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).

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.

Species composition and distribution of marine macro algae at Co To and Thanh Lan archipelago

2020 ◽  
Vol 20 (3) ◽  
pp. 267-276
Author(s):  
Dam Duc Tien ◽  
Nguyen Thi Mai Anh ◽  
Linh Manh Nguyen ◽  
Pham Thu Hue ◽  
Lawrence Liao
Keyword(s):  
Species Composition ◽  
Littoral Zone ◽  
Marine Algae ◽  
Similarity Coefficient ◽  
Algal Flora ◽  
Average Value ◽  
Site Number ◽  
Species Composition And Distribution ◽  
Total Species ◽  
Macro Algae

This paper exhibites species composition and distribution of marine seaweed at 10 sites of Co To and Thanh Lan islands in May 2019. The studies record 76 species of marine algae in the area, belonging to four divisions: Cyanophytes, Rhodophytes, Ochrophytes and Chlorophytes. Among them, five species are classified into Cyanophytes (comprising 6.6% of total species); thirty-four species into Rhodophytes (44.7%); twenty-one species into Ochrophytes/Phaeophytes (27.6%) and sixteen species into Chlorophytes (21.1%). The species composition of marine seaweeds in Co To and Thanh Lan shows significant differences as follows: 22 species (sites number 4 and 10) to 58 species (site number 2) and the average value is 38.7 species per site. Sørensen similarity coefficient fluctuates from 0.33 (sites number 5 and 10) to 0.84 (sites number 1 and 3) and the average value is 0.53. The current investigations show that four species of twenty-one species are collected in the littoral zone and forty-two species in the sub-littoral zone (in which there are thirteen species distributed in both littoral zone and sub-littoral zone). The algal flora in Co To and Thanh Lan is characterized by subtropics.

Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries

2008 ◽  
Keyword(s):  
Stock Assessment ◽  
Distribution Patterns ◽  
Common Species ◽  
Depth Range ◽  
The North ◽  
The World ◽  
Mid Atlantic Ridge ◽  
The North Atlantic ◽  
Species Composition And Distribution ◽  
Trawl Catches

<em>Abstract.—</em>The Mid-Atlantic Ridge of the North Atlantic is inhabited by at least 16 macrourid species in 9 genera. The species composition and distribution patterns are analysed based on bottom trawl catches in the depth range 985 to 3461m conducted on the 2004 MAR-ECO expedition between the Azores and the southern Reykjanes Ridge. Some of the species, e.g. roundnose grenadier <em>Coryphaenoides rupestris</em>, <em>C. brevibarbis </em>and abyssal grenadier <em>C. armatus, </em>rank among the most abundant demersal fishes on the ridge or in the deep axial valleys or fracture zones, while others are uncommon or rare. While a few species have apparently restricted northerly or southerly distributions, most are widespread. Among common species that occur along the entire ridge section investigated, there are indications of structuring by depth of occurrence.

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.

Ecological change in Great Lakes communities — a matter of perspective

2008 ◽  
Vol 65 (1) ◽  
pp. 1-9 ◽  
Author(s):  
W Gary Sprules
Keyword(s):  
Great Lakes ◽  
Food Webs ◽  
Emergent Properties ◽  
Size Spectrum ◽  
Species Structure ◽  
Ecological Change ◽  
Size Spectra ◽  
Rate Processes ◽  
African Rift ◽  
Specific Species

Enormous change in food webs of the Laurentian Great Lakes has been documented from the early 1970s to the 1990s. Variation in abundances of species at all levels in these food webs has been attributed to a variety of causes, including nutrient abatement, invasive species, fishing practices, and climate change. However, this impression of great change is not obvious if food webs are examined from the different perspective of the biomass size spectrum. Despite large shifts in the species structure of zooplankton communities in Lakes Erie and Ontario from 1991 to 1997, zooplankton size spectra have not changed. Furthermore, size spectra for complete food webs of Lake Ontario (Laurentian Great Lake) and Lake Malawi (African Rift Valley Lake) are statistically indistinguishable despite enormous contrast in the geological age and fauna of the two lakes. I conclude that constraints on bioenergetic rate processes and physiological and ecological similarities of like-sized organisms at various hierarchical levels of organization lead to regular and repeatedly observed emergent properties of aquatic ecosystems that are independent of specific species.

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 Species Compositiom and Distribution of Seaweeds at Thi Nai Lagoon, Binh Dinh Province

2017 ◽  
Vol 33 (4) ◽  
Author(s):  
Dam Duc Tien
Keyword(s):  
Species Composition ◽  
Littoral Zone ◽  
Algal Flora ◽  
Average Value ◽  
Marine Algal ◽  
Number Species ◽  
Species Composition And Distribution ◽  
Total Species ◽  
Dry And Rainy Seasons ◽  
Eleven Species

This paper presents results on species composition and distribution of seaweeds at Nai lagoon, Ninh Thua province from 2013 until 2014 at 12 sites was showed that, at Nai lagoon area we was recording 43 species of marine seaweeds, they are belonging to four divisions, as: Cyanophytes, Rhodophytes, Phaeophytes and Chlorophytes. Among them, eight species are classified in Cyanophytes (comprising 18.6% of total species); eleven species in Rhodophytes (25.6%); four species in Phaeophytes (9.3%) and twenty two species in Chlorophytes (46,5%). The species composition of marine seaweeds from Thi Nai lagoon show significant differences in the species composition as follows: 8 species (side number 4, 13 and 18) to 21 (side number 10) and average value is 12.2 species per side. The number species at dry season is 40 and rainy season is 30 (there are 30 species in of boots dry and rainy seasons) Coefficient homogeneous is oscillating from 0.10 (side number 4 and 5) to 0.66 (5 and 7). The current investigations show that 39 species of 43 species were collected in the littoral zone and 35 species in sub-littoral zone (31 species are distributing in both the tide and the sub tide). Marine algal flora in Thi Nai lagoon is represented by tropical elements as defined by Cheney.

The ratio of the travel times for S and P at distances less than 10°

1980 ◽  
Vol 70 (3) ◽  
pp. 823-829
Author(s):  
A. L. Hales ◽  
K. J. Muirhead
Keyword(s):  
Upper Mantle ◽  
Depth Range ◽  
Travel Times ◽  
Laboratory Measurements ◽  
Mantle Minerals ◽  
Distance Range ◽  
Average Value ◽  
The Times

abstract The ratios of the S and P travel times, Ts/ Tp, observed at central Australian stations from Banda Sea earthquakes with depths between 100 and 200 km are less than the corresponding ratios for surface explosions in the same distance range. This result is surprising and inconsistent with the increase in the Vp/ Vs ratio with depth inferred from laboratory measurements on upper mantle minerals. Studies from several continental regions, including Japan, and oceanic regions, show similar low values. Possible reasons for the inconsistency are discussed. Studies of three well-observed earthquakes in the Hokkaido region lead to the conclusion that the depths of earthquakes in the 60 to 200 km depth range are systematically underestimated by ISC and that there is an associated error in the times of origin of about 3 sec. Using corrected origin times, the average value of the Ts/ Tp ratio over the distance range 0° to 8° is about 1.785.

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