japan Sea, SST in the spawning period reached 20–25 оC and exceeded the value optimal for reproduction and larvae development (15–23 оC), so the squid abundance decreased. On the contrary, in the northern Japan Sea (in the Tatar Strait) the warming caused better conditions for the squid feeding: the higher zooplankton biomass in this area was observed under SST 13–18 оC that is reached every year recently. On the other hand, the Tsushima Current intensifying promoted active migrations of T. pacificus to the northwestern Tatar Strait. These factors of climate warming ensure favorable environments for northward migrations of T. pacificus and forming of dense feeding aggregations in the northwestern Tatar Strait that allows to expect good conditions for the squid fishery in this area in the nearest future.

scholarly journals The effect of ice phenology exerted on submerged macrophytes through physicochemical parameters and the phytoplankton abundance

2015 ◽  
Author(s):  
Wojciech Ejankowski ◽  
Tomasz Lenard
Keyword(s):  
Physicochemical Parameters ◽  
Aquatic Vegetation ◽  
Myriophyllum Spicatum ◽  
Ice Cover ◽  
Water Transparency ◽  
Ceratophyllum Demersum ◽  
Total Biomass ◽  
Eutrophic Lakes ◽  
Macrophyte Species ◽  
Tn:Tp Ratio

<p>The physicochemical parameters of water, the concentration of chlorophyll-<em>a</em> and the submerged aquatic vegetation (SAV) were studied to evaluate the effects of different winter seasons on the biomass of macrophytes in shallow eutrophic lakes. We hypothesised that a lack of ice cover or early ice-out can influence the physicochemical parameters of water and thus change the conditions for the development of phytoplankton and SAV. The studies were conducted in four lakes of the Western Polesie region in mid-eastern Poland after mild winters with early ice-out (MW, 2011 and 2014) and after cold winters with late ice-out (CW, 2010, 2012 and 2013). The concentrations of soluble and total nitrogen, chlorophyll-<em>a</em> and the TN:TP ratio in the lakes were considerably higher, whereas the concentration of soluble and total phosphorus and water transparency were significantly lower after the MW compared with after the CW. No differences were found in water temperature, reaction and electrolytic conductivity. Low water turbidity linked with low concentration of chlorophyll-<em>a</em> after the CW resulted in increased water transparency and the total biomass of the SAV. The negative effect of the MW on the macrophyte species was stronger on more sensitive species (<em>Myriophyllum spicatum</em>,<em> Stratiotes aloides</em>) compared with shade tolerant <em>Ceratophyllum demersum</em>. Our findings show that the ice cover phenology affected by climate warming can change the balance between phytoplankton and benthic vegetation in shallow eutrophic lakes, acting as a shift between clear and turbid water states. We speculate that various responses of macrophyte species to changes in the water quality after two winter seasons (CW and MW) could cause alterations in the vegetation biomass, particularly the expansion of shade tolerance and the decline of light-demanding species after a series of mild winters.</p>

Introduction

2018 ◽  
Author(s):  
Caroline Gatrell ◽  
Esther Dermott
Keyword(s):  
Social Research ◽  
Visual Methods ◽  
Policy Makers ◽  
Qualitative And Quantitative ◽  
The Social ◽  
Research Findings ◽  
Research Questions ◽  
Research Relationships ◽  
The Impact

This introductory chapter explains how different research questions and methods can contribute to better understanding of contemporary fathers, fatherhood, and fathering. Given the enhanced methodological diversity and increased sophistication of methods across the social sciences, embracing qualitative and quantitative approaches, traditional (such as interviewing) and contemporary approaches (such as netnography and visual methods), and general ‘handbooks’ offering basic introductions to social research have limited use for advanced researchers and students. The book aims to link detailed concerns about conducting individual projects to wider methodological debates concerning the value of different forms and sources of data, the negotiation of research relationships, and the impact of research findings on participants, policy makers, employers, and a wider public.

scholarly journals Seasonal changes of biological condition and reproductive cycle of hampback shrimp Pandalus hypsinotus (Caridea, Pandalidae) in the Tatar Strait

2021 ◽  
Vol 201 (3) ◽  
pp. 547-560
Author(s):  
D. N. Yuriev ◽  
G. V. Zhukovskaya
Keyword(s):  
Reproductive Cycle ◽  
Japan Sea ◽  
Biological Condition ◽  
Tatar Strait ◽  
Stage Of Development ◽  
Long Time ◽  
Pass Through ◽  
The Individual ◽  
Almost All ◽  
Trawl Catches

Research and commercial trawl catches of humpback shrimp Pandalus hypsinotus from the Tatar Strait (Japan Sea) in 2004–2020 were investigated, with bioanalysis of about 45 thousand specimens. Average timing of group molting, spawning, and eggs laying are determined, terms of gonads and eggs development are estimated. Prespawning and molting of the females occur between January-April, with the peaks in early February and middle February, respectively. All oviparous females have 30–40 days to lay eggs, and molt during 50–55 days; the peak of the eggs laying occurs in late June. The males molt in July-August, afterwards the largest individuals change gender and new intersexes are formed. The males have the second molting in October-December, with the peak in late November. In January, after finish of the males molting, a new annual reproduction cycle starts from the prespawning molting of females. Both vitellogenesis and embryogenesis are observed through the year, though females with developing gonads prevail from August to January (because of a long time span between winter and summer moltings while the egg carrying continued 15 months) but oviparous females — from February to July. The individual reproductive cycle of Pandalus hypsinotus in the Tatar Strait lasts 24 months, with 9 months of vitellogenesis (quick growth of gonads) and 15 months of embryogenesis. During the 2-year reproductive cycle, most of females pass through the following stages: i) gonads development (just after eggs laying) when almost all oviparous females (up to 95 % in May) have green gonads under carapace that corresponds to the stage of development «eggs laid — gonads weakly developed»; ii) summer molting from August when females lose hairs on pleopods and the gonads growth accelerates; iii) respawning in January-March (together with the firstly spawning intersexes, with slight delay of the latter); iv) initial developing of eggs during summer; v) stage of «eyed eggs» from December to March; and vi) eggs laying and molting from late March to late May; then the 2-year reproductive cycle repeats.

scholarly journals Dynamics of stock for yesso scallop Mizuhopecten yessoensis (Jay, 1856) in the northwestern Tatar Strait from the beginning of its fishery to nowadays

2021 ◽  
Vol 201 (3) ◽  
pp. 533-546
Author(s):  
P. A. Dulenina ◽  
A. A. Dulenin
Keyword(s):  
Shell Height ◽  
Mizuhopecten Yessoensis ◽  
Tatar Strait ◽  
Yesso Scallop ◽  
The Mean ◽  
Commercial Value ◽  
Northwestern Tatar Strait ◽  
Commercial Stock

Settlements of yesso scallop Mizuhopecten yessoensis in the northwestern Tatar Strait (within the waters of Khabarovsk Region) are considered on the data of scuba (< 20 m depth) and dredge (> 20 m depth) surveys conducted in 2001–2018. To 2018, only two settlements remain in this area from 9–12 ones in 2010–2014; both remained settlements have no commercial value. Trend to decreasing of the settlements density is shown: the mean density was 3.0 ind./m2 in 2001, 0.20 ind./m2 in 2010, and 0.0005 ind./m2 in 2018. Commercially valuable scallops with the shell height > 120 mm prevailed in the settlements (86–100 %), whereas juveniles were rare or absent (1.6 %, on average) in all years of surveys. CPUE decreased from 200 kg/diver/hour in 2001–2003 to 10 kg/diver/hour in 2018. These changes are obviously reasoned by overexploitation of the population using dredging and scuba gathering. Total commercial stock of yesso scallop dropped to the minimal value in 2018: 200 t, that was in 4.5 times lower than the established limit. Thus, 5 years ban is established for M. yessoensis landing in the area.

scholarly journals THE BUBBLE SEEPAGE AREAS IN THE TATAR STRAIT OF THE JAPAN SEA

2020 ◽  
Author(s):  
А.С. Саломатин
Keyword(s):  
Japan Sea ◽  
Tatar Strait ◽  
The Japan Sea ◽  
Characteristic Features

На основе данных гидроакустических исследований шести морских экспедиций построены карты-схемы положения зон пузырьковой разгрузки метана в Татарском проливе Японского моря у о. Сахалин. Выявлены характерные особенности распределения зон пузырьковой разгрузки метана по глубине, их связи с особенностями морского дна. Оценены размеры этих зон на морском дне. The maps of bubble seepage areas in the Tatar Strait of the Japan Sea based on the data of hydroacoustic studies six marine expeditions were constructed. Characteristic features of distribution of bubble seepage areas on depth and their connection with features of the seabed were revealed. The sizes of these seepage areas on the seabed were estimated.

scholarly journals Sakhalin sturgeon Acipenser mikadoi (Acipenseridae): results of study and proposed measures for conservation of the species

2020 ◽  
Vol 200 (4) ◽  
pp. 791-808
Author(s):  
V. N. Koshelev ◽  
N. V. Kolpakov
Keyword(s):  
Natural Habitat ◽  
Japan Sea ◽  
High Survival ◽  
Artificial Reproduction ◽  
Tatar Strait ◽  
Fish Breeding ◽  
Sakhalin Sturgeon ◽  
Average Fecundity ◽  
Mature Fish ◽  
Acipenser Mikadoi

All available data on sakhalin sturgeon Acipenser mikadoi are summarized. Its historical and modern habitats are described and their significant reduction is noted. Now the species is abundant in the Russian part of its range only — in the Tumnin River, where it is represented in commercial catches by two clearly different groups: large-sized juveniles (FL 43–68 cm) and mature fish (FL 135–169 cm). Juveniles of sakhalin sturgeon migrate during their first years, as their osmoregulatory system forms, to the lower reaches of Tumnin, to the internal estuary, and then to the Datta Bay, the Tatar Strait and the Japan Sea. When returned to the Tumnin, the spawners of sakhalin sturgeon have the length 135–169 cm (n = 29) and weight 15–36 kg. Sex ratio among the caught mature fish is 13.0 : 4 or 3.2 : 1 for females : males, on average. Fecundity of the sturgeon females sampled for artificial reproduction varied from 44.8 to 150.0 thousand eggs, on average 87.3 ± 12.1 . 103 eggs. In total, 17 mature spawners of A.mikadoi were caught in the Tumnin River in 2006–2019 for artificial reproduction (♀ = 13, ♂ = 4), 13 individuals were injected, among them 4/5 of females and 2/3 of males gave high-quality sex products. Producers of this species were distinguished by high survival during manipulations of fish breeding (100 %). Their progeny had low survival, both embryos during incubation and juveniles during rearing; the survival rate for the stage from eggs laid for incubation to juveniles with weight 3.4–7.0 g was 1.85 %. The low survival was supposedly reasoned by combination of unfavorable environmental factors and fish-breeding manipulations. Totally 11,214 juveniles of sakhalin sturgeon with weight from 3.4 to 7.0 g were released into the natural habitat (Tumnin river) in 2007, 2008, 2015, 2017, and 2019. At Anyui sturgeon fish hatchery, the broodstock of sakhalin sturgeon with 274 individuals of 5 ages is created and operated successfully. The male sturgeons in the hatchery mature at the age of 8 years. Here, 11 males of the 2007–2008 year-classes participated in the spawning in 2015–2019. Re-maturation of males was not recorded yet. For the broodstock formation in other fish hatcheries, 200 juveniles of sakhalin sturgeon were transferred to them. To preserve the species, a set of measures is proposed to strengthen its protection and to enhance its artificial reproduction, including the fry releasing into the rivers of the mainland coast, Sakhalin Island, and Japan.

scholarly journals SPECIES COMPOSITION AND DISTRIBUTION OF MACROEPIBENTHOS IN THE COASTAL ZONE OF THE NORTHWESTERN TATAR STRAIT

2019 ◽  
Vol 199 ◽  
pp. 3-18
Author(s):  
P. A. Dulenina ◽  
N. V. Kolpakov
Keyword(s):  
Shelf Zone ◽  
Species Structure ◽  
Depth Range ◽  
Mizuhopecten Yessoensis ◽  
Average Value ◽  
Tatar Strait ◽  
Specific Biomass ◽  
Species Composition And Distribution ◽  
Specific Species ◽  
Northwestern Tatar Strait

Dredgе survey (177 stations) was conducted in the northwestern Tatar Strait (northward from 48° N) at the depths 14–82 m in summer 2018 (from July 21 to August 7). In the dredge catches, 76 species and taxa of benthic invertebrates are recorded, including 42 epibenthic species, mainly Ophiura sarsi, Evasterias echinosoma, Strongylocentrotus pallidus, Paralithodes brevipes, Cucumaria japonica, P. camtschaticus, Mizuhopecten yessoensis, and S. intermedius. The areas of their aggregations are determined. The largest area was occupied by the settlements of polyphagous S. pallidus (5100 km22 at the depths 30–60 m). Specific biomass of epibenthos is calculated, its average value within the surveyed area was 21.5 ± 2.0 g/m2. Depth ranges of the species domination are defined. The dominant species changed with latitude: in the southern part of the survey, Paralithodes camtschaticus dominated with the biomass of 5.1 ± 4.4 g/m2 in the upper 20 m layer (48–49° N), replaced at the depth of 20–30 m by P. brevipes (22.2 ± 14.2 g/m2 between 48–49° N) or C. japonica (28.2 ± 3.0 g/m2 between 49–50° N), both species changed deeper to S. pallidus (4.3 ± 1.1 g/m2); in the northern part of the survey (50–51° N), S. intermedius dominated in the upper 30 m layer with the biomass of 14.7 ± 9.5 g/m2, Mizuhopecten yessoensis (9.7 ± 6.2 g/m2 ) and Evasterias echinosoma (5.1 ± 1,0 g/m2 ) prevailed in the depth range of 30–40 m and were replaced by S. pallidus (18.0 ± 9.5 g/m2) below 50 m; in the northernmost shallow tip of the Strait, Ophiura sarsi dominated absolutely with the biomass of 13.0 ± 1.1 g/m2) in the whole depth range down to 30 m. The greatest species richness and abundance of epibenthos were observed at the depths not exceeding 40 m. Statistically significant decreasing of quantitative parameters of the epibenthos with the depth is observed because of the bottom temperature and topical diversity declination with depth. However, environmental conditions have no significant impact on latitudinal distribution of abundance, wealth and species diversity of the epifauna in the surveyed area. The grouping of epibenthos with specific species structure that could be classified as the circumlittoral one is defined in the upper shelf zone in the northernmost area with the depth < 30 m (somewhere < 40 m).

Qualitative and quantitative composition of phytoplankton in the Golden Horn Bay, Japan Sea

2018 ◽  
Vol 194 ◽  
pp. 167-174
Author(s):  
I. V. Stonik
Keyword(s):  
Phytoplankton Biomass ◽  
Japan Sea ◽  
Organic Pollution ◽  
Average Density ◽  
Quantitative Composition ◽  
Iodine Solution ◽  
Qualitative And Quantitative ◽  
Golden Horn ◽  
Average Biomass ◽  
Phytoplankton Cells

Qualitative and quantitative composition of phytoplankton in the Golden Horn Bay (Japan Sea) was investigated in the period from October 2009 to October 2010. The water samples of 1 L volume were taken with Molchanov bottle at the 36th Berth where ship-repairing yards were located and naval and commercial ships were moored. The samples were fixed in Utermӧhl iodine solution and phytoplankton cells were concentrated by precipitation or by reverse fil­tration, then the concentrated samples were processed under microscope. In total, 135 species and intraspecific taxa of microalgae were detected, which belonged to 7 divisions. Average density of phytoplankton cells varied from 1.9 . 103 to 610.3 . 103 cells/L, its average biomass varied from 0.02 to 11.70 g/m3. Four peaks of the phytoplankton cells density were registered: in summer, spring, winter and fall (in descending order), with the highest density in June, but only one peak of the phytoplankton biomass was observed in February. The highest density (up to 1 . 106 cells/L) was formed by euglenophytes that was similar to the neighboring Amur Bay and obviously indicated organic pollution of the Golden Horn Bay waters. Comparing with results of previous observations in the 1990s and 2000s, the species diversity of dominant diatoms and euglenophytes has increased recently. These species are known as indicators of eutrophic waters and/or organic pollution.  

Sign in / Sign up

Export Citation Format

Share Document