Vol 57, No 6 (2017)

Morphological studies of the big-scale sand smelt from the group Atherina boyeri sensu lato were carried out using the materials of the museum collections from the Mediterranean Sea, the Black Sea, and the Sea of Azov. It has been shown that low-raker sand smelt belonging to the species A. boyeri sensu stricto, and multi-raker sand smelt, referred to the A. mochon species, are differentiated by a complex of morphological features: the number of gill rakers, the shape of scales, the length of the ascending process of praemaxillare, and the shape of the lower margin of maxillare. The key for their identification is presented. It is assumed that A. mochon is not a native Black Sea species but belongs to the invasive species originating from the Mediterranean Sea. The isolation of two cryptic species is discussed. The neotype of A. pontica is designated.

The findings of the silver lightfish Phosichthys argenteus at the Pulkovo Ridge (43°–45° S 155°–160° W) are documented. This is the easternmost margin of the species range in the Pacific Ocean. The morphological characteristics of Ph. argenteus are given with a more detailed description of the axial skeleton of the fish. The topography of homodynamic series of the intermuscular bones is specified, and a complex structure of the urostyle, including three autogenous ural centers, is revealed. The comparative morphological analysis did not show any significant differences between the silver lightfish from different parts of the range (New Zealand, Mill Rise, western coast of South Africa, and eastern coast of South America). It is assumed that Ph. argenteus can serve as an indicator species of the notal zone in the open waters of the South Pacific.

Luciobarbus barbulus (Heckel, 1847), a cyprinid fish of the Persian Gulf basin is re-described. Its identity is discussed and its phylogenetic relationship among the tribe Barbini is reconstructed. Luciobarbus barbulus can be distinguished from its close species, L. pectoralis by having thicker lower lip, stronger last unbranched dorsal fin ray and with stronger serration, longer barbels and posterior barbel passes the middle of the eye (vs. not reaching the middle of the eye in L. pectoralis), confirming the identity of both, as distinct species. Moreover, phylogenetic analysis based on the mtCOI sequences, placed the sequenced L. barbulus in a distinct clade corresponding to the tribe Barbini which includes Aulopyge, Barbus and Luciobarbus (three genera from Eurasia and North of Africa), sister to L. pectoralis from Orontes River with genetic distance of 1.7% applying the Kimura 2 Parameter (K2P) model.

Results of the study of 11 lakes situated in the mountainous part of the Amur River basin are reported. Six fish species, namely, blunt-snouted lenok Brachymystax tumensis, Baikal-Lena grayling Thymallus baicalolenensis, Siberian stone loach Barbatula toni, Lagowski’s minnow Rhynchocypris lagowskii, Czekanowski’s minnow Rh. czekanowskii, and Amur sculpin Cottus szanaga, were found in five lakes. Four species were found in one lake (Lake Pereval’noe, basin of the Amgun’ River), and two species were found in each of the remaining lakes. Lenok and Amur sculpin were the most common species. The fauna of Lake Okonon (basin of the river Zeya) was the most specific and did not have analogs among the lake faunas; Czekanowski’s minnow and Baikal black grayling were found in this lake. The lenok ecotype that formed in the mountain lakes differed from the river lenok in some regards. The potential pathways of formation and protection of mountain lake ichthyocenoses of the Amur basin are discussed.

The spatial distribution of eggs and larvae of the walleye pollock Theragra chalcogramma is considered in respect to dynamics of oceanologic processes, nutrients, chlorophyll а and zooplankton off the northeastern coast of Sakhalin Island in spring 2012. It is shown that the effect of severe temperature regime in the near-bottom horizons in the western Sea of Okhotsk during the spawning period of walleye pollock becomes milder due to specific features of water dynamics. The egg distribution is determined by mesoscale eddies in the region. The species survival depends on the effect of such environmental factors as freshwater discharge from the Amur River, eddy structure in waters of the Sea of Okhotsk, and dynamics of phytoplankton and zooplankton development.

In the laboratory experiment and in fish caught in conditionally clean and polluted areas, the presence of metabolites of polycyclic aromatic hydrocarbons in bile by methods of conventional and synchronous spectrofluorimetry was determined. The study showed that this approach is well suited for the detection of metabolites of polycyclic aromatic hydrocarbons with 2–3, 4, and 5–6 aromatic rings. If the content of metabolites of polycyclic aromatic hydrocarbons with 4 and 5–6 rings in bile is low, the method of synchronous spectrofluorimetry is less sensitive than conventional spectrofluorimetry. Both methods of monitoring are simple and fast and reflect the real picture of water pollution.

Using scanning electron microscopy, the main structures of the surface sculpture of scales of mature wild and hatchery fishes and hatchery yearlings of chum salmon Oncorhynchus keta from Kamchatka water bodies are examined and described.

The effect of the prelethal state on functional properties of hemoglobin has been studied in the goldfish Carassius auratus. A considerable decrease in hemoglobin affinity for oxygen and the Bohr effect values and the change in the shape of the curve of oxygen equilibrium have been detected. Such state may be compared to the effect of strong short-term stress.