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Vol 65, No 1 (2025)
Articles
New data on the ichthyofauna composition in the White Sea
Abstract
The paper presents the up-to-date information on the composition of the White Sea ichthyofauna, updated from literature sources and the results of regular studies conducted by the Russian Federal Research Institute of Fisheries and Oceanography, Northern Branch in 1980−2023. During more than 40 years of trawl and coastal surveys, 64 species (subspecies) of pisciformes and fishes have been recorded in catches. Five species are listed for the White Sea for the first time: the freshwater species, the silver breamBlicca bjoerknaand burbotLota lota; marine species, the pale eelpoutLycodes pallidus, the snakeblennyLumpenus lampretaeformisand northern wolffishAnarhichas denticulatus. The presence of the merlingMerlangius merlangusin the White Sea was confirmed. Taking into account literature data, the White Sea ichthyofauna includes 86 species and subspecies from 33 families (54 marine species, 14 anadromous and semi-anadromous species, and 18 freshwater species entering brackish waters). The marine ichthyofauna is basically represented by 17 families: Petromyzontidae, Clupeidae, Osmeridae, Coregonidae, Salmonidae, Gadidae, Gasterosteidae, Cottidae, Agonidae, Cyclopteridae, Liparidae, Zoarcidae, Stichaeidae, Pholidae, Anarhichadidae, Ammodytidae and Pleuronectidae. Representatives of the other families are few or rare, or occur in low salinity estuarine areas. The catches of some species have not been recorded for half a century. The group of commercial fish species includes 23 species; Clupeidae, Osmeridae, Coregonidae, Salmonidae, Gadidae, and Pleuronectidae form the basis of fishery.
Voprosy ihtiologii. 2025;65(1):3-21
3-21
Records on the herring shark Lamna ditropis (Lamnidae) and its embryos in the surf zone of Kunashir Island (South Kuril Strait) in February 2024
Abstract
The discovery of a female salmon sharkLamna ditropisand two its embryos in the surf zone ofKunashir Island is reported. Data of morphometric measurements of the female are presented.TLof the female was 216 cm;aC, 195 cm. Cephalopod (Cephalopoda) beaks and codfish (Gadidae) otoliths have been found in the stomach of the shark. It is assumed that the stress trigged premature parturition.
Voprosy ihtiologii. 2025;65(1):22-31
22-31
Vertical structure of the fish community in the Pacific zone near the northern Kuril Islands
Abstract
Seasonal bathymetric movements of fish in the subarctic waters of the Far Eastern seas have a significant impact on the distribution of all fish and make important changes in the structure of the species composition of the ichthyofauna on the shelf and continental slope. The purpose of this work was to determine the vertical structure of bathymetrical communities of fish in the Pacific waters of the northern Kuril Islands and its seasonal changes. The main material for the article was the data collected during trawl surveys in the period 1987–2021. It is shown that the boundary between the elittoral and mesobenthal communities in the cold season of the year was in nearly 350 m, in the warm period of the year it shifted to a depth of 100 m. The new information makes it possible to assess the characteristic features of elittoral and mesobenthal communities and seasonal changes in the intermediate boundaries between them and clarifies the scale of migration processes during annual life cycle of fish in the area.
Voprosy ihtiologii. 2025;65(1):32-60
32-60
Distribution and size composition of the snowy sculpin Myoxocephalus brandtii (Cottidae) near the mainland coast of the northern Sea of Japan
Abstract
Two groups of the snowy sculpinMyoxocephalus brandtiihave been identified off the mainland coast of the northern part of the Sea of Japan, separated by the area of pronounced dynamics of water masses near the 43th N parallel. Individuals of the southern group reach a length of 48 cm and those living to the north, 51 cm. From early spring to late fall, the snowy sculpin inhabits depths < 1 meter. In summer, it is found up to 100 m, concentrating mainly at 11–30 m. In autumn, it moves to shallow waters, where it begins spawning in late November at depths ~ 4–7 m. In winter, some males remain to guard clutches of eggs, while the remaining fish of the spawning part of the population move away from the upper part of the shelf, spreading to a depth of 141 m. Immature individuals throughout the year live mainly in the upper part of the shelf, which is most exposed to seasonal changes in temperature, as they are more eurythermal than adults. In summer, the snowy sculpin prefers temperatures of 8.1–18.0°C. Adults are found in waters warmed to no higher than 20°C and juveniles, up to 22.5°C.
Voprosy ihtiologii. 2025;65(1):61-72
61-72
Dynamics of the Timing of Mass Spawning for Saffron Cod Eleginus gracilis in the Amur Bay, Sea of Japan
Abstract
The dates of the beginning and end of mass spawning and their interannual variability were determined based on the data of long-term monitoring of sexual maturity for saffron codEleganus gracilisduring its under-ice spawning period in the Amur Bay of the Sea of Japan. A tendency to earlier spawning and several shifts in this process associated with changes in environmental conditions, in particular, with climatic changes caused by global warming were found. The dates of spawning of saffron cod depend on conditions of summer-autumn feeding and maturation of fish in previous seasons: the warmer the subsurface water layer, the earlier saffron cod spawns. As a result, the period of mass spawning of the species in the study area, which began on average on December 25 and ended on January 12 in the 1970s, shifted to the period from December 18 to December 30 by 2021–2023. Besides, intraseasonal patterns of the spawning process are found, as several spawning runs in some years. The early run is presumably characteristic of younger fish that feed in the coastal zone, while older individuals of saffron cod run later due to feeding at greater depths and at lower temperatures.
Voprosy ihtiologii. 2025;65(1):73-83
73-83
Forage base and feeding of the sea of Okhotsk pink salmon Oncorhynchus gorbuscha (Salmonidae) during marine migrations in the sea of Okhotsk and adjacent waters of the pacific ocean
Abstract
The forage base of the pink salmonOncorhynchus gorbuschaduring its marine migrations in the Sea of Okhotsk (August−December) is sufficient for feeding and migration of juveniles of this species despite significant changes. According to long-term data, the daily ration of juvenile Sea of Okhotsk pink salmon was 7−10 in summer and 4.0−4.5% of the body weight in autumn.At the beginning of the winter period, in December, the biomass of forage plankton in the epipelagic zone in the Sea of Okhotsk and northwestern Pacific waters off the Kuril Islands decreased by an average of 1.5 times, in the upper epipelagic zone, by more than two times. However, the feeding intensity of juvenile pink salmon decreased slightly in December compared to October–November, mainly due to large interzonal copepods (Copepoda) due to their seasonal migrations to the mesopelagic zone for wintering. The minimal biomass of forage plankton (on average 204.1 mg/m3) and low feeding intensity of pink salmon (daily ration of 3.1%) were observed during the typical winter period, in January. In late February-early April (winter-spring period in most of the studied water area), large interzonal copepods migrate to the epipelagial after wintering, their proportion of the forage plankton was 48.9%, as a result, the average biomass of the latter increased more than twice (up to 459.4 mg/m3). The feeding intensity of pink salmon also increased (daily ration 3.6%). During spring and summer periods, the biomass of forage plankton in the epipelagial increased significantly to 718.7 and 820.2 mg/m3, respectively. Pink salmon fed intensively before the beginning of pre-spawning migrations. In July, despite a favorable forage base, the feeding intensity of migrating pre-spawning pink salmon was minimal: in open waters the daily diet was 3%, closer to the coast, 1−2%.
Voprosy ihtiologii. 2025;65(1):84-103
84-103
Activity of enzymes of energy and carbohydrate metabolism in the organs of pink salmon Oncorhynchus gorbuscha (Salmonidae) during spawning migration
Abstract
The article presents the results of the study of the activity of key enzymes of energy and carbohydrate metabolism in pink salmonOncorhynchus gorbuschaspawners during spawning migration from the estuary to the river. A decrease in the activity of carbohydrate metabolism enzymes (lactate dehydrogenase and pyruvate kinase), 1-glycerophosphate dehydrogenase in red muscles and liver, as well as cytochromecoxidase and aldolase in white muscles in fish at the river stage of the migration route has been shown. Relatively higher values of cytochromecoxidase activity in gills, glucose-6-phosphate dehydrogenase in red muscles, and aldolase in the liver were found in fish caught in the river. Apparently, as pink salmon spawners move to spawning grounds, metabolic changes occur associated with the redistribution of substrates towards increased use of lipids and proteins of muscle tissue to provide energy for the process of osmoregulation, high physical activity and reproductive function under conditions of complete exogenous starvation.
Voprosy ihtiologii. 2025;65(1):104-113
104-113
Thermopreferential behavior of the Senegal bichir Polypterus senegalus (Polypteridae) under chronic visual deprivation
Abstract
The effect of chronic visual deprivation (eye lens removal, 3 months) on the thermopreferential behavior and preferred temperature in fish was studied for the first time on the example of the Senegal bichirPolypterus senegalus. In intact Senegal bichir, the thermopreferential range and mean preferred temperature are 32.0–35.0 and 33.8°C, whereas in visually deprived fish they are 26.0–35.0 and 30.2°C, respectively. Compared to intact individuals, the visually deprived fish are more mobile and make 10.3 times more travels from compartment to compartment in the thermogradient tray, their total travel distance is 16.9 times longer, and the distance swum without change of direction is 1.6 times longer and takes 8.7 times less time. The rate of temperature change during movements in visually deprived fish is 14.9 times higher than in intact individuals. Changes in thermal preference and movement activity found in fish experiencing chronic visual deprivation indicate the presence of complex relations between thermoreception and the visual system.
Voprosy ihtiologii. 2025;65(1):114-123
114-123
КРАТКИЕ СООБЩЕНИЯ
The first capture of the whiting Merlangius merlangus (Gadidae) in the Dvina Bay of the White Sea
Abstract
WhitingMerlangius merlangus(Linnaeus, 1758) was first recorded in the Dvina Bay of the White Sea in May 2015. In June and August 2023, four more specimens were caught in the apex of the Dvina Bay. The paper presents morphometric and some biological data on the preserved specimen. The whiting is characterized by a southern boreal distribution and is not a typical representative of the White Sea ichthyofauna. Apparently, its captures are associated with the introduction of juveniles into the White Sea.
Voprosy ihtiologii. 2025;65(1):124-128
124-128
On the reproduction of the curled picarel Centracanthus cirrus (sparidae) in the Black Sea
Abstract
The article presents a description of the larva of the curled picarel Centracanthus cirrus Rafinesque, 1810, caught in the northern part of the Black Sea off the coast of the Crimean Peninsula in the waters of the Koktebel Bay near Cape Malchin (Karadag Nature Reserve). The occurrence of the curled picarel larva in the ichthyoplankton of this area indicates the reproduction of this species in the Black Sea and thus confirms its adaptation to new environmental conditions and the expansion of its range in the seas of the Mediterranean basin.
Voprosy ihtiologii. 2025;65(1):129-134
129-134
Peripheral blood leukocyte composition of the Atka mackerel Pleurogrammus monopterygius (hexagrammidae) and chum salmon oncorhynchus keta (Salmonidae) from the Bering sea
Abstract
In the Atka mackerel Pleurogrammus monopterygiusand chum salmon Oncorhynchus keta from the Bering Sea, lymphocytes predominate among leukocytes in peripheral blood. Atka mackerel lacks segmented neutrophils and basophils, while chum salmon lack eosinophils. The studied species differ in the size of leukocytes and the values of the leukocyte abundance index.
Voprosy ihtiologii. 2025;65(1):135-142
135-142