VNIRO scientists are assessing the state of invertebrate and algae reserves

 

The population of the coastal zone of Sakhalin Island is characterized by a significant diversity of species, their mosaic and uneven distribution in space, as well as a complex composition of communities. These features of the coastal biota suggest the use of various research methods, including the use of diving equipment.

 

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Divers establish the lower boundary of the distribution of invertebrates and the algal belt, determine the depth and distance to the shore. At each station, they determine the nature of the soil, transparency, water temperature, invertebrate population density, and projective seaweed cover (%) and the proportion of common species in them, and also collect all types of seaweed and invertebrates within sight to determine the species composition of the benthos in the area. Based on the data obtained on the size of catches, they construct maps of the distribution of species and calculate their stock (biomass or abundance).

 

A diving survey of the sea (primorsky) scallop was successfully conducted in the Alexander Bay.

 

The main objective of the study was to obtain information on the spatial distribution, abundance, and biomass of the primorsky scallop (Mizuhopecten yessoensis).

 

The work was carried out at depths from 10 to 20 meters. 117 diving stations were set up at 30 sections, which made it possible to estimate the density of the mollusk population in the surveyed area of the water area and provided a detailed study of the biological state of the scallop population.

 

During the work, 450 specimens of the Japanese scallop were taken for a full biological analysis and 650 specimens for mass measurement. As a result of the analysis, the age groups and spawning state of the population were determined, and the average size and weight characteristics of the mollusks were obtained.

 

A census and morphometric analysis of the accompanying species of aquatic organisms were carried out, the bulk of which were the starfish Asterias amurensis, Patiria pectinifera, Distolasterias nipon, Aphelasterias japonica, etc. Neptunea bulbacea, Neptunea arthritica, Strongylocentrotus intermedius, Cucumaria frondosa japonica were also found in the catches. As a result of the work, the spatial distribution of the Japanese scallop, its density and biomass were determined, and the biological state of the population was assessed.

 

A diving survey of the sea urchin and algae was carried out off the southeastern coast of Sakhalin.

 

The area of the work is the water area off the southeastern coast of Sakhalin from Cape Cornelia to Cape Svobodny (East Sakhalin subzone). A 76 km long section was surveyed. A large volume of field work was carried out: 208 diving stations, 450 specimens of kelp and 2000 specimens of gray sea urchin were analyzed.

 

Commercial aggregations of gray sea urchins were found in the surveyed area. At the same time, large aggregations of alaria and other algae, which are commercial species, were found.

 

During the research work carried out in the coastal zone of southeastern Sakhalin in July 2025, new data were obtained on the spatial distribution of gray sea urchin and brown algae. A preliminary quantitative assessment of the state of raw material resources was given. The material on the size-mass structure of commercial hydrobionts is presented for the subsequent development of recommendations on the rational management of the fishery of these objects.

 

Press service of VNIRO