Vol 43, No 6 (2017)

The structure and seasonal dynamics of marine algal communities dominated by Cystoseira crinita Duby, 1830 were studied in the northeastern Black Sea at depths of 2, 5, and 10 m. Seasonal fluctuations were found to be mainly manifested in biomass changes of the dominant species C. crinita at depths of 2 and 5 m. No seasonal changes in the studied parameters of communities were found at a depth of 10 m. The mean annual production of C. crinita was 1472.3 g/m², with the maximum at a depth of 5 m (2148.1 g/m²). The minimum production was observed at a depth of 10 m. At all depths, the production of C. crinita was highest in the spring; this index had zero values in the fall and winter.

Two smelt species that inhabit the northwest of the Sea of Japan, Hypomesus japonicus and H. nipponensis (family Osmeridae), which are both currently referred to as Japanese smelt, have been studied in order to clarify the taxonomic value of morphometric characters. Variations between individuals of these species have been revealed using a multivariate analysis of their morphometric characters and indices. The results of the analysis show that H. japonicus is distinguished from H. nipponensis both by the previously known characters (the eye diameter is smaller and the vertical through the beginning of the dorsal fin is closer to the head than that through the beginning of the pelvic fins) and by a greater height of the dorsal and adipose fins in the former species as defined in the paper. Within the species H. japonicus, the individuals sampled from Olga Bay are most similar morphologically to those from the coastal waters off the village of Terney. In contrast, the individuals of this species from the coastal waters off Russky Island and from Olga Bay manifest the greatest differences.

Echiurida is a small group of marine benthic invertebrates that burrow in sediments and live a hidden lifestyle. Investigation of the morphology and anatomical features of various organ systems allows better understanding of the biology of these enigmatic animals, many of which are deep-sea species. The morphology and microscopic anatomy of the deep-sea echiurid Protobonellia zenkevitchi Murina, 1976 have been studied using the light microscopy and histology methods. The body of P. zenkevitchi is divided into a proboscis and trunk. The ciliary grooves and large vacuolated cells in the connective tissue of the distal part of the proboscis suggest a specific position of the proboscis on the sediment surface and a mechanism for sorting food particles. It has been shown for the first time that the coelom is not subdivided into compartments. In the digestive tract, an unusual part of the midgut has been found that was previously unknown in echiurids; it probably performs the function of food storage. This part contributes to thorough food digestion, which is important in the oligotrophic conditions of greater depths. The circulatory system of P. zenkevitchi lacks the neuro-intestinal and ring blood vessels. The oocyte storage chamber of the gonoduct has a pore, which apparently connects its cavity with the trunk coelom, but lacks a specialized and well-expressed part, the androecium. A comparative analysis of the microscopic anatomy shows that many organ systems (muscular, coelomic, circulatory, excretory, and reproductive) in P. zenkevitchi have a simpler organization compared to those in other echiurids. This can probably be explained by the small body size of P. zenkevitchi and the great depths of its habitat. At the same time, P. zenkevitchi possesses some unique anatomical characteristics related to the features of the biology of this deep-sea species.

A study of epibiosis of the brown alga Costaria costata in the sublittoral zone of Vostok Bay, Sea of Japan during the spring and summer of 2016 showed that hermit crabs of the following four species accounted for approximately 85% of the total biomass: Pagurus proximus, P. minutus, P. brachiomastus, and P. middendorffii. Of these, the most abundant one (96.5% of the total number of hermit crabs) was P. proximus, the mean aggregation density of which on C. costata (429 ± 221 ind./m²) was higher by an order of magnitude than that in the adjacent area of the bouldery bottom. The size ranges of males and females of this species in aggregations on boulders and those on C. costata were similar, with a predominance of larger individuals on algae. In the size–frequency distribution, three groups of individuals corresponding to three size–age cohorts were differentiated. The male-to-female ratio was 1 : 1.7. Hermit crab aggregations on C. costata are ephemeral; their existence is determined by the duration of the period of algae development, that is, from late spring to the middle of the summer.

Wax esters, which are esters of fatty alcohols and fatty acids (FAs), are one of the main classes of reserve lipids in all coral species. The chemical structures and the content of wax ester molecular species were determined for the first time in nine coral species from three taxonomic groups: symbiotic reef-building corals, (Hexacorallia subclasses), symbiotic soft coral alcyonarians, and asymbiotic soft coral gorgonians (Octocorallia subclasses) collected in the South China Sea (Vietnam). Our comparison of these groups showed that the absence of symbiotic microalgae (zooxanthellae) and the exoskeleton affects the profile of molecular species of wax esters considerably. The main components of wax esters of all corals were cetyl palmitate (16:0-16:0) and other saturated wax esters containing 30, 34, and 36 carbon atoms. The content of unsaturated molecular species 6:0–16:1, 16:0–18:1, and 16:0–20:1 in wax esters of symbiotic soft corals (alcyonarians) was greater than that in wax esters of reef-building corals. In contrast to symbiotic coral species, wax esters of asymbiotic soft corals, namely azooxanthellate gorgonians, contained a considerable amount of long-chain molecular species (C₃₇-C₄₁) with an odd number of carbon atoms. The presence of such molecular species indicates that asymbiotic gorgonians may use bacterial FAs in biosynthesis of their own wax esters. This observation confirms our hypothesis that bacterial community is important for maintaining the energy balance of azooxanthellate corals.

Serological detection of some pathogens in the beluga whale Delphinapterus leucas population from Sakhalinsky Bay of the Sea of Okhotsk (Sakhalin–Amur beluga whale stock) was performed in 2013–2014 after the largest recorded flood of the Amur River (among observations since 1896). The percent of this population that is immune to the causative agents of clonorchosis was 25.6%; toxoplasmosis, 11.5%; brucellosis, 38.5%; tuberculosis, 30.8%; cetacean morbillivirus infection, 16.7%; and to alpha and gamma herpes viruses each, 21.8%.

As a result of observations conducted in Magadan in the summer of 2016, a hybrid Glaucouswinged × slaty-backed gull pair has been described as nesting in an anthropogenic landscape for the first time.

We tested the locus of the nuclear lactate dehydrogenase gene (LDH-C1) as a phylogenetic marker in specimens of 11 salmonid genera (Thymallus, Coregonus, Hucho, Brachymystax, Salmo, Salmothymus, Acantholingua, Parahucho, Salvelinus, Parasalmo, and Oncorhynchus). All the sequences were veraciously clustered according to their taxonomic affiliation at the species and genus levels. It is shown that used complex of characters contains a phylogenetic signal that represents specific information about the phylogenesis process. This allows us to recommend the LDH-C1 locus to specify the phylogeny of salmonids in the combined analysis of several independent nuclear genes and mitochondrial DNA.