A new system of views on effective management in fisheries has been developed by fishery science in the beginning of the 21^st century under the aegis of FAO (UN). It claims the principle of ecosystem approach in fishery studies. However, this approach is still not realized. Uncertainty of ecosystems behavior is the main problem that impedes coordination of fish- eries with functioning of the ecosystems. The problem could be solved with comprehensive investigation of all elements and structure of ecosystems and their modeling that, in turn, is impracticable without continuous monitoring of their state in complex marine surveys. In the Russian fishery science, too, the single-species approach still prevails in the resource assess- ment, estimation of total allowable catch (TAC) and acceptable biological catch (ABC), and prospective fishery forecasting instead of multi-species approach and ecosystem allowable catches (EAC). Management of fishery is still based on optimization of commercial stock by means of various measures of fisheries regulation. Insolvency of the Concept of development of fishery science in the Russian Federation till 2020 is discussed. Efforts of the TINRO-center on introduction of ecosystem approach in practice of fishery studies are noted.

Population structure of Asian sockeye salmon is considered by variability of 45 loci of single nucleotide polymorphism DNA (SNP) in 17 samples from its 10 major spawning grounds at Chukotka, Kamchatka, and northwestern coast of the Okhotsk Sea. General pattern of genetic heterogeneity of sockeye salmon is well corresponded with spatial-geographic structure of the species. Five groups of populations are determined by cluster analysis and AMOVA: the so called nuclear populations at Kamchatka, as the population complexes of the Ozernaja River and Kamchatka River, the group of secondary stocks of the lake-river systems at Koryak coast, and two subperipheral populations of Chukotka and the Okhota and Palana Rivers. The groups split to the south and north complexes. Possible mechanisms of such differentiation with close similarity among populations of South-East Kamchatka and strongly separate population of the Palana and Okhota Rivers are discussed taking into account other markers (microsatellite loci, mtDNA). There is supposed that high differentiation of the Palana and Okhota River sockeye is caused by mutual impact of adaptive (local selection) and demographic (gene drift, effective number decrease) processes in this population.

Walleye pollock maturing, its gonads changes and the oocytes development are considered, in particular the structure of filiform gonads, gonads of hermaphrodites, and atretic phenomena. Determining of the maturity stages is discussed, with some recommendations. The first stages (I, II) are usually determined without any problem. Gonad color is recommended to be accounted for correct determining of the stage II-III, it becomes more saturated and reddish at this stage. The stages III and III-IV could be combined, so far as they have no any cardinal difference. Special stage VI-III is proposed for re-spawning fish because of more viable eggs. Distinctive features between the stages IV-V and V are described. Deviations in gonad development are noted, as resorrption, filiform gonads, or hermaphroditism that are important bioindicators of the populations state and their living conditions. Year-to-year variability of these deviations frequency is shown. Three types of the filiform gonads are defined, containing whether male or female germ cells or connective tissue. The true synchronous type of hermaphroditism is determined for pollock.

Some biological parameters of chum salmon in the spawning runs to the Paratunka River (Avachinsky Bay, Kamchatka) are analyzed on the materials of ichthyological researches conducted in 2010-2015 (3699 specimens sampled), observations on filling of the spawning grounds, and fishery statistics. The age at return is defined using scale samples and the age structure of the spawning run both for wild and hatchery populations. The fish origin is determined by the scale circuli patterns in the zone representing the juvenile period, comparing the scale samples from natural spawning grounds and hatchery weir. Accuracy of this method is estimated in 82-99 %. Abundance of the spawners had the increasing tendency since 2009. Three runs with different age structure and size of the fish were observed in the lower river: in early summer, late summer, and fall. The elder wild chum ran to spawning while the body length, weight and fecundity were similar for both stocks. The hatchery stock had higher male : female ratio. Survival of the wild fish from egg to the return was estimated as 0.67 %, and of the hatchery fish as 0.28 %. Portion of the hatchery fish was 44-48 % at the Paratunka mouth and 25-35 % on the spawning grounds, whereas it was 70-83 % at the hatchery. The chum salmons’ straying to certain loci of the river basin is determined.

Recently the sea ice edge at Chukotka retreats further northward in summer and new ice formation begins in a month later in autumn than in previous decades because of climate change that changes the pacific walrus Odobenus rosmarus divergens habitat. Now the Bering Sea becomes completely clear of the ice by start of the spring migration of walruses. In these conditions, the walrus migration routes and feeding grounds location changes. Permanent walrus rookeries on the eastern coast of Chukotka and Kamchatka disappeared (Verkhoturov Island, Karaginsky Island, Bogoslov Islands, Anastasia Bay, Cape Dezhnev, Cape Sery, Cape Olutorsky, Cape Zosima) and new rookeries have formed in the Bering Sea (at Meinypylgino and Enmelen) and on the Arctic shore of Chukotka (at Vankaren and Cape Shmidt). Benthos community has changed, too. As the result, quality of the walrus habitat became worse, the sickness and mortality of young animals increased and the reproduction rate decreased. Formerly stable large walrus rookery in the Krest Bay (Meeskyn) was surveyed in 2016. Together with Retkyn rookery in the Rudder Bay it formed the large Anadyr group of walruses, about 50,000 of the animals gathered on these rookeries in the 1980s. However, the group began to fluctuate with decreasing trend since the 1990s: its number was estimated as 5,000-6,000 animals in 1996, 12,000 in 1997, 30,000 in 1999, 26,000 in 2000, 6,000-8,000 in 2001-2007, 2,000 in 2008. Meeskyn rookery did not function since 2006, though small group of 200 animals was observed here in 2016. Two hypotheses on this tendency are proposed: i) negative influence of climate change on reproduction of walruses in the Chukchi Sea; ii) depletion of the walrus feeding grounds in the Anadyr Bay caused by climate change and excessive abundance of the population.

Sex and age structure of pacific walruses on the shore rookeries at Cape Serdtse-Kamen’ is considered on the data of observations in 2009-2014. In total, sex and age were determined for 13766 walruses. Adult females were the largest sex-age group - 42.95 %, adult males were 21.48 %, young animals of 3-5 years old - 12.73 %, yearlings (1-) - 12.31 %, calves in the age 1+ - 5.95 %, and calves 2+ - 4.58 %. The portion of parous females was 28.67 % of the total number of mature females that is a sign of low population replenishment. Mortality rate of walruses in the first three years of their life is estimated. Taking into account that up to 80 % of the population was concentrated in the area of observations, the data represent authentically the current status of the pacific walrus population.

There is determined for barfin plaice Liopsetta pinnifasciata that individual and age variability of its eggs diameter is poorly expressed, relative fecundity has no age variability, individual fertility increases with age (from 53,000 to 730,000 eggs) proportionally to the gonads growth, males mature faster and reach puberty in the main in the first year of their life (percentage of spawning males/females is 68/12 in the age of 1 year, 100/31 in the age of 2 years, 100/45 in the age of 3 years, and only in the age of 4 years all females spawn), but females have longer life span and the females only are presented in the age 6+ and older, for the most part they live up to 10 years, reaching the length of 39 cm, and the maximal their age is 12 years. So, the males prevail in the younger age groups and the females in the elder age groups; periods of puberty are 7-8 years for females and 4-5 years for males that is 67-89 % of the life span for both sexes. The age groups 3+...6+ make the highest contribution to population fecundity.

Previously, catchabilty of walleye pollock was estimated for the accounting trawl RT/TM 57/360 by results of acoustic measurements of fish density in the towed layer under fishing vessel. However, fish reaction to noise field ahead of vessel was not accounted in that experiment. Besides, distortion of initial distribution of fish by the vessel noise could cause an error in fish stock estimations by methods of echo integration. Data of new experiment conducted for estimation of fish reaction to the vessel noise are presented using independent floating buoy equipped by scientific echo sounder. Distance of walleye pollock reaction to the vessel noise was estimated as 140-180 m that corresponds to the calculated value (150 m) used in modeling. Distortion of typical fish distribution was considerable: the fish density decreased in the upper layer and gradually increased in deeper layers as the fish moved down. The density decreasing in the layer 0-100 m was evaluated as 0.56, i.e. the echo integration method underestimated the fish density on more than 40 %, the decreasing in the layer 100-200 was less significant (0.86). Fish moved down under the noise effect in 10 times faster than at their daily vertical migration. The experimental data on walleye pollock density change under influence of passing fishing vessel are compared with the modeling results. Estimations of catchability coefficient for the accounting trawl РT/TM 57/360 are corrected taking into account the depth of trawling. The corrected coefficients of catchability for walleye pollock vary from 0.01 at the sea surface to 0.85 at the depth equal to the distance of its reaction to the noise.

Taxonomic composition, distribution and resources of the macrobenthos within the depth range of 5-230 m are considered on the materials collected by bottom sampler in the survey conducted in Peter the Great Bay in 2011 (233 stations, 400 samples). The same grid of samplings was used as in the previous survey in 2003. The data were averaged within 5 domains: Amur Bay, Ussuri Bay, the Western (westward from 131^о30′ E), Central (131^о30′-132^о30′ E) and Eastern (eastward from 132^о30′ E) areas. In general, the average total biomass of the macrobenthos in Peter the Great Bay in 2011 was 241.8 ± 21.1 g/m², that is almost the same as in 2003 (265.4 ± 25.1 g/m²). The main taxonomic groups of macrobenthos were: bivalves (34.0 %), polychaetes (23.0 %), phoronids (7.1 %), and barnacles (7.1 %); these 4 groups formed 71.1 % of its total biomass and with other 11 common groups with the portions 11,0-3.5 % each (sea anemones, nemerteans, echiurans, amphipods, gastropods, sea stars, brittle stars, sea urchins, holothurians, ascidians, and algae) - 96.6 % of its total biomass. Relative to 2003, the portion of polychaetes and phoronids became larger (15.8 % and 4.33 % in 2003, respectively), and the portions of holothurians and echiurians became smaller (12.1 % and 7.3 % in 2003, respectively). The value of Shorygin-Shoener similarity index ( I_CS ) of the macrobenthos of Peter the Great Bay was 79.7 % in both 2003 and 2011. Decreasing of bivalves and increasing of polychaetes were observed in all areas of Peter the Great Bay. In the Amur Bay, the mean total biomass and ratio of the dominant groups didn’t change, with exception of some decreasing of bivalves and increasing of polychaetes. In the Ussuri Bay, the mean total biomass and composition of the dominant groups did not change, too, but the portions of holothurians and echiurans decreased significantly and the portions of phoronids increased more than 3-fold. In the Western area, the place of echiurans, which in 2011 were practically not found, was occupied by sea urchins and ascidians, the biomass of brittle stars was 1.5-fold decreased, too, but amphipods became more abundant. In the Central area, the biomass of holothurians decreased in 8 times that caused the 1.7-fold decreasing of the mean total biomass of macrobenthos. In the Eastern area, the most significant changes were the sponges decreasing and almost 2-fold increase of the polychaetes biomass. The total resources of macrobenthos in Peter the Great Bay are assessed in 2011 at 1.5 million tons (340 thousand tons less than in 2003). The gross biomass of bivalve mollusks and polychaetes was estimated at 473 and 404 thousands tons, respectively, or in sum about 60 % of the total biomass of macrobenthos. Between the 2003 and 2011, the following prominent changes of the taxa gross biomass occurred: polychaetes +100^. 10³ t, bivalves -80^. 10³ t, echiurans -100^. 10³ t, and holothurians -400^. 10³ t. Anyway, the dominant taxonomic groups of Peter the Great Bay macrobenthos were constantly bivalves and polychaetes (and barnacles in the Amur Bay) and all changes in taxonomic structure or even replacing each other concerned the subdominant and minor taxa. Reasons of some changes, as significant (dozens of times) decrease in the biomass of holothurians and echiurans (mainly Pentamera calcigera and Echiurus echiurus ) are still vague and possibly are related to biology of these species.

State of plankton community was monitored in the Pacific waters at Kuril Islands in July-August 2016, in conditions of mass feeding migrations of subtropical fish. Structure of the plankton community corresponded to its summer season: the large-sized fraction of zooplankton prevailed by biomass (74-86 %), the portions of medium- and small-sized fractions were 3-13 % and 11-15 %, respectively. The dominant groups in the large-sized fraction were copepods ( Neocalanus plumchrus, Metridia okhotensis, Metridia pacifica, Eucalanus bungii ), arrowworms ( Sagitta elegans ) and hyperiids ( Themisto pacifica ). Copepoda nauplii and copepodites of I-II stage, Euphausiacea furcilia and caliphyptophytes, and juvenile hyperiids were found in the small-sized and medium-sized fractions. Total biomass of the large-sized fraction was significantly higher in summer 2016 than in July-August 2015, obviously because of earlier phase of seasonal succession under colder thermal regime. In 2016, the biomasses of copepods and sagittas were at the mean long-term levels, and the biomass of euphausiids was above the norm. The biomasses of the small- and medium-sized fractions were above the norm, too. The total stock of plankton in the surveyed area in July-August 2016 was assessed in 92926^. 10³ t. High biomass of zooplankton in this area was favorable for feeding of subtropical fish.

Feeding conditions of the main commercial fish species are assessed and their feeding relationships are considered on the materials collected aboard RV Professor Levanidov and RV TINRO in the Pacific waters at Kuril Islands in July-August of 2015 and 2016 in the surveys targeted on evaluation of the subtropical species migrations, as Scomber japonicus, Scomber australasicus, Sardinops melanostictus , and Todatodes pacificus , as well as pre-anadromous migrations of salmons Oncorhynchus gorbusha and Oncorhynchus keta . Copepods, euphausiids, and hyperiids dominated in the diet of subtropical species, with exception of Scomber japonicus and Scomber australasicus with fish as a significant part of the diet and Sardinops melanostictus with phytoplankton in the diet. In the salmons diet, copepods, euphausiids, hyperiids, and pteropods prevailed for pink salmon and euphausiids, pteropods, hyperiids, and medusas for chum salmon. Daily and monthly rations were calculated for fish species and their ratio with the stock of large-sized zooplankton was determined. The main consumers of zooplankton were Scomber japonicus (49 % of total consumption in 2016) and Sardinops melanostictus (40 %) and the main consumers of nekton - Scomber japonicus , too (86 % of total consumption in 2016) and Scomber australasicus (13 %). Salmons consumed no more than 1 % in sum. In 2015, Scomber japonicus also was the main consumer (73-71 % of the total consumption of zooplankton and nekton) and salmons’ consumption was even lower. The stock of zooplankton, being in 18 times larger than the fish biomass, provided full feeding demand of the consumers. The stocks of the preferable preys, as euphausiids, copepods, and amphipods, exceeded their consumption in 15-25 times in 2016, though slight deficit of euphausiids was observed in 2015, compensated by high abundance of copepods, hyperiids, medusas and small-sized nekton.

Two basic types of vertical thermal structure are defined in the North-West Pacific on the data obtained in CTD survey conducted from May 29 to July 9, 2013 . One of them prevailed in the coastal areas of the Bering Sea and at East Kamchatka where the depth of winter convection was 160-200 m and even more. The other extended over the open ocean with lesser depth of convection as 90-130 m. Their difference in the cold subsurface layer thickness is analyzed in relation with temporal variations of the sea surface temperature and wind stress during preceding winter. The wind forcing contributes to deepening of winter convection in the coastal areas because of the shoreward Ekman transport but induces mostly horizontal advection in the open ocean. The wind-driven flows promote additional cooling in the subsurface layer in the western Bering Sea and major part of the NW Pacific, except the Alaska Stream area where they cause a warming in this layer. The warm intermediate layer in the whole region is supported mainly by westward advection of relatively warm water in the Alaska Stream and partially by the compensatory flow from the south that balances the Ekman transport in the upper layers.

Wind regime at the Okhotsk Sea coast is considered on the base of anemometer data obtained by the Hydrometeorological Centre of Russia since early 1970s (vanes were used for the wind rate measurements before). Climatic-scale trends in wind direction and wind rate are revealed for the 43 years period. The wind rate has a tendency to decreasing in all seasons, in spite of seasonal change of the dominant direction, with the regime shift in the late 1980s. However, the main patterns of the atmospheric circulation over the Okhotsk Sea have changed slightly, so the direction of the prevailing winds is rather stable: weakening of the zonal wind component in winter was observed for several stations in the late 1990s - early 2000s only and insignificant weakening of the meridional (south) wind component occurred in summer.

Oceanographic conditions influence on saury fishery in the South-Kuril Region is considered on the SST satellite data and fisheries information obtained in August-November of 2002-2014. The SST spatial distribution patterns are compared between the years with high and low landings of saury and the catch efficiency, taking such parameters as the distance of the South Kuril anticyclone eddy from Shikotan Island and the northern Subarctic Front (NSAF) position as quantitative measures of oceanographic conditions. Three basic types of the patterns are defined: 1) long distance to eddy and southern NSAF position; 2) short distance to eddy and northern NSAF position; and 3) short distance and medium NSAF position. The type 1 was observed in 2002, 2003 and 2009 when stable saury fishery began in late August and continued in September-October within the exclusive economic zone of Russia (EEZ) and in November outside EEZ, with low efficiency (CPUE 14-34 t/day, increasing to November). The type 2 was observed in 2004, 2005, 2007, 2008 and 2014 when stable saury fishery began in early August and continued within EEZ till November, with high efficiency (CPUE 31-43 t/day, with maximum in September). The type 3 was observed in 2006, 2011, 2012 and 2013 when stable saury fishery began in late August and continued within EEZ till October, then gradually moved outside EEZ, with medium efficiency (CPUE 20-36 t/day, with maximum in October).

Species composition of the most common species belonging to the taxa of macrozoobenthos - potential indicators of vulnerable marine ecosystems is considered on the data of bottom-sampler and bottom trawl surveys in the Chukotka and Koryak districts of the Bering Sea. The Chukotka district is mostly shallow-water area (prevailing depths 20-60 m) where these taxa-indicators are: sponges ( Myxilla incrustans , Halichondria panicea , and Semisuberites cribrosa ), barnacles ( Chirona evermanni ), ascidians ( Halocynthia aurantium and Boltenia ovifera ), octocorals ( Gersemia rubiformis ), bryozoans ( Cystisella saccata and Flustra foliacea ), and brittle stars ( Gorgonocephalus eucnemis ). Settlements of immobile sestonophages (the first 5 taxa) occupy mainly the hard or mixed bottom grounds in the coastal zone and movable filtrator (the last taxon) is distributed deeper on loose grounds. The Koryak district is deeper (up to 870 m depth); beyond the abovementioned taxa the other common taxa-indicators here are marine whips ( Halipteris willemoesi ), sea lilies ( Heliometra glacialis ), and sea anemones ( Actinostola callosa ) and 3 more species are common for octocorals ( Anthomastus rylovi, Paragorgia arborea , and Paragorgia sp.). The list of taxa-indicators includes immovable or almost immovable sestonophages (octocorals, sponges, ascidians, bryozoans, barnacles, sea whips, and sea lilies), moving filtrators (brittle stars) and predators (sea anemones). All these taxa could be divided onto 3 groups according to the depth of their occurrence: i) continental shelf residents (barnacles, bryozoans, sea squirts Boltenia ovifera and Gersemia rubiformis ); ii) continental slope residents (octocorals, sea whips and sea lilies); iii) interzonal dwellers (sponges, brittle stars, sea squirt Halocynthia aurantium , and sea anemones). The epibenthos is the most abundant in the area between Cape Navarin and Cape Haidin that obviously is the sign of high bioproductivity of this area. The data of long-term observations confirm high stability of distribution patters and abundance of the epibenthic communities in the western Bering Sea.

Enzymatic processing of laminaria Saccharina japonica by industrial enzymes of proteolytic, mixed and amylolytic (cellulosolytic) action (CelloLux-F, Viscoflu MG, Allzyme РТ, Allzyme Vegpro, and Allzyme BG) is investigated. Alginase activity of enzyme preparations was measured by spectrophotometry with an anthrone reagent. Chemical composition of algae and fodder was determined by standard research methods. Total content of nitrogenous substances in the raw materials was determined by Kjeldahl method on the Kjeltec auto 10 SO Analyzer (Tecator, Japan). Alginic acid content was determined by titration method. Total lipid content was determined by Blight-Dayer method. The content of easily hydrolysable polysaccharides was determined by titration according to Bertrand. In the experiment, CelloLux-F had the highest alginase activity and Allzyme РТ had the lowest activity. Activity of other enzymes lowered in the order: Viscoflu MG > Allzyme BG > Allzyme Vegpro. The alginase activity of enzyme preparations determines their concentrations necessary for hydrolysis. Following to recommendations of the enzyme preparations manufacturers and cited information on their usage, the raw alga materials was processed during 6 hours under pH 6, gm 1 : 10-1 : 12 and temperature 55^оC and 60^оC. Under the processing, the main changes occur in quantitative composition of carbohydrates, namely the alginic acid content is reduced in 17.2-25.3 %, the fiber content is reduced in 38.5-74.0 % and the amount of easily hydrolyzable carbohydrates is increased in 2.7-3.7 times. Degree of the polysaccharides hydrolysis after processing with different enzyme preparations has lowered in the order: Allzyme BG (36.9 %) > CelloLux-F (35.5 %) > Allzyme Vegpro (34.6 %) > Viscoflu MG. The fermented algae were introduced into the mixed fodder formula. Using the processed alga instead of natural one allows to increase the content of easily hydrolyzable polysaccharides and to decrease the content of high-molecular polysaccharides as alginic acid and cellulose. Food efficiency of the mixed fodder was examined by biological testing with using pigmented sea cucumber juveniles with weigh 40-90 mg as the test-objects; the testing was conducted on the basis of aquaculture research complex Zapovednoe in the Kievka Bay (northwestern Japan Sea). The mixed fodder with natural laminaria from the Kiyevka Bay was used as a control in examination. Value of the mixed fodder was estimated by gain in body weight of test-objects. The tests showed the 3-5 times higher gains of the sea cucumber juveniles fed by the mixed fodder with fermented laminaria in compare with the control mixed fodder based on unprocessed algae.

Ability of the bifidobacteria metabolites to break down the sodium alginate molecules is shown for the case of alginate-containing biogel from brown algae with 0.2 % of sodium alginate and the metabolites of bifidobacteria cultured on the semisolid Blaurock media in presence of this biogel. The allocated metabolites caused enzymatic degradation of alginic acids: the lower the alginic acids concentration, the higher the rate of degradation. Effectiveness of the bifidobacteria metabolites to split the sodium alginate depended on stage of the microorganisms development. The samples incubated with metabolites in the stationary phase of growth had viscosity of the polysaccharide solution reduced in 23.0 %, and those incubated in the phase of cell death - in 43.8 %, with the molecular mass of polysaccharide decreased in 1.8-2.0 times. Mechanisms of the sodium alginate utilization by bifidobacteria are discussed.

Chemical composition, content of protein, minerals, free amino acids and fatty acids in the muscles, heart, tongue, kidneys, liver, and lungs of California grey whale Eschrichtius robustus are examined. All eatable parts of the grey whale body are significantly watered (water content 78.5-80.5 %), with the minimum water content in the tongue and the maximum in the kidneys. The meat of grey whale has low lipid content and is similar to low-fat beef, lamb or horsemeat. All essential amino acids are presented in the proteins with slight differences in their content depending on localization. Lysine and leucine have the high level in all eatable parts of the whale (15.3-22.6 mg/g WW). The highest content of polyunsaturated fatty acids is found in the heart (36.49 %). The content of water-soluble protein varies from 17.9 % for the tongue to 57.9 % for the liver, the content of myofibrillar proteins in the meat, kidneys, tongue and heart ranges between 12.8-25.2 % but they are absent in the lungs and liver. Concentration of toxic elements (As and Cd) depends on localization, with the highest level in kidneys: As 0.42-2.80 mg/kg WW, Cd 0.05-1.22 mg/kg WW.

Sea cucumber Apostichopus japonicas is distinguished by high diversity of biologically active substances. Their extraction by honey is one of traditional ways of the sea cucumber using as a therapeutic and prophylactic agent. Mixture of xanthan gum and locust bean gum with apple pectin in different concentrations is used as the honey solvent. Organoleptic properties and viscosity of the compound of sea cucumber mixed with this honey solvent in different proportions are evaluated and their ratio providing uniform and stable consistency with viscosity 3.0-4.5 Pa^.s during long-term storage is chosen as the optimal one. The product heating to 70^оC causes a significant increase in viscosity that can be explained by loss of water from muscular tissue of the sea cucumber and its binding with the structure-forming agent. The heating of the compound with 1 % of xanthan gum causes the viscosity increasing in 4 times as compared with the control sample. The sequence of technological methods for producing the biologically active supplement «Trepang on honey» with stable structure and composition is proposed. The supplement contains 0.3 % of glucosamine and 0.1 % of glycosides. Daily dosage of this supplement is determined.

Methods of SCUBA hydrobiological surveys are discussed on the base of the author’s 18-year experience in the western Tatar Strait (Japan Sea) and in the Okhotsk Sea. Typical errors of the assessments are analyzed. So far as the methods of underwater researches develop actively, there are no universal one in this field. Regular sampling and uniform assessment methods do not guarantee to avoid the errors but usually cause excessive volume of samples and man-hours. Optimal planning of the sampling should be based on statistical analysis of preliminary information about distribution of the assessed objects in the area of survey. Planned number and location of the sections, stations and samples should be adjusted on the spot, if necessary, following the principle of sufficiency for obtaining representative data. The sections should be performed taking into account types of the coast, the stations - in accordance with natural biotic stratification. Sampling tools and methods should be chosen in dependence on nature, size, density, and distribution patterns of the assessed objects and specific conditions of survey. Modern technical means of underwater video surveillance, echolocation and satellite navigation must be involved into practice of SCUBA surveys. Some original sampling tools developed by the author are presented. Their use can significantly reduce the SCUBA man-hours, and in some cases allows to manage without diving. Rational planning and competent conducting multiply effectiveness of SCUBA survey, allowing to reduce its labor and time costs.