A new approach to the problem of origin and dispersal of genus Salvelinus is proposed, based on analysis of their ecology and reproductive biology forming in the process of climatic and geological evolution of the Earth. There was concluded that the ancestor of the char species formed from one of the coldest populations of phyletic line Parasalmo clarki — Salmo trutta that occurred in an isolated region of the East Arctic at the beginning of the Pliocene. With further cooling of climate in the East Arctic, the chars adopted consistently to colder living conditions, and the stages of these adaptations were fixed during isolation of the ancestral forms outside the region. The most ancient char species is Salvelinus leucomаenis evolved about 4 million years ago. Most other species of this genus were formed at the end of the Pliocene during the first glaciation of the Northern Hemisphere. Cristivomer namaycush is considered as the species belonged to subfamily Huchoninae, and the phylogenetic branch of Salvethymus svetovidovi as that formed independently from the chars in the Pacific Ocean. Evolution of salmon fishes developed since the late Miocene toward adaptation to progressive cooling of climate, so the chars of genus Salvelinus and Cristivomer namaycush acquired convergent similarity as the most cold-water representatives of the phyletic lines Salmoninae and Huchoninae.

Sublittoral vegetation communities in the Russian Far Eastern Seas are still poorly and unsystematically studied. Scopes of the communities described by different authors are different or unclearly defined. Any general methodological framework that would allow systematizing their composition has not yet been proposed. The concept of adaptive zone (AZ) can be such methodological basis for systematizing diverse descriptions. AZ is understood as a vegetation cover area in which the living conditions of a single species are so favorable that it dominates in abundance over others and forms communities with its own dominance. Mosaic of these communities can be described as a vegetation association. Distribution of sublittoral vegetation communities in the Far Easters Seas is inventoried and analyzed using this approach on the base of information on dominant species of sublittoral vegetation in all available scientific literature where both quantitative data and verbal notes on species domination in certain areas are selected. In total, 67 associations are identified in 13 areas of the Far Eastern Seas. One third of the associations are narrowly distributed in a single region, a half of them are moderately distributed in 3–5 regions, the others are widespread in 7–9 regions. High-boreal areas are cenotically poor (5–11 associations in each), low-boreal areas are cenotically rich (23–31 associations in each). Within the regions, the vegetation composition is distinguished by high similarity in the Japan Sea (at least 62 %) and the northern Okhotsk Sea (at least 73 %). Signifi-cant thermo-cenotic (α = 1.7 ± 0.3, R² = 0.71, p = 0.0006) and flora-cenotic (α = 0.14 ± 0.06, R² = 0.56, p = 0.05) gradients are noted as the indices of natural increasing of the associations quantity from north to south that corresponds to the Humboldt-Wallace rule and represents its phytocenotic aspect. The ratio in the number of communities belonging to different systematic groups can characterize thermotropism of vegetation in vast or local areas.

Results of monitoring on the pink salmon spawning in the rivers of Aniva Bay (southern Sakhalin Island) in 1975–2004 are presented, including dynamics of the fish run to the coast and the number of spawners on the spawning grounds, biological parameters of the spawners, and quantitative accounts of the juveniles migrated downstream the monitored rivers. Based on these data, the total number of parent fish, juveniles, and returning adults are estimated for each year-class and the reproduction efficiency of pink salmon in the freshwater and marine periods of their life are calculated. Dynamics of pink salmon abundance in the Aniva Bay and dominance of the generative line of odd years were mostly determined by factors acting during the marine period of life, that’s why the number of returned adults depended more on the number of juveniles than on the number of producers on the spawning grounds.

Dynamics of catches and biological parameters are analyzed for pink salmon during their approaches to the Kuril Bay (Iturup Island, Kuril Islands) in 2015, as the body length, female fecundity, and inter-sclerite distance in the first annual growth zone of scales. These parameters were compared between the fish caught at the outer boundary of the bay and at the mouths of spawning rivers. The scale growth patterns atypical for local herds of pink salmon and heightened fertility of females were observed in the catches obtained in the external part of the bay; these fish migrated obviously to another area of their reproduction.

Age of masu salmon in catches of RV Professor Kaganovsky trawl survey in the Okhotsk Sea in autumn 2024 is estimated by scales and otoliths. The scale samples were collected from 85 specimens of masu salmon with body length from 240 to 456 mm (weight 159–1425 g) and the otoliths were taken from 70 of these specimens. The percentage of fish at age 1.0+ and 2.0+ was 76:24 for the estimations by scales (N = 76) and 66:34 for the estimations by otoliths (N = 68). All examined specimens were at age R.0+; the masu salmon overwintered at sea (age R.1+) were not observed. Images of the scales and otoliths of fish at ages 1.0+ and 2.0+ are provided with explanations. Biological data on the examined specimens are presented with the coordinates of their capture and results of the age estimation. Spatial distribution of masu salmon in the Okhotsk Sea in autumn of 2024 is discussed on the data of joint survey of RV Professor Kaganovsky and RV TINRO.

Results of fishery on pink salmon Oncorhynchus gorbuscha of even year-classes in the Primorye fishing subzone (within the boundaries of Primorye and Khabarovsk Regions) in 2022 and 2024 are analyzed on the background of annual catch dynamics. Significant differences between the years is noted both in distribution of the catch between regions and in timing of the mass run. The main factor that determined the timing and direction of the run for pink salmon was the approaching of Tsushima Current warm jets to the coast that provided optimal conditions for the spawning migration. Meanwhile, the Tsushima Current was active in both considered years driven by prevailing southerly winds supported with atmosphere pressure gradient between the Far-Eastern Low over the mainland and strengthened western ridge of the Hawaiian High that also caused warm air invasion to the northern Japan Sea. Such environmental conditions are generally favorable for migration of pink salmon, but exact timing, spacing and strength of their runs are determined by mesoscale patterns of water dynamics.

Results of microbiological tests of water and bottom sediments conducted at the sites of natural and artificial reproduction of scallop Mizuhopecten yessoensis in the Aniva Bay from May to October 2024 are presented. The total abundance of bacterioplankton at the sea surface ranged in 0.50–2.14.10⁶ cells/mL, at the bottom — in 0.80–1.24.10⁶ cells/mL, and their biomasses were 37.13–220.42 and 69.99–161.12 mg/m³, respectively. These values corresponded to mesotrophic-eutrophic class of water. The abundance of saprotrophic bacteria in the surface layer varied seasonally from 10² to 10⁵ cells/mL. Such seasonal changes were not registered in the bottom layer and bottom sediments where their abundance varied within the orders of 10⁴–10⁵ cells/mL. No species of sanitary and indicative microflora were detected that was a sign of absent anthropogenic influence. Еtiologically significant Vibrio parahaemolyticus bacteria were found in water and bottom sediments which are the pathogens of food poisoning for humans.

Published methods of unmanned counting of pacific salmon allow to obtain high-quality photographic materials, but their processing is a rather hard labor. Practice of using the artificial intelligence methods, in particular deep learning models (otherwise — artificial neural networks), for this purpose is still insufficient, preliminary and concerns the counts of post-spawn chum salmon only. In this study, a deep learning model was created capable for effective automatic species-specific detection of chum and coho salmon spawners and post-spawn chum salmon in multi-species aggregations using enumerated data of unmanned surveys. This neural network is based on wide training materials and is able to process simultaneously images with several classes of objects and identify all of them. Detailed and reproducible technical description of the preparation, quality control, and operation with the deep learning model for pacific salmon is presented for a desktop GIS environment. Various factors affecting quality of the neural network are described, and recommendations for improving its work are given. Quality indicators of the model should be considered in the context of visual characteristics of target objects in processed photographic materials, which can vary significantly. Quality of the neural network output can be improved by using functionality of geoinformation software. Recommendations are given for optimizing the model development using the tools of photogrammetric and geoinformation software. Scheme for recalculating the neural network output based on processed photographic materials is proposed to obtain a corrected estimate of the total number of objects in the surveyed water area.

A new methodic approach is proposed that allows to formalize and refine the expert assessments of the basic parameters of fish population dynamics obtained by indirect methods, such as reproduction and mortality rates, and to compensate partially gaps in fishery statistics. It is based on well-known results of Tyurin [1972], Richter and Yefanov [1977], and Zykov and Slepokurov [1982] concerning the total mortality rate dependence on fishing pressure in exploited fish populations. The mortality rate can be used as a criterion for effectiveness of fishery regulation measures.