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Izvestiya TINRO

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Vol 200, No 2 (2020)

BIOLOGICAL RESOURCES

245-269 982
Abstract
Current state of the red king crab population at West Kamchatka is considered on the data of bottom trawl surveys and fishery statistics since 2013. Some biological parameters of the crabs and assessments of the commercial stock are presented; recent condition of the red king crab fishery and evaluation of the total allowable catch are discussed. The red king crab fishery was resumed in 2013, after 8 years of ban caused by the population decrease. During the ban, the stock restored and exceeded the value observed before the ban: the total accounted abundance of red king crab in 2017 was about 244 . 106 ind. that was the highest level for the last two decades, with the number of commercial males estimated as 110 . 106 ind. — this amount was never observed before on the shelf of western Kamchatka, at least in four decades of surveys. Recently the northern forbidden district and Khayryuzovsky district of the shelf zone lost their role of the main areas of crabs reproduction and their juveniles feeding, in favour to the Ichinsky district located southward. Recent fishery of red king crab is fruitful and sustainable. In the last 3 years, the major part of annual catch is transported alive to ports of China and South Korea. For this purpose, the caught crabs are sorted strictly aboard fishing vessels and the largest males are released back to the sea. Possibly, year-to-year increasing of the males size on the West Kamchatka shelf is caused by this sorting and releasing; another effect of the large-sized crabs releasing is relatively low number of recruits in the last couple of years. The fishery elimination coefficient is estimated in the range 5–16 % of the total accounted stock for 2013–2019, that shows a highly precautionary approach. Gradual decreasing of the crab commercial stock is forecasted for the nearest future, though the stock will remain above the target value. Current state of the red king crab population at West Kamchatka is not considered as dangerous, and ongoing intense fishery of this valuable species within the recommended volumes will not affect this sustainable state.
270-291 574
Abstract
Aerial survey of the pacific salmon spawning grounds was conducted in the water bodies of Chukotka belonged to the Bering Sea basin (the Anadyr, Velikaya, Tumanskaya Rivers and Meinypilgyno lake-river system) in 2019, for the first time since 1992. Total flight time was 35 hours, approximate length of the transects was 3,800 km. Number of the spawners was estimated as 660.7 . 103 ind. for chum salmon, 112.2 . 103 ind. for sockeye salmon, and 3678.0 . 103 ind. for pink salmon, features of their distribution are described.
292-307 733
Abstract
istribution of fishes and prawns in the Amur River (40–960 km from the mouth) is described on results of the beam-trawl survey conducted in September-October, 2003 (57 trawl stations at the depth of 1.5–23.0 m). In total, 2584 ind. of 22 fish species and 1077 ind. of 1 invertebrate species (prawn Palaemon modestus) were caught. The highest species richness was registered for orders Cypriniformes (13 species) and Siluriformes (4 species). The fish and prawn stocks were evaluated as 32.161 . 106 ind. (583.8 t) for bottom and near-bottom fish and 4.887 . 106 ind. (8.8 t) for prawns. Two commercial fish species were the most abundant: catfishes Tachysurus brashnikowi (16.26 . 106 ind. or 32.9 % of total biomass) and T. sinensis (4.32 . 106 ind. or 24.0 % of total biomass); other 6 fish species with considerable biomass were lizard gudgeon Saurogobio dabryi (12.6 %), ussuri catfish T. ussuriensis (9.7 %), amur white-pinned gudgeon Romanogobio tenuicorpus (7.8 %), amur sturgeon Acipenser schrenckii (5.6 %), amur gudgeon Gobio cynocephalus (2.4 %), and kaluga Huso dauricus (0.6 %). Distribution density varied in the range of 0.01–2.57 g/m2 (on average 0.45 ± 0.27 g/m2) for fish and 0.005–0.044 g/m2 (0.021 ± 0.012 g/m2) for prawns. Abundance of both fish and prawns increased multifold towards the Amur mouth that correlated with increasing of forage benthos biomass in the same direction. So, the main portion of fish biomass (82.4 %) was distributed in the Amur River downstream (40–400 km from the mouth) and the prawn stock was concentrated completely in its lowermost part (50–150 km from the mouth).
308-320 635
Abstract
Some characteristics of reproductive biology are considered for amur flathead asp Pseudaspius leptocephalus (Pallas, 1776), as features of its spawning, reproduction capability, annual dynamics of oocyte growth and females gonadosomatic index. This is the species with a single batch spawning. Age of maturity for the asps living in different areas ranges from 3+ to 5+, mostly 5+ with the body length of 31 cm for the key fishing grounds. They spawn in the lower sections of mountain rivers from late May till early June. Females prevail in ratio 2 : 1, on average, both in the spawning and feeding aggregations. The individual absolute fecundity of amur flathead asp females depends linearly on their body length and weight.
321-333 462
Abstract
Population structure of crucian carp in a small freshwater lake on Bolshoy Pelis Island is studied on the data of trap catches conducted in 1985, 1995 and 2015. Mature part of the population consisted of fish with length 110–280 mm TL and age from 2 to 8–9 years that are usual parameters for this species. Age was estimated using annuli on fish scale. The largest caught fish was the 14-years female with length 470 mm TL and weight 1650 g. All fish reached sexual maturity at age of 2 years. In the age of 5 years and more, the number of females in the population exceeded the number of males (2♀ : 1♂ in 1985). Length-weight relationship was calculated as W = a . TLb. Growth rate was calculated on length-at-age data. Rate of linear and weight growth of females was higher than males in 1985 and 2015 that is considered as a natural difference. After partial elimination of the population in 1995 under natural reasons (hypoxia and toxic microalgae bloom), growth rate of males and females became equal and number of males increased quickly, they were twice more numerous than females. However, the females prevailed again in the sex ratio in 2015. Rate of linear and weight growth was the lowest in 2015, probably because of high density of the fish population.
334-363 810
Abstract
State of pacific salmon stocks is considered for the basins of the Avacha and Paratunka Rivers in 1985–2019. Significant decline of the stocks is noted that is associated with anthropogenic impact growth. Total number of producers for five salmon species in the Paratunka is almost twice higher than in the Avacha, with the largest portion of pink salmon, then chum salmon, lower portion of coho salmon, and the smallest portions of sockeye and chinook salmons, which need special protection. The main biological parameters of salmons are analyzed for both rivers, as body length, weight, fecundity, sex ratio and age structure, by species. Relationships between the parameters are revealed; their long-term trends are determined. Abundance of wildly and artificially hatched chum salmon is compared.
364-376 420
Abstract
Settlements of bivalve Mya uzenensis are investigated in four littoral areas of the Tauiskaya Guba Bay with different environments. Their density varied from 20 to 194 ind./m2 (518–9680 g/m2) depending on habitat. On suitable soils, the settlements occupied 25–40 % of the littoral zone; the mollusks were distributed mostly in mosaic spots with size 0.5–5.0 m2. Stable settlements in the areas with favorable environmental conditions in the Ola estuary and Vesyolaya Bay were formed by mollusks with shell size of 22.1–91.1 mm and age of 2–14 years. Allometry of the shells growth increased with age until 10 years, then leveled. The stocks of mollusk were assessed for certain areas that allowed to recommend for annual landing 158.4 t of M. uzenensis (7 % of commercial stock).

ENVIRONMENTS OF FISHERIES RESOURCES

377-400 496
Abstract
Contents of hydrocarbons, phenols, DDT and its metabolites, Cu, Pb, DDD/DDE and DDD+DDE/DDT ratios, and total level of chemical contamination (TPF index) in bottom sediments are traced for 16 stations in the coastal areas at Vladivostok in 1982−2018. The content of DDT, Cu and Pb, DDD/DDE ratio, and TPF had increased until the early 1990s and then had some stabilizing; the concentration of hydrocarbons was high and relatively stable until the middle 1990s, then dropped sharply and had new gradual growth since the early 2000s; the values of phenols concentration and (DDD+DDE)/DDT ratio were low until the middle 1990s — early 2000s and then increased swiftly. The reason for the pollution decreasing was possibly the lowering of economical activity in the 1990s. All contaminants and indices are very variable that’s why there is difficult to identify the processes responsible for their long-term dynamics. Conception of assimilatory capacity is applied to the bottom sediments. Self-purification of the sediments and maintenance of their contaminants balance is likely provided by microorganisms activity coupled with accumulation of contaminants by macrobenthos in the Amur Bay, by the microorganisms activity coupled with high rates of sediment accumulation in the Golden Horn Bay, and by the microorganisms activity and hydrodynamic sorting of sediments that washes the fine fractions enriched by contaminants in the open areas of the Ussuri Bay. Modern increasing of phenols concentration reflects probably a tendency to eutrophication. Situation of negative impact of chemical contamination (exceeding of ERLq threshold value) is detected for the last 35 years in the Golden Horn Bay but this period is much shorter in other areas with the minimal time in the open Ussuri Bay. The time of negative impact is strongly correlated with the total level of chemical contamination of sediments.
401-411 548
Abstract
Data on dissolved organic concentration (DOC) and concentration of nutrients (phosphorus, silicon, and nitrogen of ammonium, nitrite and nitrate) in the Razdolnaya/Suifen River water are presented. The samples were collected fortnightly, as a rule, during more than a year (2013–2014). The nutrients concentration decreased and DOC and humic substances concentration increased with the river run-off increasing. In conditions of monsoon climate, the nutrients discharge from the Razdolnaya/Suifen into the Amur Bay had great pulsations that promoted sometimes producing of «excessive» phytoplankton biomass in the bay and provided a background for hypoxia at the bottom. Natural terrestrial fluxes of nutrients and DOC into the bay are much higher than these substances supply with waste waters of Vladivostok City. Interannual variability of the nutrients and dissolved organics fluxes into the Amur Bay is traced. Tendency to their increasing is supposed since 2003 because of the Razdolnaya/Suifen River annual discharge increasing observed by Hydrometeorological Agency in 2003–2017.
412-426 588
Abstract
Averaged schemes of the geostrophic circulation on surface of the eastern Okhotsk Sea in winter months are plotted using the data of satellite altimetry measurements. Variations of the surface water transport by the West Kamchatka Current through the latitude of 54о N, between 153о E and the coast of Kamchatka, are analyzed. The current was strengthened in the winters of 1996, 1997, 2009, 2010, and 2013; it was relatively weak in the winters of 2002, and 2007. Statistical dependences of the sea surface temperature and ice cover on the West-Kamchatka Current intensity are calculated for entire winter season and by months; they are statistically significant for all winter months. The West Kamchatka Current variation determines up to 33–36 % of these indices variability.
427-444 546
Abstract
Age of ice in the Okhotsk Sea in 2001–2019 is determined by analysis of satellite data from passive and active microwave spectroradiometers. The areas with certain age composition are contoured with monthly discreteness. Mean thickness of ice in these areas is calculated by weighted averaging of thickness for three main forms, neglecting the ice deformation. The ice volume is calculated by these areas, taking into account the ice concentration. The total mean winter ice volume in the Okhotsk Sea decreased in two decades with the rate of 32.2 km3/decade, on average, while the ice cover decreased by 3.2 %/decade and the average ice thickness decreased by 3.4 cm/decade. Total loss of the ice volume in the Okhotsk Sea in 2001–2019 is estimated as 34.5 %. The ice volume decreasing was caused by both ice thickness lowering (60 %) and ice cover reduction (40 %).

AQUACULTURE

445-459 627
Abstract
Biological and production indices are presented for spawning females of triple hybrid between russian sturgeon, siberian sturgeon and amur sturgeon (RS × SS) × AS and other commercial forms of sturgeon grown in cages of the warm-water fish farm in Luchegorsk, Far East of Russia. In conditions of warm-water pools, survival rate of the triple hybrid larvae and juveniles was higher than that of amur sturgeon and russian-siberian hybrid sturgeon. Weight of the triple hybrid specimens at the age of 3 and 4 years was 1.58 kg and 2.36 kg, respectively, that was higher than that of the russian-siberian hybrid sturgeon and close to the values for amur sturgeon. Fish harvest reached 94 kg/m2 of cage, or 134 kg/m2 of cage in sum with the realized fish. Up to 93 % of females matured after using of hormonal stimulation. The first female of the triple hybrid sturgeon matured at the age of 9 years, with its body weight of 13.1 kg. Other females became matured in different age, up to 16 years, but ¾ of them were matured at the age of 10–12 years. The maximum registered weight of the triple hybrid female was 29 kg (age 14 years). Inter-spawning intervals for 97 % of females were 1–2 years. Average annual yield of hard roe obtained from one female at the age of 9–16 years was 2.28 kg, average weight of one egg was 17.6 mg, average fecundity was 132 . 103 eggs/female or 7.4 . 103 eggs/kg, average oosomatic index was 12.8 %. These values of production indices for the triple hybrid females are mainly intermediate between the indices of initial species. In 3–4 spawning seasons, the yield of 5.25 kg of hard roe, on average, was harvested from one female of the triple hybrid, or 30 % of its body weight. The yield from the most productive females was 10.8–11.0 kg of roe, or 55–73 % of their body weight. These values are lower than the yeild from amur sturgeon but similar to the yield value for russian-siberian hybrid sturgeon. Caviar manufactured from the roe of triple hybrid sturgeon is distinguished by high quality. Its females are technologically advanced for the eggs harvesting and have a good survival, about 98 % during long-term exploitation. So, the triple hybrid of russian, siberian and amur sturgeon can be recommended for commercial cultivation in warm-water sturgeon farms with intensive harvesting.

TECHNOLOGY FOR PROCESSING OF AQUATIC ORGANISMS,

460-485 693
Abstract
Main technological and chemical characteristics of small-sized shrimps Pandalus borealis, P. goniurus and krill Euphausia superba are presented. The main processes of this kind of shrimp processing are described, with usage of its own complex of proteinases to produce autoproteolysis products. Lysates of these shrimps have high nutritional value comparable with the value of low-fat cottage cheese, though the shrimp lysate protein is a completely animal protein similar to beef one. As a source of low-fat protein, the shrimp lysates belong to the category of specialized and functional food and food ingredients; they also can de considered as the source of omega-3 fatty acids and astaxanthin. Volatile components of the shrimp lysates contain 30 compounds responsible for taste and aroma properties of crabs and shrimps, as thiran, methylthiran, dimethyldisulfide, thioacetic acid, 2-mercaptopropanoic acid, etc. Safety of shrimps and their lysates is provided by low content of organochlorine compounds, radionuclides, toxic elements and low values of microbiological parameters, below of the maximum permissible levels. The shrimp lysates are suitable for using in manufacture of emulsion and pasty products with high commodity properties, classified as gastronomic products with high taste and nutritional value.
486-495 571
Abstract
Results of studies on technology of natural canned meat of ringed seal (akiba) are presented. The frozen seal meat was used for canning without subcutaneous fat that was removed after slaughter. Protein content in the muscle tissue was 22.50 ± 0.71 %, fat content — 8.20 ± 0.20 %, minerals — 1.20 ± 0.10 %, its energy value was 167.4 ± 5.6 kcal/100 g. After defrosting, pieces of the seal meat were kept in fresh water at temperature of 15–18 oC for 2 to 3 hours, then onion and flavorings were added. The spiced meet was packed to cans № 6 and sterilized under temperature of 120 oC. The finished canned food had a meaty taste and smell, without extraneous smacks and smells. The broth was transparent with brown tint and small amount of suspended protein substances. Protein content in the finished canned food was 17.0 %, fat content 7.0 %, protein composition was close to the standard protein by amount and ratio of essential amino acids. Monounsaturated fatty acids dominated in lipids of the canned food (58.08 % of total lipids), mainly oleic (18:1 n-9) and palmitooleic (16:1 n-7) acids; portion of polyunsaturated fatty acids was 22.17 %, including omega-3 fatty acids (18.56 % of PUFA). High content of iron (6.6 mg/100 g), zinc (2.3 mg/100 g) and selenium (80 μg/100 g) was detected in the canned food that partially or completely maintained daily requirements of human body for these elements.


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ISSN 1606-9919 (Print)
ISSN 2658-5510 (Online)