Vol 42, No 2 (2016)

Models that describe the age distributions of fish in catches are discussed. On the logarithmic scale of the Y-axis, the right (descending) part of these curves can be straight or can have an upward or downward concavity, as well as a sharp bend in the middle. These properties of the curves can be explained by variations in the intensity of mortality between different age groups or by demographic variations in the super-population systems. Illustrations of a catch using age curves are provided.

This study was carried out in southwestern Caspian Sea coastal area to elucidate demersal bony fishes distribution and abundance. Twenty two species were found in shore line, which belong to 6 families. In deeper waters down to 7 meters only 5 species of Gobiidae and 1 species of Syngnathidae were identified. Two species Neogobius caspius and N. pallasi were the main components of demersal fishes; however in some regions Rutilus caspicus, Rutilus kutum and Liza spp. were dominated. Most places were dominantly occupied by Atherina boyeri, which had the highest abundance among the pelagic fishes. Conversely, the Ponticola gorlap, N. melanostomus and Proterorhinus nasalis showed the lowest abundances (less than 1 ind./100 m²). Benthophilus stellatus and P. nasali had the lowest niche overlaps with other species. Both of these two species and P. gorlap are suggested to be classified as endangered or vulnerable species based on their low abundance. The distribution of Syngnathus abaster depends on algae, while algae grow up into the stony construction of the coastal line. A negative insignificant correlation was observed between pelagic and demersal fish abundances. The commercial fisheries data of 76 beach seines in our study area during 2002–2013 was compared with our results on fish abundance and species composition. More than 93% of total fish catch constituted Liza spp. and Rutilus kutum. The relationship between the abundance and distribution of the studied species, and the restocking activities performed by Iranian fisheries organization are discussed. The high abundance and distribution of small size fish in tidal zone could be related to the distribution of crustacean, which provide a good source of food for these fish species.

Monitoring of the Black Sea algal viruses in Sevastopol bays and Crimean water areas has been carried out since 2002. Based on the methods that were developed and patented by the author, more than 200 strains of algal viruses of five species of microalgae that are new to science were isolated: TvV (Tetraselmis viridis virus), DvV (Dunaliella viridis virus), PtV (Phaeodactylum tricornutum virus), PpV (Prorocentrum pusillum virus) and IgV (Isochrysis galbana virus). For the first time in the Black Sea, the Emiliania huxleyi virus (EhV) of microalgae was isolated. Using the method of electron microscopy, the Black Sea algal viruses were identified as icosahedral virions with respective sizes of 56–60, 45–48, 50–53, 88–92, and 128–132 nm, for the TvV, PtV, DvV, PpV and IgV viruses. The EhV size, as determined by the method of filtration, was within the range of 50–200 nm. In the IgV and EhV viruses we revealed a viral envelope. Based on their characters the isolated algal viruses were attributed to the Phycodnaeviridae. The maximum number of algal viruses was observed in the spring and autumn seasons, which is typical for their host phytoplankton species. The Black Sea algal viruses, TvV, PpV, IgV, and EhV, displayed no strict species specificity and have a wide range of available hosts.

Phoronida is a phylum of marine invertebrates; they have a worldwide distribution and form huge benthic aggregations in some areas. The taxonomy of Phoronida remains very poorly developed; only 13 species of phoronids have been described worldwide, while approximately 40 varieties of competent larvae are known. Morphological description of phoronid larvae and the search for correspondence between the larval and adult forms make an important contribution to the taxonomy of this enigmatic group. We present an original description of the larval forms of Phoronis australis Haswell, 1883. The larvae and adults of P. australis were collected in the plankton of Nha Trang Bay in the South China Sea. For the first time, the external morphology of larval forms of P. australis was described at the stages of 4, 8, and 20 tentacles. The basic distinguishing features of Phoronis australis larvae were determined: opaque integuments, the presence of a characteristic dark pigmentation of the oral field epidermis, of the unpaired ventral stomach diverticulum, and more than 20 tentacles in the competent larvae. A molecular-genetic analysis based on comparison of the DNA sequences of the 18S rDNA and 28S rDNA nuclear genes confirmed the identity of the phoronid larvae that were found in the planktonic samples from Nhatrang Bay and adult P. australis that were collected in the same area. The problems of Phoronida taxonomy and correspondence of larval and adult forms can be solved only with a complex approach that involves both morphological and molecular-genetic information.

The ultrastructure of cells that form mesonephros tissues in eight species of bony fish of the Black Sea, Gaidropsarus mediterraneus (L.), Lisa aurata (Risso), Trachurus mediterraneus (Staindachner), Diplodus annularis (L.), Spicara flexuosa (Rafinesque), Gobius niger jozo L., Mullus barbatus ponticus (Essipov) and Scorpaena porcus (L.), was studied. It was shown that the ultrastructure of agranulocytes and rodlet cells in the studied species is similar to that of cells in freshwater bony fish. The differences were observed in the number of ionocyte mitochondria, in the vesicle ultrastructure in the cells with radial vesicle array, and in the ultrastructure of the specific secondary granules of neutrophils and eosinophils.

As a result of the centrifugation of the circulating cells of the starfish Asterias rubens in a discontinuous density gradient of sodium diatrizoate, three cell fractions were separated. Small coelomocytes with a high nuclear–cytoplasmic ratio and the lack of granules prevailed in the upper fraction, coelomocytes with small granules evenly distributed in their cytoplasm dominated in the middle fraction, and large coelomocytes with a high content of large granules and vesicles in the perinuclear space were predominant in the bottom fraction. The coelomocytes of the separated fractions were tested for the production of reactive oxygen species, neutral red uptake, capture and internalization of the labeled bacteria Escherichia coli and Staphylococcus aureus, as well as for lytic activity and expression of the ArC3-like gene, which is a homologue of the C3 component of the mammalian complement cascade. Cells of the upper fraction manifested the most pronounced ability for the expression of the C3 gene homologue in response to stimulation with bacterial lipopolysaccharide. Coelomocytes of the middle fraction were distinguished by a pronounced ability to produce reactive oxygen species and phagocytosis, whereas the cells of the lower fraction had a high level of hemolytic activity and neutral red uptake.

A total of six carotenoids, viz., β-carotene, pectenol A, pectenolone (trans- and cis-isomers), zeaxanthin, diatoxanthin, and alloxanthin, as well as esters of alloand diatoxanthin, have been detected in total carotenoid extracts from the tissues of the bivalve Anadara kagoshimensis (Tokunaga, 1906) using the methods of thin-layer chromatography, high-performance liquid chromatography, mass spectrometry, UV-VIS spectroscopy, and characteristic reactions for the identification of chemical groups. The major group (over 90% of the total carotenoids) is comprised of alloxanthin, pectenolone, and allo- and diatoxanthin esters. Tissues of A. kagoshimensis are typically characterized by cyclic variations in the level of carotenoids over the period from winter to summer, with the maxima in February and June and the minimum in April. The largest contribution to the seasonal carotenoid dynamics is made by the major group of pigments (R² = 0.75–0.99), which depends on the pattern of succession of diatomic microalgae during the annual cycle. The pathways of metabolic transformation of the carotenoids in tissues of this bivalve are discussed.

The white char, Salvelinus albus Glubokovsky, 1977, which was originally described from the Kamchatka River basin, and the white char from Lake Kronotsky, Kamchatka Peninsula, are believed to be identical taxonomically and represent two reproductively isolated populations of the same species. However, the data on their molecular divergence show that they may differ at a higher, probably sub-species, level. This suggests the necessity of deeper complex studies of white char and other closely related char species and forms.

Asymmetrical forelimb use is characteristic of many mammalian species. However, little is known about this phenomenon in cetaceans. We examined the asymmetry in pectoral flipper use by the wild orca Orcinus orca (Linnaeus, 1758). During observations from motor boats in the Avachinskii Bay (East Kamchatka) we recorded the use of flippers in slapping the water by individually identified resident (fish-eating) orcas. The studied individuals mostly used their right flipper. The revealed right-sided bias presumably reflects the pivotal role of the left brain hemisphere in the control of forelimb movements, which is consistent with the data that have been obtained for other cetacean species.