Stock abundance dynamics of sockeye salmon, pink salmon, chum salmon and coho salmon for the last 37 years was analyzed in the rivers Nalycheva, Ostrovnaya and Vakhil. Biological characteristics of spawners (including Chinook salmon) were analyzed in Nalycheva River, and a comparison to Ostrovnaya River was made for the first time (on the data about Nalycheva for 2017). Temporal groups were revealed for all salmon species (in exception of Chinook salmon) in the Nalycheva, and biological differences are demonstrated in case of occurence. Spatial and temporal diversity of Pacific salmon in each of the rivers mentioned was evaluated, and it is concluded, that urgent measures are required to protect salmon stocks in the rivers Nalycheva and Ostrovnaya were made.

One of possible model approuches to the stock abundance assessment of marine commercial shellfish species (crabs) based on the model of the dynamics of three functional groups of the CSA type is discussed in this article. Evaluations of the population indexes are derived from the term of the best similarity of the model to observed data according to the assumptions about the error distribution. As an example, we considered the use of the approuch to the stock abundance assessment of Tanner crab in the Kamchatka-Kurile commercial fishery subzone.

Effects of consumed forage on the changes of gonad indices and reproductive behavior ofStrongylocentrotus polyacanthusin Avachinskaya Bay (South-East Kamchatka) were studied for the first time. The work was accomplished on four stations. It was demonstrated, that intense gamete maturation and high values of gonad indices in the sea urchins colonies in vicinity of Mayachniy Cape was result of feeding on the brown seaweeds Agarum clathrusand Alaria marginata,near the Bezymyannaya Bay — on the macrophyte representatives of Phaeophyceae (Laminaria longipes). Feeding on the other than regular forage organisms (silt, detritus, fragments of crustaceans, calcareous fragments) in the sites where the sea urchins live can cause slowing production of gametes and decrease of the gonad index as a result. S. polyacanthusfrom the colonies situated among the macrophites Rhodophyta demonstrated lower gonad indices, but any changes in the dynamics of forming their gametes have not been observed. In favourable biotopes in vicinity of Mayachniy Cape and Bezymyannaya Bay the sea urchins demonstrated gonad development in May and June for spawning in August.

Analysis of the benthos samples collected in 2005 and 2001 in the Anadyrsky and Mechigmensky gulfs and of the gray whale stomach food lump samples for 2007–2009 has revealed 142 species of amphipods, representing 65 genera, 25 families and two suborders. The benthos fauna of these gulfs, taking into account data from literature, may include 150 amphipod species, including Dyopedos spinosus(?) (Stephensen, 1944), Anonyx robustusGurjanova, 1962, Pseudoanonyx caecusKudrjaschov, 1965, Boeckosimus normani(G. Sars, 1895), Boeckosimus simus (Gurjanova,  1962), Lepidepecreum kasatka Gurjanova,  1962, Aceroides kobjakovae Bulycheva, 1952, Arrhis luthkeiGurjanova, 1936, Monoculodes diamesus (Gurjanova, 1936), Monoculodes semenoviGurjanova, 1938, Westwoodilla coecula(?) (Date, 1856), Pardalisca tenuipesG. Sars, 1893, Stenula arctica(?) Gurjanova, 1951, Caprella longicirrata Vassilenko, 1974 registered in Bering Sea for the first time. A number of taxonomic units identified as “sp.” are most likely new species; three species from the families Phoxocephalidae, Stenothoidae and Pardaliscidaerepresent genera never observed in Russian waters before.
The sublittoral zone of the Anadyrsky and Mechigmensky gulfs is inhabited by predominant cold-waters species of the boreal-polar complex, and the littoral zone – by endemics of the Pacific boreal region.

Distribution of amphipod biomass and population density is demonstrated for the Anadyrsky and Mechigmensky gulfs of the Bering Sea. Sampling (81 quantitative samples) at 47 benthic stations within the Anadyrsky Gulf was made at the depths 19–190 m in August–October of 2005. Sampling (24 samples) from 12 stations within the Mechigmensky Gulf was carried out at the depths 20–45 m in October of 2001. Within the Anadyrsky Gulf the biomass of amphipods varied between several 100th of gram and 6.9 g/m2, the population density – between 2 and 436 individuals/m2. The biomass was 0.8 ± 0.2 g/m2 and population density was 50.3 ± 12.5 individuals/m2 averaged. For the majority of the water area of the gulf the biomass was not over 1 g/m2, and the population density – 10–50 individuals/m2. Within the Mechigmensky Gulf the amphipod biomass was as 10 times as higher, and varied from 0.8 to 70.2 g/m2, it being 20.1 ± 6.6 g/m2
averaged. The population density also was higher – from 36 to 3086 individuals/m2, 527.3 ± 241.3 individuals/m2 averaged.

Based on the results of plankton surveys in 2012–2013, analysis of qualitative composition of phytoplankton was made and description of structural specifics and seasonal dynamics of quantitative indices was provided for the Ptichye Lake of a lagoon type (Southern Sakhalin), having no permanent water exchange with the sea. There were 223 microalgae species and intraspecific taxa revealed, where diatoms predominate (119). The density  of  the  phytoplankton  varied  from  0.04  to  1590.47  thous.  cells/l,  and  the  biomass  –  from  0.005  to 37 609.811 mg/m3. Spring, summer and autumn peaks of phytoplankton density and biomass have been observed.

Possibility of the commercial aquaculture of Pacific mussel in Severnaya Bay of Slavyanka Gulf is analyzed. Periods of spawning and setting traps to collect spate, size composition and survival rate were figured out. The area of the Severnaya Bay is found promising to grow commercial mussels there.