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Vol 203, No 3 (2023)
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BIOLOGICAL RESOURCES

465-489 367
Abstract

For pacific cod in the northwestern Bering Sea, biomass of the summer-fall feeding aggregations in the specified area of their highest density (polygon) is considered as a stock unit. The fish in these aggregations belong to the populations spawn in both local and adjacent areas. The stock values, biological parameters, and annual catches are determined for the period from 1965 to 2022 on the materials collected in research surveys and commercial expeditions, as well as on the data of fishery statistics and cited data. The average length of cod caught by different commercial fishing gears is determined as 42.01 cm for Danish seine, 53.01 cm for bottom trawls, 58.15 cm for midwater trawls, 61.94 cm for longlines. The midwater and bottom trawls used in research surveys are equipped with the rigging for better account of juvenile fish, therefore the average length of cod in their catches is 46.42 and 36.52 cm, respectively. The cod aged from 3 to 12 years are presented in the longline catches, with the modal group of 5 years old, but the age range is wider for bottom trawls, from yearlings to 12–13 years old fish, with a modal group varying from 2 to 5 years old in different years. The parameters of von Bertalanffy equation of linear growth for pacific cod are determined as: L∞ = 111.993 cm, K = 0.159, and t0 = –0.024 and for the equation of weight growth rate: W∞ = 14.006 kg, K = 0.245, and t0 = 1.221. The age of mass maturation is 4.4 years. The instantaneous coefficient of natural mortality, calculated by Tyurin, is age-dependent, with the minimum for 5 years old fish (0.345 year–1), 1.245 year–1 for yearlings, 1.231 year–1 for 11 years old fish, and 1.860 year–1 for 12 years old fish. History of the cod fishery in the northwestern Bering Sea is traced since its start in 1965. The cod fishery was realized with various types of fishing vessels (from small seiners to supertrawlers) and fishing gears, but the bulk of annual catch was landed with longlines (65.9 % in the 2010–2022, whereas only 21.4 % was landed with bottom trawls and 12.7 % with Danish seine). Overfishing happened in 1971, when the annual catch increased to 91,600 t on the background of poor replenishment, after that the catch decreased to 760–1420 t in 1976–1979. Then the stock had recovered and the catch increased from 3890 t in 1980 to 58,480 t in 1986. Next decline to 13,810 t in 2009 was followed by a new growth to the record value of 106.2 . 103 t in 2020, but recently the annual catch decreased again (61.5 . 103 t in 2022). This dynamics corresponded to the stock fluctuations: according to the trawl surveys data, the spawning stock within the polygon ranged between 66.5–282.6 . 103 tons in the 1965–1974, decreased to 24.5 . 103 t in 1977 because of overfishing, gradually recovered to 108.1 . 103 t in 1980, 173.0 . 103 t in 1982, and 561.6 . 103 t in 2000, then declined again to 151.4 . 103 t in 2001 and grew in the last two decades to the maximum values of 1,297.9 . 103 t in 2018. Recently a rapid decline of the stock is observed to 475.0 . 103 t in 2022. The changes of the assessed spawning stock generally precede for two years the CPUE changes due to relatively younger age composition in the catches of research bottom trawl used for the stock calculation, in comparison with the age composition in commercial catches. The stock dynamics within the polygon in the northwestern Bering Sea is driven by variations of the cod feeding migration to this area that correlates with the extension of the coldwater pool at the sea bottom around St. Lawrence Island. From the other hand, the migration depends on the cod abundance on the spawning grounds that could be negatively impacted by the bottom trawl fishery in the spawning season. Since 2002, the fishing pressure was moderate, and fishing mortality did not exceed the fishing exploitation target. However, overfishing is possible in the next 3–4 years, if the fishing mortality goes beyond the target benchmark.

490-498 319
Abstract

Fish species distribution in Lake Lebedinoye is considered. The samples were collected by fry seine along entire coast of the lake. Ten species of fish were sampled in the coastal zone; juveniles of chum salmon Oncorhynhus keta, amur stickleback Pungitius sinensis, and japanese dace Tribolodon hakonensis were rather abundant, other species were few in number. Japanese huchen Parahucho perryi were noted among the latter species: both juveniles of different age and an adult specimen of ≈ 2 kg weight were caught.

499-518 346
Abstract

Cited information on gametogenesis of pink salmon Oncorhynchus gorbuscha Walbaum is summarized. Periods of indifferent development and sex differentiation are considered, development of the testes and ovaries is traced, and the fertility formation is analyzed. Regularities of sex reversion, unique for salmonids, and evolutionarily acquired specific features of oogenesis associated with a short life cycle are noted.

519-528 293
Abstract

New data on biology of hair crab Erimacrus isenbeckii are presented and ecological and geographical variability of this species is discussed. Molting, growth, sex and size structure of the crab are considered on the data collected in the Shelikhov Bay of the Okhotsk Sea in September-October, 2022. The male : female ratio of E. isenbeckii in the trap catches was 14 : 1. Gender differences in their age, weight, and carapace width were not significant (p < 0.05). The maximum size of E. isenbeckii in the Shelikhov Bay was 104 mm that is less the size values at the western coast of Kamchatka, southward from Kamchatka, and in the Aniva Bay of Sakhalin Island, and much smaller the crabs from the waters of Hokkaido Island and Alaska Peninsula. Rather high portion of the males on the 3rd intermolting stage was detected (57 %). The age composition of males varied significantly in dependence on stage of molting (p < 0.05). A freshly molted female on the 1st intermolting stage with an unoccluded genital opening was caught together with its exuvia. After molting, within the crab trap, it had increased the width of carapace in 6 mm. This new information could be used in monitoring of the E. isenbeckii population in the Shelikhov Bay.

ENVIRONMENTS OF FISHERIES RESOURCES

529-549 364
Abstract

Structure and functional characteristics of zooplankton and feeding of the most abundant nekton species (pollock, herring and salmons) are analyzed using the data of ecosystem survey in the western Bering Sea in 2020 and compared with the structural indices for 2015−2019. The main patterns of composition and distribution of zooplankton and production of organic matter by zooplankton are determined. High values and turnover rate of production are noted for the non-predatory zooplankton (mainly copepods and euphausiids) in the eastern Anadyr Bay, the area at Cape Navarin, the shelf of Koryak coast, and the continental slope of Olyutorsky Bay. High production of predatory zooplankton (mainly hyperiids) is found on the slope of Karaginsky Bay, presumably because of these species transport from the southern areas with later stage of the seasonal succession. In autumn 2020, walleye pollock and pacific herring consumed from 15 to 55 % of the copepod, euphausiid and hyperiid production. This level of consumption did not affect their food supply because of very high turnover rate of these taxonomic groups of plankton. In the deep-water areas, salmons did not use more than 3 % of their food resource. Thus, the survey data indicate a good food supply for the most abundant nekton species in the western Bering Sea in the fall season.

550-566 252
Abstract

To compare trophic characteristics for pelagic and bottom communities of zooplankton and zoobenthos in the western Chukchi Sea, isotopic composition of carbon and nitrogen (δ13С and δ15N) is determined for three different types of water masses. The main area of the southwestern part of the sea (to the south of 71оN) is occupied by the surface and subsurface water masses invaded from the Bering Sea with relatively high δ13C and low δ15N values. The cold Arctic waters prevail in the northwestern area. The western periphery of the sea is influenced by the water masses from the East Siberian Sea transported by the alongshore  Siberian Current, distinguished by significantly lowered δ13С values and somewhat (by 1–3 ‰) increased δ15N values. A stable difference in the carbon isotopic composition between zooplankton and benthic invertebrates is revealed in the southwestern Chukchi Sea that means that the benthic organisms are based mainly on the bottom food chain, with a minimal input of organic matter from the water column. In the area influenced by the water masses from the East Siberian Sea, benthic invertebrates have the lowest values of δ13С comparable to those of zooplankton that is a sign of organic sediments from the water column utilization, partly terrigenous in origin. The role of primary producers for plankton and benthos in the northwestern Chukchi Sea has not been fully elucidated and requires additional studies. However, the main trophic base for the benthic community is assumed there to be organic matter removed from the water column, originated mainly from ice algae.

567-580 237
Abstract

Amphipods (mainly hyperiids) are among the top-five taxonomic groups in the diet of many nekton species. Feeding of 106 nekton species dwelled in the Okhotsk Sea is considered (though 93 % of the stomach samples were collected from only 20 mass species). Amphipods are found in the food of 83 species and are absent for 23 species. Taxonomic composition of Amphipoda coincides in plankton and stomach samples; 3 species of hyperiids dominate here and there: Themisto pacifica, T. libellula, Primno macropa. The portion of amphipods in food is the highest for fish with length of 30–40 cm, decreases for smaller and larger fish, and practically disappears for fish with the length > 60 cm. In the food of mass commercial fish species, as pollock, cod, herring, silverfish, char, and pink, chum, sockeye and cherry salmon, the portion of hyperiids in the food could be almost 100 %, with CI of 200–700 ‱. During the daytime, the portion of large-sized hyperiids decreases up to 3 times, as they descend deeper than 200 m. T. pacifica have the highest biomass in the southern Okhotsk Sea, with a long-term tendency to increasing, and the lowest biomass in the northern Okhotsk Sea, with a tendency to decreasing both in the northern and central parts of the sea. P. macropa have similar spatial patters of distribution, but dynamics of their biomass has negative trend in the northern part, positive trend in the central part, and no trend in the southern part of the sea. On the contrary, the biomass of T. libellula is the highest in the northern Okhotsk Sea.

581-600 247
Abstract

At least 10 communities of macrozoobenthos are determined by modern statistical methods on soft sediments in the coastal areas of Peter the Great Bay with the depth of ≥ 5 m surveyed in 1992, 1993 and 1996. They were: I. Scoletoma spp. + Ophiura sarsii; II. Aphelochaeta pacifica (I–II — in the Strelok Bay and Rifovaya Inlet); III. O. sarsii +  Amphiodia fissa; IV. Scoletoma spp. + Mactra chinensis; V. Scoletoma spp. + Maldane sarsi; VI. Acila insignis (III–VI — in the Posyet Bay and adjacent area); VII. Scoletoma spp. + Echinocardium cordatum; VIII. Dipolydora cardalia + M. sarsi + O. sarsii; IX. Spiophanes uschakovi + E. cordatum, and X. Ampelisca macrocephala (VII–X — in the area at the Tumannaya/Tumen River  mouth). Their  development  was  determined  by  such  environmental  imperatives as the bottom sediments properties (silting degree, mean grain size), depth, and level of pollution and eutrophication. Majority of these communities (I, III, IV, V, VII, VIII, IX, and X) were in good ecological condition. Their habitats were slightly disturbed (intact or almost intact) and rare or never polluted and eutrophicated. The community II occupied more disturbed habitats with moderate ecological status reflected in higher indices of pollution. This community was rather likely formed in the process of succession in conditions of decreasing pollution. The community VI had a lower ecological status; its differentiation was probably caused by specific oceanographic regime of the Posyet Bay and anthropogenic impacts.

601-617 254
Abstract

Year-to-year variations of temperature in the upper mixed layer are considered for the ice-free waters of the Bering Sea in cold season (from December to March) using all data of the deep-sea oceanographic observations available to date (12,430 stations for the period from 1943 to 2022). Series of annual mean fields of the mixed layer temperature in December-March were decomposed by applying the empirical orthogonal function (EOF); dynamics of the first two components of decomposition (described in sum 50.4 % of the initial fields variability) are analyzed. The first component (32.4 % of variation) indicates synchronous oscillations over the entire sea area with the maximum contribution at the continental slope. The second component (18.0 % of variance) reflects opposite oscillations in two vast regions of the sea located along the continental slope from Cape Navarin to Alaska Peninsula and in the western, central and southern parts of the deep basin. The following statistically significant periodic oscillations are revealed by spectral analysis: quasi-biennial and those with periods of 4, 7, and 17–20 year for the 1st EOF and quasi-biennial and those with periods of 3 and 4 year for the 2nd EOF. A statistically significant linear trend to warming is detected for the time coefficient of the 1st EOF in the period of 1958–2022. Approximation of this coefficient dynamics with 6-degree polynomial function (polynomial trend) shows a tendencies to the mixed layer cooling in winters of 1969–1972 and 1992–2004 but the opposite tendencies to warming in 1973–1991 and 2005–2022. Variations of time coefficient for the 2nd EOF correspond to opposite tendencies in the areas with positive and negative values of this EOF. For the period from 1958 to 2022, winters in the Bering Sea are classified by the mixed layer temperature, taking into account the contribution of the 1st EOF only, as «warm» (1958, 1959, 1963, 1964, 1966, 1979, 1982, 1985, 1987, 1997, 2001, 2003, 2004, 2015–2018, 2020, and 2022), «normal» (1960–1962, 1965, 1967, 1968, 1970, 1971, 1974, 1978, 1980, 1981, 1983, 1986, 1989–1994, 1996, 1998, 2005–2007, 2011, 2013, 2014, 2019, and 2021), «cold» (1969, 1972, 1973, 1975–1977, 1984, 1988, 1995, 1999, 2000, 2002, 2008, and 2010), and extremely cold (2009 and 2012).

618-638 266
Abstract

At least 16 communities of macrozoobenthos are determined by modern statistical methods on soft sediments in the coastal areas with the depth of ≥ 5 m of Peter the Great Bay at Vladivostok surveyed in 2001–2019. They were: I. Scoletoma spp. + Sigambra bassi; II. Scoletoma spp. + Ophiura sarsii; III. Philine orientalis + Macoma sp.; IV. Aphelochaeta pacifica; V. A. pacifica + Capitella capitata; VI. O. sarsii + Macoma scarlatoi; VII. O. sarsii + Scoletoma spp. + Scoloplos armiger + Ennucula tenuis; VIII. Phoronopsis harmeri; IX. Maldane sarsi; X. A. pacifica + Dipolydora cardalia; XI. Scoletoma spp.; XII. Praxillella gracilis + Pelonaia corrugata, XIII O. sarsii + Acila insignis, XIV Scoletoma spp. + O. sarsii + M. sarsi; XV. Scoletoma spp. + M. scarlatoi, and XVI. A. pacifica. Their differentiation was determined by such environmental imperatives as the level of chemical pollution, eutrophication, and impact of terrigenous water discharge. By biotic indices (AMBI, M-AMBI, TPFbio), the most damaged and environmentally disturbed communities were IV, V, and XVI inhabited the Golden Horn Bay and Diomid Inlet. The communities of the East Bosphorus Strait (III, VI) have higher ecological status that increases even more in the Amur and Ussuri Bays (communities I, II, VII, XII, XIII, XV, XIV), except of the northern tips of both bays (IX, XI) and the eastern part of the Amur Bay (VIII, X). With such bioindicative approach, ecological status of the communities is described more concisely and visually than with indices of species richness, diversity, or W-statistics.

639-649 233
Abstract

Oceanographic and ecological properties were measured in the Novik Bay of Russky Island (Japan Sea) in early spring (April) of 2023, the indicating groups of microorganisms were examined. Good ecological state of the bay waters was detected. Stable density stratification was already formed, with the water temperature range from 2.3oС at the bottom to 10.0oС on the sea surface and salinity from 33.6 to 31.1, respectively. Dissolved oxygen content was high in the bottom layer (9.6–10.8 mg/L). In the surface layer, the oxygen content was lower, as well as chlorophyll a concentration. Abundance of the colony-forming heterotrophic microorganisms was rather low, so the waters of the bay were characterized as oligosaprobic and pure that indicated accumulation of easily accessible organic matter (accumulation predominated over destruction), apparently due to development of production processes. Some exceptions with zero balance between the production and destruction were found in the Trud Inlet, in the inlet of Sports Club, and at Podnozhye village. Bacteria of the sanitary-indicative group were recorded in small quantities at two stations where they indicated biological and fecal pollution of the water. Microorganisms growing on media with crude oil were observed everywhere, although their number was not high, so the waters of the Novik Bay were identified as low-polluted, in general. However, high abundance of phenol-resistant microorganisms at most of the stations was a signal of significant pollution by phenols, that could have both natural and anthropogenic sources. Metal-resistant microorganisms were not abundant in the surface layer that showed the minimal level of technogenic pressure. Their dominant group was Ni-resistant heterotrophs associated with combustion of hydrocarbon fuel.

650-667 289
Abstract

On the background of water structure, general patterns of the sandfish Arctoscopus japonicus distribution in Peter the Great Bay are determined on the data of bottom trawl surveys in spring, summer and fall seasons. When the larval stage is finished, the underyearlings of sandfish appear in the trawl catches since July. Depth of their catches by bottom trawl in July-August is 23–60 m, under the temperature of 8–16 о С. Localization of the catches at the upper benthic front corresponds to their pelagic spreading with concentration on the seasonal thermo-pycnocline, so the belts of high catches by bottom trawl are located along the line of the thermocline contact with the bottom. They convert to bottom dwelling in fall season, being concentrated below the benthic front and shifting deeper gradually with the front. The adults dwell at the bottom, permanently in the subsurface waters. Their feeding starts near the coast in May-June when they aggregate below the upper benthic front, avoiding the remnants of the cold Bottom Shelf water mass. Under thickening of the warm surface layer in July-September, they retreat deeper and spread widely at the shelf bottom within the area occupied by the Subsurface Shelf water. Pre-spawning aggregations of adult sandfish are formed at the shelf edge and upper continental slope in October, whereas the non-spawning fish stay in this month on the shelf together with the underyearlings. The adults migrate to the coastal zone in November for spawning on seaweeds. The southern part of the bay is presumably more favorable for the spawning of sandfish, as the underyearlings are absent in its northern part in summer. The sandfish adults wintering is available outside the bay, so the southward migration is supposed in late autumn and the backward migration in spring.

668-675 243
Abstract

Nonlinearity effect of the seawater density equation for mixing of waters with different salinity is considered for a case of the halocline formation in estuaries. Depending on salinity, density of the mixture can be higher (at low salinity) or lower (at high salinity) than the arithmetic mean density of the two components, so an effect of compaction during mixing (cabbeling) is observed in the upper part of halocline with lower salinity, whereas an effect of decompaction during mixing (anticabbeling) occurs in its lower part with higher salinity. The salinity value at the point of cabbeling change to anticabbeling is calculated that depends on average temperature of the mixed waters. In the real halocline (estuary of the Razdolnaya/Suifen River flowing into Peter the Great Bay, Japan Sea), the highest vertical gradient of salinity is observed along the isohaline, which value changes depending on temperature. In summer, when the water temperature in the estuary is about 22 oC, the maximum gradient is observed at the isohaline 10 psu, while in winter, when the temperature drops to 1 oC, the maximum gradient shifts to the isohaline 18 psu. These isohaline values correspond to the salinity values for the point of cabbeling change to anticabbeling. The cabbeling effect above this level promotes sinking of water, but the anticabbeling effect below this level promotes rising of water. This encountering convergent motion is an additional mechanism of the halocline self-sustaining in sharp state.

TECHNOLOGY FOR PROCESSING OF AQUATIC ORGANISMS,

676-685 208
Abstract

Enzymatic hydrolysis of seaweed and seagrass (anfeltia Ahnfeltia tobuchiensis, laminaria Saccharina japonica, and eelgrass Zostera marina) is investigated. The enzyme preparation Viskoferm was the most effective for the mixture of these macrophytes, with high content of laminaria and eelgrass, under conditions of temperature 65 оC and pH 6.0. The hydrolysis in 16 hours reduced content of high-molecular polysaccharides and increased the portion of easily hydrolysable carbohydrates. Feeding of the sea cucumber juveniles by compound feeds with this fermented mixture of macrophytes had a positive effect on their physiological state; the food was easily digested by the animals and provided good gains. The average daily weight gain of juvenile sea cucumber in hatchery conditions had increased by 1.2 times in case of using the starter compound feed and by 1.5 times — for breeding with the productional compound feed.

686-694 233
Abstract

Production  of  biodiesel  from  the  fat-containing  entrails  of  king  crab  is investigated. These secondary raw materials are massively disposed (released into the sea) after separation of limbs. Routine technologies of the biodiesel production from vegetable and fish oils are used. The fatty acid composition of the fat is analyzed and the acid and peroxide numbers are determined. A high content of PUFAs (42.5 %) is detected, including the omega-3 (30.6 %) and omega-6 (12.3 %) fatty acids. High acid number (5.5 mg KOH per g fat) and peroxide number (85.6 mmol of active oxygen per g fat) of the crab fat do not meet the requirements for edible fish oils. The biodiesel in the form of fatty acid ethyl esters was produced from the crab fat with three indicators (NaOH, KOH, and H2SO4). Reactions with alkali did not give positive results due to formation of large amounts of soap. The best yield of esters was obtained in the experiment with sulfuric acid: 52.2 g of biodiesel was produced from 50.0 g of fat. Mechanisms of the reaction are explained and mass balances of the process are presented. Kinematic viscosity, total contamination, and acid number of biodiesel (4.96 mm2/s, 8 mg/kg, 0.35 mg KOH/g, respectively) meet the requirements of the national standard GOST R 53605-2009 (EN 14214:2003).

695-709 290
Abstract

Scientific and practical aspects are considered for development of functional nutrition products from fish raw materials after lifetime enrichment of the fish muscle tissue with selenium. Size-weight composition is investigated for rainbow golden trout grown in aquaculture, minerals and fatty acids content is determined for hot-smoked products of this species, and quality indicators and nutritional value are evaluated for both raw materials and the products to examine possibility of the enrichment with selenium by adding a selenium-containing preparation to fish feeds and to estimate effect of such feeding on commercial, nutritional and consumer properties of the products. The fish from the experimental group fed by the feeds with preparation Kormogran Selenium-3 had more valuable mineral and fatty acid composition of meat, higher yield of edible parts, and better organoleptic properties of smoked products in comparison with the control group. There is concluded that the lifetime enrichment of the trout tissues with selenium in aquaculture conditions is an effective technology for producing high-quality seafood for functional nutrition.

METHODS OF INVESTIGATIONS

710-721 192
Abstract

A method for grouping one-degree trapezoids into biostatistical areas of any size is proposed. For this purpose, all stations of survey are marked by the number of trapezoid, its area and central coordinates. Then the stations are sorted by the trapezoid numbers; their biological parameters (biomass, abundance, etc.). The mean values are integral parameters with the weights proportional to size of trapezoids — they can be easily grouped into small or large areas of any shape, depending on research tasks.

SCROLLS OF MEMORY

722-743 478
Abstract

Biography of Gavriil Mikhailovich Biryulin, a well-known oceanographer in scientific community and a writer popular in his time among fans of science fiction. His scientific and writing activity is described in details, as well as the life and scientific achievements of his family members who worked or trained in TINRO. His wife Lyudmila Viktorovna Mikulich was an ichthyologist and university lecturer, his daughter Maria Gavrilovna Biryulina was an ichthyologist and paleontologist, and his stepson Lev Petrovich Yakunin was an oceanographer and head of the Oceanography department at the Far-Eastern University.



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