Vol 49, No 2 (2023)

The discovery of new occurrences of pogonophores Siboglinum sp. and Nereilinum sp. from the St. Anna Trough (northwestern portion of the Kara Sea) has been described in this paper. Previously, occurrences of pogonophores (Crispabrachia yenisey and Galathealinum karaense) were reported in the southern part of the Kara Sea, in the estuary of the Yenisei River. Two areas in the Kara Sea where pogonophores were found coincide with the regions of distribution of two types of gas hydrates: oceanic seafloor gas hydrates, and gas hydrates associated with permafrost. Gas hydrate deposits in the permafrost are confined to the coastal regions of the Kara Sea. A methane flux forms in areas of dissociation of gas hydrates under the influence of river runoff. This methane source is vital for the survival of pogonophores. The existence of pogonophores in the St. Anna Trough indicates the presence of a methane flux associated with the inflow of Atlantic water, which causes dissociation of seafloor gas hydrates. The possible role of Arctic warming is apparent in both processes.

A comparative analysis of body shape was performed on 841 specimens of anchovy collected from 21 catches from the Sea of Azov, the Kerch Strait, and the Black Sea off the Crimea and the northeastern coast of the Caucasus in 2006–2007 and 2016–2017. Twenty-three measurements between 12 homologous landmarks of the body of each specimen according to the “Truss Network System” served as characters for analysis. Fifteen characters showed significant differences between the Azov anchovy Engraulis encrasicolus maeoticus Pusa-nov, 1926 and the Black Sea anchovy E. encrasicolus ponticus Alexandrov, 1927. Specimens of the Azov subspecies had larger relative values for all characters of the head region, the height of the trunk region, the re-lative length of the bases of the dorsal and anal fins, and the height of the base of the caudal fin. Specimens of the Black Sea subspecies had a greater postdorsal length and a larger distance from the end of the dorsal fin base to the end of the anal fin base. A multivariate principal component analysis revealed the highest variabi-lity of characters of body height, which depends on the fatness of the fish and demonstrates seasonal dyna-mics. The second group combines characters that do not have a seasonal component (dimensions of the head region, lengths of the bases of the dorsal and anal fins, and postdorsal distance) and can be used for distinguishing the shape of the Azov and Black Sea anchovies. The success rate of classification of Azov and Black Sea anchovies according to the body shape measurement characters using the discriminant analysis was 83.4%.

The cellular composition of the hemolymph of the mussel Crenomytilus grayanus is represented by hemoblasts, hyalinocytes, basophilic, neutrophilic and acidophilic granulocytes with a significant predominance of the latter. With the age of the mollusk, the average values of the size and granularity of hemocytes increased due to accumulation of granulocytes in the hemolymph (up to 100% of all cells) and their mature highly differentiated acidophilic forms (up to 99% of all cells); this indicates a decrease in the rate of renewal of the cell population. During the autumn period of sexual inertia, the number of cells in the hemolymph of mussels decreased with increasing age of mollusks but without any correlation with the shell size. However, in summer, during the spawning period, the concentration of hemocytes either did not change or increased with increasing body size, directly correlating with the number of young basophilic granulocytes. This correlation may indicate either a relationship between the number of hemocytes and the ability of mussels to reach large sizes, or a higher potency in aged mussels for emergency mobilization of the immune system in the summer season through rapid replenishment of the pool of circulating cells with subsequent redistribution of young and mature cell forms between hemolymph and the internal organs.

The genetic variability of the mitochondrial genes COI and cytb was studied in specimens of the big-scaled redfin Tribolodon hakonensis (Günther, 1877) and the small-scaled redfin Tribolodon brandtii (Dybowski, 1872) collected off the coast of Sakhalin Island and the mainland coast of the Sea of Japan. The fragments of the mitochondrial genomes of these taxa are compared to data obtained for the Sakhalin taimen Parahuсho perryi (Brevoort, 1856) and chum salmon Oncorhynchus keta (Walbaum, 1792) from similar habitats. A comparative analysis of intraspecific mtDNA indicate that the formation of mtDNA lineages in four species of fish are associated with paleoclimatic changes in the northwestern Pacific region during the Pleistocene and are largely synchronous. In many instances, the calculated time of divergent evolution of mtDNA genealogical lineages coincide, which suggests the influence of similar evolutionary factors on the studied species.

For the first time, we report the finding of egg masses and an egg-guarding male of the whip sculpin Gymnocanthus intermedius (Temminck et Schlegel, 1843) in Peter the Great Bay (Sea of Japan). Bottom eggs were found in the post-wintering period during a scuba dive at a depth of 12 m. Exact data on the depth of occurrence and structure of the egg masses, the number of eggs per mass, and the sex of the guarding parent fish are provided. Egg characteristics and the substrate, on which the egg masses were laid, are described. The diagnostic features of the male that allowed it to be assigned to G. intermedius are given.