scholarly journals On the intraspecific competition of yellowfin sole Limanda aspera (Pallas, [1814]) (Pleuronectidae) in the eastern part of the Sea of Okhotsk

Author(s):  
Yu. P. Dyakov

Based on the longterm observations for 1963–2019, the article provides an assessment of the yellowfin sole generation mortality dynamics depending initial abundance and population dynamics in view of abundance and biomass. Individual growth and matiration rates were evaluated in generations with different initial abundance and in different states of population dynamics. Results indicated about intraspecific competition in yellowfin sole in the eastern part of the Sea of Okhotsk, expressed in specifics of the dynamics of stock abundance, growth and maturation. Forming generation stock abundance in early and later ages has different character. The more exceeding number of parental eggs spawned, the more generation abundance of yearlings getting exactly compensated by mortality (complete compensation). Older generations demonstrate the phenomen of “overcompensation”, when mortality of generations appeared in the years of higher egg production exceeds fertility. In the period of population growth and stabilization at a high level the period of the Yellowfin sole abundance fluctuation cycle gets shorter and the amplitude – smaller. Effects of intraspecific competition on the growth of individuals are revealed. Negative effects of the competition authentically revealed in elder age groups were not observed in younger age groups. An increase of the Yellowfin sole abundance brings negative effects on maturation rate of males with almost no such effects on females. To the greatest extent such effects can be seen in young age groups, at the beginning and middle stage of maturation.

2006 ◽  
Vol 3 (4) ◽  
pp. 1157-1202
Author(s):  
L. Dzierzbicka-Głowacka ◽  
L. Bielecka ◽  
S. Mudrak

Abstract. A population dynamics model for copepods is presented describing a seasonal dynamics of Pseudocalanus minutus elongatus and Acartia spp. in the southern Baltic Sea (Gdansk Deep). The copepod model was coupled with an one-dimensional physical and biological upper layer model for nutrients (total inorganic nitrogen, phosphate), phytoplankton, microzooplankton and an early juvenile of herring as predator. In this model, mesozooplankton (herbivorous copepods) has been introduced as animals having definite patterns of growth in successive stages, reproduction and mortality. The populations are represented by 6 cohorts in different developmental stages, thus assuming, that recruitment of the next generation occurs after a fixed period of adult life. The copepod model links trophic processes and population dynamics, and simulates individual growth within cohorts and the changes in biomass between cohorts. The simulations of annual cycles of copepods contain one complete generation of Pseudocalanus and two generations of Acartia in the whole column water, and indicate the importance of growth of older stages of 6 cohorts each species to total population biomass. The peaks of copepods biomass, main, at the turn of June and July for Pseudocalanus and smaller, in July for Acartia, lag that phytoplankton by ca. two mouths due to growth of cohorts in successive stages and egg production by females. The numerical results show that the investigated species could not be the main factor limiting the spring phytoplankton bloom in the Gdansk Deep, because the initial development was slow for Acartia and faster for Pseudocalanus, but main development formed after the bloom, in both cases. However, the simulated microzooplankton biomass was enough high to conclude, in our opinion, that, in this case, it was major cause limiting phytoplankton bloom. Model presented here is a next step in understanding how the population dynamics of a dominant species in the southern Baltic Sea interact with the environment.


Author(s):  
N.G. Klochkova ◽  
◽  
A.V. Klimova ◽  
T.A. Klochkova ◽  
◽  
...  

Western Kamchatka is still poorly studied in floristic and fishing aspects and there is no accurate understand-ing on the boundaries of different kelp species distribution in the area. During the 2020 field study in the coastal area located from Cape Ambon to the mouth of Utholok river, including the area proximate to Ptichiy Island, we found 5 kelp species, including Phyllariella ochotensis, Pseudolessonia laminarioides, Laminaria inclinatorhiza, Saccharina latissima, and Alaria esculenta sensu lato. The first 3 species are endemic to the mainland coast of the Sea of Okhotsk. A special search off the coast of southwestern Kamchatka for another Okhotsk endemic species, Laminaria appressirhiza, showed that it was absent. A representative of the Ber-ing Sea kelp flora Hedophyllum bongardianum does not occur on western Kamchatka north of 51°N. The morphometric characteristics of plants belonging to different age groups and morphological features typical for Western Kamchatka’s populations of these species are discussed. Additionally, the molecular phylogeny of L. appressirhiza and H. bongardianum collected from the Sea of Okhotsk are discussed. As shown, the first species belongs to the genus Laminaria. From a commercial point of view, this coastal area was estimated as unpromising for the organization of kelp collection by a traditional manual method.


Fisheries ◽  
2020 ◽  
Vol 2020 (6) ◽  
pp. 108-110
Author(s):  
Viacheslav Zharnikov ◽  
Andrey Smirnov

The growth of various size groups of mussels in the Veselaya Bay of the tauyskaya Bay, grown in mono - and polyculture in suspended cages in the sea, was analyzed. The maximum growth was observed in mussels of the size group 10-20 mm at the age of 2 years. Shellfish grew more slowly at the age of 3-5 years. The growth rate of mollusks of all size groups in the polyculture was higher than in the monoculture. The percentage of elimination of mussels of all age groups in the polyculture was significantly lower. The forecast of growth of mussels of various size groups in poly - and monoculture in suspended cages in the first, second and third growth seasons in Veselaya Bay is made. The efficiency of cultivation of mussels in the Northern part of the sea of Okhotsk together with other edible mollusks: makoma and Miya is shown.


2006 ◽  
Vol 3 (4) ◽  
pp. 635-650 ◽  
Author(s):  
L. Dzierzbicka-Głowacka ◽  
L. Bielecka ◽  
S. Mudrak

Abstract. A population dynamics model for copepods is presented, describing the seasonal dynamics of Pseudocalanus minutus elongatus and Acartia spp. in the southern Baltic Sea (Gdańsk Deep). The copepod model was coupled with a one-dimensional physical and biological upper layer model for nutrients (total inorganic nitrogen, phosphate), phytoplankton, microzooplankton, and an early juvenile of herring as a predator. In this model, mesozooplankton (herbivorous copepods) has been introduced as an animal having definite patterns of growth in successive stages, reproduction and mortality. The populations are represented by 6 cohorts in different developmental stages, thus assuming that recruitment of the next generation occurs after a fixed period of adult life. The copepod model links trophic processes and population dynamics, and simulates individual growth within cohorts and the changes in biomass between cohorts. The simulations of annual cycles of copepods contain one complete generation of Pseudocalanus and two generations of Acartia in the whole column water, and indicate the importance of growth in the older stages of 6 cohorts of each species, to arrive at a total population biomass. The peaks of copepods' biomass are larger at the turn of June and July for Pseudocalanus and smaller in July for Acartia, lagging that of phytoplankton by ca. two mouths, due to the growth of cohorts in successive stages and egg production by females. The numerical results show that the investigated species could not be the main factor limiting the spring phytoplankton bloom in the Gdańsk Deep, because the initial development was slow for Acartia and faster for Pseudocalanus, but the main development formed after the bloom, in both cases. The phytoplankton bloom is very important in the diet of the adults of the copepods, but it is not particularly important for the youngest part of new generation (early nauplii). However, the simulated microzooplankton biomass was enough high to conclude, in our opinion, that, in this case, it was a major cause in limiting phytoplankton bloom. The model presented here is a next step in understanding how the population dynamics of a dominant species in the southern Baltic Sea interact with the environment.


2018 ◽  
Vol 52 (1) ◽  
pp. 63-73
Author(s):  
N. V. Evseeva

The revision of the herbarium material, collected in the northern part of the Sea of Okhotsk in 1965–1966 and stored in VNIRO, allowed to expand the taxonomic list of macrophyte algae of the coastal zone of this area. The locations of discovery of 24 previously unmentioned species are described. Myrionema balticum, Ulvella repens, Syncoryne reinkei, Acrochaetium arcuatum were found in the Sea of Okhotsk for the first time. Most species new for the Sea of Okhotsk is represented by epiphytes of the family Ulvellaceae (Chlorophyta). The final taxonomic list of this region, including literature data, consists of 169 species.


Author(s):  
Alexandra Romanova ◽  
Alexandra Romanova ◽  
Vladimir Anin ◽  
Vladimir Anin ◽  
Sergey Pletnev ◽  
...  

80 sediment stations collected along the meridian transect across the Sea of Okhotsk were studied in order to reveal patterns of dissolution based on planktonic foraminifera. The degree of calcite dissolution intensity from planktonic foraminifera determined by different indices (degree of fragmentation, presence of susceptible to dissolution species, benthos/ plankton ratio). The highest degree of dissolution evidenced by a large number of shell fragments and corroding walls were found in sediments from the area of the Kuril Islands. The most revealing measure of probable dissolution of foraminiferal shells in the central part of the sea is a low number and lack of thin-walled species. The effects of dissolution on foraminiferal shells were studied for dominated species Neogloboquadrina pachyderma sin and Globigerina bulloides using a scanning electron microscope. The results are important for understanding processes of sedimentation, the paleo-oceanologial reconstructions and for obtaining reliable results in isotope analyzes.


2016 ◽  
Vol 25 (1) ◽  
pp. 13-22
Author(s):  
N.A. Sedova ◽  
S.S. Grigoriev

For the first time the morphology of the decapodid stage of Neocrangon communis is described in detail. The decapodid can be distinguished from those of the genera Argis, Crangon, and Mesocrangon by the morphology of their telson, antennae, antennulae, and carapace. The main distinguishing features of the decapodid of N. communis were two spines on medial line of the carapace, a short rostrum, relatively wide scaphocerite, characteristic shape and length of the terminal setae on the telson. Drawings of general view and some limbs are presented.


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