scholarly journals Some features of the pale sea urchin (Strongylocentrotus pallidus) biology in Peter the Great Bay (Japan Sea)

2017 ◽  
Vol 188 (1) ◽  
pp. 140-154
Author(s):  
Maria O. Chalienko ◽  
Marianna V. Kalinina
Keyword(s):  
Continental Slope ◽  
Sea Urchin ◽  
Size Structure ◽  
Sea Urchins ◽  
Peter The Great Bay ◽  
Maturity Stage ◽  
Shelf Area ◽  
Peter The Great ◽  
Great Bay ◽  
Average Size

Population of pale sea urchin Strongylocentrotus pallidus in Peter the Great Bay is investigated. The samples for its size structure and distribution were collected at the depth from 5 to 700 m in July 2013, 2014 and in April 2015 and the samples for the state of gonads, intestines and age structure - at the depths of 41, 69, 280, 346, and 670 m in early April 2015. The size structure at different depths is significantly different: the large individuals with average size of 70.0 mm (portion of commercial ones 98 %) occupy mainly the middle shelf area with the depths of 55-100 m, deeper at the depths of 100-200 m the portion of commercial urchins is lower (67 % in 2014 and 92 % in 2015), and the continental slope (depth > 200 m) is occupied by mainly (77-96 %) non-commercial individuals with average size of 35.5 mm. Age of sea urchins was determined by the growth zones on plates of their shells processed by Jensen method and varied from 3 to 12 years. The growth rate of sea urchins from the shelf areas was approximately in 1.5 times higher as compared with those from the continental slope, primarily due to different conditions of feeding. The gonads cellular composition was defined for the samples of 50 cells per female. The cells were differentiated in the categories of oocytes proliferation, oocytes differentiation, and mature eggs, and the gonad maturity stage was determined by domination of these categories, taking into accounts the S. pallidus reproductive cycle. In spring, the sea urchins from the shelf areas (depths of 41 and 69 m) were generally more mature as compared with those from the continental slope (depths of 280 and 346 m). However, correlation between the gonadal index and depth of habitat was not significant because the mature females were sampled in any depth. Composition of intestinal content and food components were determined visually, looking the bolus under binocular microscope. The sea urchins intestines were mostly filled with detritus at the depth of 41 m, sponges (Suberites sp.) at the depth of 69 m (70 % of cases), and unedible substances as silt and sand at the depth of 280, 346 and 670 m, minor fractions were the algal litter, remains of crustaceans, and detritus.

scholarly journals Seasonal and inter-annual dynamics of biological parameters for mysid Paracanthomysis shikhotaniensis in Peter the Great Bay (Japan Sea)

2020 ◽  
Vol 200 (4) ◽  
pp. 907-921
Author(s):  
L. G. Sedova ◽  
L. L. Budnikova
Keyword(s):  
Body Length ◽  
Size Structure ◽  
Peter The Great Bay ◽  
Late Summer ◽  
Japan Sea ◽  
Weather Conditions ◽  
Early Summer ◽  
Sex Structure ◽  
Peter The Great ◽  
Great Bay

Size and sex structure of the mysid Paracanthomysis shikhotaniensis aggregations in Peter the Great Bay (Japan Sea) is considered. The samples were collected at the depth of 0.5–2.0 m at Reineke Island in May-October of 2014–2018. All sampled mysids (1601 ind.) were measured under binocular microscope with accuracy of 0.1 mm, weighted by torsion scales with accuracy of 1 mg, and separated to males, females and juveniles. The females were differentiated by 5 stages of their development: 1) immature females with oostegetic rudiments; 2) oviparous females; 3) females with embryos in the marsupia bags without stalk-eyes with black pigment; 4) females with embryos in marsupia bags with black eyes; and 5) spawned females with empty marsupii. Their body length varied from 5.0 to 27.8 mm, being much larger in spring and early summer than in late summer and autumn. Juveniles were absent in spring, but abundant in July-October. Females were larger than males, their body length varied from 9.0 to 27.8 mm, whereas the length of males — from 8.3 to 19.0 mm. Seasonal variations of the size structure were similar in different years, with small deflections due to changes of water temperature and weather conditions. In contrast, sex structure of the mysid aggregations had significant interannual differences. The females to males ratio was almost stable from June to September (females prevailed), but changed to males domination in October. Spawning of P. shikhotaniensis was extended in time because of several generations spawned, that was confirmed by permanent occurrence of females with embryos at different stages of development.

The large-scale vegetation maps of the western coast of Peter the Great Bay (Far East, the Sea of Japan)

2000 ◽  
pp. 50-61 ◽  
Author(s):  
S. V. Osipov ◽  
V. P. Verkholat
Keyword(s):  
Vegetation Cover ◽  
Large Scale ◽  
Far East ◽  
Peter The Great Bay ◽  
The Sea Of Japan ◽  
Western Coast ◽  
Spatial Unit ◽  
Peter The Great ◽  
Great Bay ◽  
River Valleys

Two territories on the western coast of Peter the Great Bay were mapped in the large scale. The geobotanical mapping means revealing and displaying the essential regularities of vegetation cover. Both the spatial and temporal regularities of vegetation under natural and anthropogenic influences are well pronounced in the territory under consideration. The concept of the vegetation spatial unit (vegetation complexes) was applied as a basis for mapping. The maps and their legend were worked out as a system of vegetation combination types (vegetation combination is a spatial unit of the supracoenotic level). Such categories, as vegetation of tops and slopes, lowlands and river valleys, sea coasts reflect maximal contrasts in vegetation cover, so they are the highest level divisions of the map legend. Types of succession series and stages of series are developed for construction of the second and third levels of the legend. Communities, similar in ecotope, total species composition, saplings and some other characteristics, are referred to one type of series. 5 types of series have been distinguished: dry, fresh, moist, very moist, wet. The main factor of dynamics in considered territory is fire and the series are mainly pyrogeneous. Series are presented as sequences of vegetation stages. The vegetation stages for tops and slopes are: closed low forest — open low woodland — shrub thicket with saplings — meadow with saplings, for lowlands and river valleys they are: open low woodland — thicket of saplings — meadow or mire with saplings.

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