P. A. Saveliev

Distribution and some features of the biology of the eelpout Lycodes tanakae Jordan et Thompson, 1914 (Perciformes: Zoarcidae) in the Tatar Strait, Sea of Japan

Based on data from studies that were performed in 2006, 2007, and 2009, we analyzed the distribution and some features of the biology of the eelpout Lycodes tanakae, which inhabits the Tatar Strait. The young of this species (<30 cm in TL) predominantly occur to the north of 50° N. The largest individuals (>71 cm in TL) are found to the south of 49° N and medium-sized fish occur throughout the studied area. In the Tatar Strait, L. tanakae inhabits the 50–615 m depth range, but the majority of the eelpouts (67.9%) were caught from depths of 200–600 m. Small individuals of this species (<30 cm in TL) occur at depths of 50–200 m, while medium-sized and large fish (>30 cm in TL) can be found at all depth horizons that were surveyed. The mean linear size of L. tanakae increases with an increase in the depth of their habitat. The relationship between the spatial distribution of L. tanakae and water temperature regime is discussed. The nutritional spectrum of L. tanakae includes 18 food items, with fish and shrimp predominating. Young L. tanakae (<30 cm in TL) are benthophages, 41–50-cm individuals feed mainly on cephalopods and fish.

Distribution and some traits of biology of Lycodes tanakae (Perciformes: Zoarcidae) in Primor’e waters (Sea of Japan)

With consideration of investigations made in 2004–2010, the spatial distribution of Lycodes tanakae, as well as some traits of its biology in Primor’e waters, is described. This species occurs all over the investigated region—from 42° to 49°N as explained by hydrological properties of bottom waters and by the bottom relief of this water area. In Promor’e waters, Lycodes tanakae occurs at depths of 87–1034 m. However, the majority of specimens (90%) prefers depths of 200–700 m. Thus, it can be attributed to the mesobathial ecological fish group. In spring and summer, juveniles of L. tanakae live at similar depths (200–350 m) where this species seems to spawn. In catches, L. tanakae is represented by specimens 11–90 cm in length, 0.1–4.9 kg in weight, and age from 1 to 10 years. The bulk of catches consists of specimens 40–70 cm long (62%), up to 2.2 kg in weight (90%), and of the age 4–7 years (72%). Sexual dimorphism in linear dimensions is not determined in L. tanakae. In summer, the ration of L. tanakae in Primor’e waters consists predominantly of cephalopods (on average, 59.4% of food weight). A noticeable part belongs to decapods (19.8%) and fish juveniles (16.6%). The smallest analyzed specimens consume small decapods and polychaetes. At the body length over 40 cm, L. tanakae pass over to predation. The value of the daily ration of Lycodes tanakae is, on average, 1.5% of the body weight.

On the systematic position of the genus Petroschmidtia Taranetz et Andriashev, 1934 (Perciformes: Zoarcidae)

Following a comparative analysis of the morphological characters of the representatives of the genera Petroschmidtia and Lycodes, some previously proposed diagnostic characters of Petroschmidtia are confirmed and ascertained and several additional characters are suggested. The conclusion on the taxonomic validity of the genus Petroschmidtia is confirmed. Petroschmidtia differs from Lycodes in the following features: teeth and tooth plates on the vomer and palatinum are lacking; bone fontanels of the supraorbital canal on the frontale are lacking; the vomer is shortened; the ethmoidalia lateralia are narrowed, bearing a pocketlike cavity inside the lateral lobes; the fan-like expanded outgrowth of the supraoccipitale is short, blunt; the dentale is shortened; the radialia are dorsoventrally flattened, the lowest of which is the largest. The genus Petroschmidtia is assumed to be morphologically more closely related to Lycodes than any other of the Lycodinae.

First occurrence of the bony flying fish Hirundichthys oxycephalus (Exocoetidae) in waters of Russia

551 Up to the present, in the Far East waters of Russia, the family of Exocoetidae comprises six rare epipe lagic subtropical tropical species: Exocoetus monocir rhus Richardson, 1846, Hirundichthys gilberti Parin et Belyanina, 2002, Cheilopogon heterurus doederleinii Steindachner, 1887, Ch. pinnnatibrarbatus japonicus (Franz, 1910), Cypselurus hiraii Abe, 1953, and Prog nichthys sealei Abe, 1955 (Parin, 1960a, 1960b, 1961, 1962, 1996; Savunykh, 1998; Fedorov and Parin, 1998; Parin and Shakhovskoy, 2000; Novikov et al., 2002; Parin, 2002; Sokolovskii et al., 2007, 2009; Kharin et al., 2007). The first flying fish Cheilopogon heterurus doederleinii in waters of Southern Primor’e was recorded as early as 1926 off Basargin Cape (Peter the Great Bay, the Sea of Japan) (Soldatov and Lind berg, 1930; Parin, 1960a, 1960b, 2002). At present, four species of these fish are recorded (H. gilbertii and Ch. pinnnatibrarbatus japonicus are known from single captures in the southern part of the Russian Pacific zone—Fedorov and Parin, 1998) occurring here from July to September, penetrating with warm currents from the southern part of the Sea of Japan.

Embryonic and early larval development of Cottus czerskii Berg, 1913 (Scorpaeniformes: Cottidae)

The embryonic and early larval development of the Cherskii’s sculpin Cottus czerskii Berg, 1913 was studied. The duration of the embryonic period was 21 days at a water temperature of 9–10°C. Pelagic larvae of approximately 8.0 mm total length leave the egg envelopes, with a large rounded yolk sac with one large oil globule, 10–12 trunk and 30–31 precaudal myomeres and several large melanophores on the yolk sac, 2 melanophores in the peritoneal region, and 30 melanophores in a postanal ventral row. At 11 days after hatching at a length of 9.0 mm, the yolk sac is completely resorbed and the number of myomeres remains the same; seven rays become visible in the caudal fin. The fully formed larva of C. czerskii has an elongated body, a small head, a rounded snout, and an oblong tail part. The melanophores are located in the peritoneal area above the gut, in the abdominal area, and in the postanal ventral row. Armament in the form of spines on the top of the head is absent, pointing to the affiliation of the species that we studied to the Cottus–Leptocottus phenetic group.

The first data on the biology and distribution of the Japanese fringed sculpin Porocottus japonicus Schmidt, 1935 (Scorpaeniformes: Cottidae) in the northwestern Sea of Japan

The Japanese fringed sculpin Porocottus japonicus Schmidt has been found in the Rynda (44°48′03″ N, 136°23′24″ E) and Vladimira (43°52′36″ N, 135°29′30″ E) (Sea of Japan, Primorskii krai) bays for the first time. This species was formerly known only from the northern Tatar Strait and Aniva Bay. In Primorskii krai, P. japonicus inhabits macrophyte beds in shallow sublittoral waters. It reaches a length of 112 mm during its lifespan of approximately 4 years. Spawning occurs in the winter. The species preys predominantly on polychaetes (82.3% of the food weight).

Spatial Distribution and Thermal Regime of Habitation of Two Representatives of the Genus Lycodes (Perciformes: Zoarcidae) in Russian Waters of the Sea of Japan

Main features of spatial distribution and thermal regime of habitation of Lycodes nakamurae and L. yamatoi in Russian waters of the Sea of Japan are discussed. Comparative analysis of specific features of distribution of eelpouts of the mesobenthal group (L. nakamurae, L. yamatoi, L. tanakae) in some areas of the Sea of Japan with different hydrological conditions is provided. No horizontal migrations directed along isobaths were revealed in these species. In Russian waters of the Sea of Japan, L. nakamurae inhabits depths 130–760 m, preferring the range of depths 200–700 m (it was found in catches of 95.7% of trawlings); L. yamatai inhabits depths 140–800 m, but most frequently is found in the range of depths 200–500 m (86.1% of trawlings). L. nakamurae occurs at a temperature of 0.4–1.2°C and L. yamatoi is found at 0.3–1.9°C. Seasonal migrational activity in the former species is more pronounced than in the latter. Spring-summer migration towards the shelf for feeding and reproduction and autumn-winter wintering migration towards the continental slope taking place with the cooling of the shelf are noticeable. Maximum range of vertical migrations is typical of medium-size fish and minimal is typical of juveniles of the studied species that inhabit the upper section of the bathyal (200–400 m). It is suggested that the lower limit of distribution of eelpouts of the mesobenthal group in the southern and northern sectors of the Sea of Japan coincide. The upper boundary of habitation of the species in different seasons of the year is totally determined by the thermal regime of water masses in different areas of the sea.

The Formation of the Lycodinae Fauna (Perciformes: Zoarcidae) of the Sea of Japan

The subfamily Lycodinae is represented in the Sea of Japan by two genera (Lycodes and Petroschmidtia) and seven species (Lycodes japonicus, L. nakamurae, L. raridens, L. tanakae, L. teraoi, L. yamatoi, and Petroschmidtia toyamensis), which are widely distributed on the shelf and upper continental slope. Based on the geographic and bathymetric distribution of eelpouts of the Sea of Japan and adjacent waters, two groups of closely related species with different types of distribution ranges were distinguished. The first group includes pairs of species that live primarily on the continental slope and are completely isolated in the Sea of Japan or in the Sea of Okhotsk. The second group is comprised of upper interzonal species of the Sea of Japan that are found on the continental slope and shelf, as well as in the southern Sea of Okhotsk from Terpeniya Bay to the southern Kuril Islands. Their related species in the Sea of Okhotsk are mostly found to the north of the Terpeniya Bay. The study of the eelpout distribution and the data on the geological history and paleoclimate of the Far East show that the Lycodinae fauna of the Sea of Japan was formed from North Pacific eelpout-like fishes during the isolation of the sea in the late Pliocene-early Pleistocene, which was concomitant with the general cooling of the Earth’s climate. During the Pleistocene interglacials, the eelpout migrations were unidirectional, from the Sea of Japan to the southern Sea of Okhotsk. The reconstruction of the formation of the Sea of Japan Lycodinae fauna suggests that the related taxa from the Sea of Japan and the Sea of Okhotsk are separate species, while the northern and southern forms of species from the Sea of Japan (Lycodes yamatoi and L. teraoi) are no more than subspecies.

Morphological Description, Intraspecific Variation, and Relationships of Cherskii’s sculpin Cottus czerskii (Cottidae)

Detailed morphological description of Cherskii’s sculpin Cottus czerskii (Cottidae) is conducted. Main directions of intraspecific variation of the phenotype are described. The ontogenetic variation of 24 of 31 morphometric characters is registered. The characters are subdivided into four categories based on the features of their variation and degree of ontogenetic allometry. Sexual dimorphism is observed based on the following characters: length of the rays of the pelvic fin, length of the anal fin base, depth of the anal fin, antedorsal distance, and head depth. A latitudinal increase of the fin rays in the anal and pectoral fins from the southern to the northern parts of the biogeographic range is registered. The relationships of the species with other representatives of the family Cottidae are discussed based on the comparative analysis of morphological and ecological features. A complex of plesiomorphic morphological and ecological characteristics, which are similar to those in more ancient catadromous, brackish-water, and marine forms, is described. Based on morphological characters, C. czerskii is substantially similar to C. hangiongensis.

Finding of Amur sculpin Mesocottus haitej and Cottus szanaga (Cottidae) in Tugur River basin (Khabarovsk krai, Russia)

The first official finding of the Amur sculpin Mesocottus haitej and Cottus szanaga is reported for the basin of Tugur River (Shantarsky zoogeographical region). Previously, these species were known for this region from the literature only.