Vol 49, No 1 (2023)

A comparative study of some parameters of nonspecific immunity in sexually mature individuals of pink salmon and chum salmon caught on June 6–July 1, 2018 by an epipelagic trawl in the open waters of the northwestern part of the Pacific Ocean was carried out. The level of antimicrobial properties of blood serum and nonspecific immune complexes in the tissues of the kidney, spleen and liver and the proportion of immunodeficient individuals were studied. Significant differences in the antimicrobial properties of blood serum and immunodeficient individuals were found. These differences are probably due to species characteristics, as well as the pre-spawning period of the annual cycle in pink salmon.

The effect of 30-day starvation on the state of the antioxidant complex and lipid peroxidation in the tissues of the Black Sea bivalve mollusks Anadara kagoshimensis (Tokunaga, 1906) was studied. Mollusks were collec-ted on a mussel and oyster farm near the village Katsiveli (the Southern coast of Crimea, the Black Sea) on April 2020. The mollusks were kept in aquariums with a closed water exchange system with biofiltration of water. The mollusks of the experimental group were not fed for 30 days. The activity of glutathione peroxidase, glutathione reductase, superoxide dismutase, catalase, the content of reduced glutathione and TBA-reactive products were determined. It was found that under fasting conditions the content of TBA-reactive products decreased in the hepatopancreas and the foot of the mollusk, and did not change in the gills. The most pronounced changes in the AO complex – an increase in all the studied parameters – were detected in the hepatopancreas. An increase only in the parameters of the antioxidant glutathione system was found in the foot, and an increase only in the activity of glutathione peroxidase and in the content of reduced glutathione was found in the gills. The results obtained in the study have shown a stable antioxidant-prooxidant ba-lance in the bivalve mollusk A. kagoshimensis under starvation conditions.

In the present study, using the Farm Aquaculture Resource Management (FARM), farm aquaculture resource management model, we calculated the potential productivity of plantations of the oyster Magallana gigas (Thunberg, 1793) (Bivalvia: Ostreidae) in Voevoda Bay (Sea of Japan, Peter the Great Bay, Russkiy Island). When calculating the productivity of cage and bottom plantations of M. gigas, we used the previously obtained results of numerical modeling of bay’s dynamics of hydrological parameters using the open software Delft3D-Flow, taking into account the inflow of fresh water into the bay in 1990–2019. To demonstrate the heterogeneity of growing conditions for M. gigas, three sites 100 × 100 m in size were selected, located in Kruglaya and Melkovodnaya Bays, as well as in the central part of Voevoda Bay. For each plot, modeling of 28 growing periods, lasting 22 months each was performed. The maximum values of oyster yield for the se-cond year of cultivation, expressed in tons of total wet weight, were selected, and distribution histograms for each area were presented. It was shown that, according to hydrological and biological indicators, the growing conditions even in small Voevoda bay are heterogeneous. It has been established that the variability in the productivity of M. gigas is associated mainly with the extreme uneven redistribution of primary production in Voevoda bay under the influence of hydrodynamic factors.

Our studies were carried out in July 2016, in the Uda Bay and the Academy Bay (including the Ulban Bay and Nikolay Bay). The primary production (PP) of phytoplankton in the photic zone was calculated from the thickness of the euphotic zone, as well as by the concentration of chlorophyll а, and the assimilation numbers of phytoplankton. We used for calculations a modified nonrectangular hyperbola model, for photosynthetic light-response curves of phytoplankton. The formation of PP is a function of the supply of nutrients to the photic zone from the underlying waters by intense tidal currents under conditions of weak stratification. The high concentrations of humus substances in Uda Bay limited the growth of phytoplankton. The values of integra-ted PP varied between Uda Bay to Academy Bay from 250–1000 to 1069–4268 mgC m^–2 day^–1.