


Vol 59, No 3 (2019)
- Year: 2019
- Articles: 24
- URL: https://journals.rcsi.science/0032-9452/issue/view/10257
Article
Description of a New Species of Pelagic Eelpouts Melanostigma japonicum sp. nova (Zoarcidae) from the Pacific Coast of South Japan with a Key for the Species of the Genus Melanostigma from the Pacific Ocean and the Adjacent Waters of the Indian and Southern Oceans
Abstract
A new species of Melanostigma japonicum sp. n. is described from the Tosa Bay (Southern Japan). The holotype of the species, previously identified as M. orientale, differs from the latter and other Melanostigma species by a unique structure of jaws with very large anteriorly protruding front teeth, an original combination of a number of meristic characters, coloration, and body proportions. M. flaccidum, previously placed in the synonymy of M. gelatinosum, is restored as the valid species. The issues of origin and historical dispersal of Melanostigma species are discussed. A key for identifying the species of this genus in the Pacific Ocean and in the adjacent waters of the Indian and Southern Oceans is provided.



Taxonomic Status of the Okhotsk Lumpsucker Eumicrotremus ochotonensis (Cyclopteridae, Cottoidei) with Redescription of E. derjugini
Abstract
The species status is justified for the Okhotsk lumpsucker Eumicrotremus ochotonensis based on the morphological characters. The differences from the closely related species E. derjugini inhabiting the Arctic Ocean are given. Two species were redescribed basing on type series, their diagnoses were clarified, and the lectotypes were designated. Intraspecific variability is discussed using new materials from the Barents, Kara, Laptev, and Okhotsk seas. The two species differ markedly in a complex of morphological features (shape of the submerged dorsal fin, proportions of the body, number and location of bony plaques) and characteristics of biology (spawning season). The modern disjunction of the ranges of E. ochotonensis and E. derjugini covers the Bering, East Siberian, and Chukchi seas. Sequence analysis of the cytochrome oxidase (COI) gene fragment of mtDNA revealed differences in the haplotypic diversity of the two species. Weak genetic divergence between species indicates a relatively recent isolation of E. derjugini and confirms its status of the evolutionary young species.



Morphological Variability of Big-Scaled Redfin Tribolodon hakonensis (Cyprinidae)
Abstract
Morphological variability of seven characteristics of two forms of the big-scaled redfin Tribolodon hakonensis from ten reservoirs of the Far East is studied. Three indicators are analyzed—fluctuating asymmetry, geographical variability, and variability of characteristic values. Differences in the level of fluctuating asymmetry of T. hakonensis from different samples are due to different conditions of embryonic and early postembryonic development. The northern form differs from the southern one by a large average value of the sum of dispersions in all characteristics; this indicates a reduced stability of development. The geographical variability of T. hakonensis is manifested in six characteristics. Forms reliably differ from each other by average values of features, except for the number of infraorbital bones. The average values of the coefficient of variation of characteristics vary considerably; the forms do not differ among themselves, and this indicator is noticeably higher only by the number of postorbital bones in the southern form. The largest number of significant differences in the dispersion of fluctuating asymmetry, average values of characteristics, and coefficients of variation is most often observed when comparing between samples of the northern form, while that for the southern one is always minimal or absent altogether; this may be a result of sampling of the northern form from a much larger part of the area and a higher level of nucleotide variability in the northern form compared with the southern one.



Identification of Hybrids between the Far Eastern Redfins Tribolodon hakonensis and T. brandtii Based on the Cephalic Lateral-Line System and Four Molecular Genetic Markers
Abstract
Three species of the genus Tribolodon (T. hakonensis, T. brandtii, and T. sachalinensis) and hybrids between T. hakonensis and T. brandtii have been analyzed using the cephalic lateral-line system and four molecular genetic markers: nuclear DNA (Rho and ITS-1–5.8S–ITS-2) and mitochondrial DNA (Co-1 and Cyt-b). It was shown that the presence of a connection between postopercular and preopercularmandibular canals of the cephalic lateral line on one side of the head (such connection on both sides of the head is a characteristic of T. brandtii) and the absence of such a connection on the other side (such connection on both sides of the head is a characteristic of T. hakonensis), along with p-distances for markers Rho, ITS-1–5.8S–ITS-2, Co-1, and Cyt-b, can reveal hybrid individuals between T. hakonensis and T. brandtii.



Large African Barbs with Hypertrophied Lips and their Relationship with Generalized Forms of Species of the Genus Barbus (Labeobarbus auctorum)
Abstract
Geographical variation in the large African barbs with hypertrophied lips (morphotype LIP) and in the individuals of the generalized form (GF) is studied in the water bodies of Ethiopia. The analysis of phenetic relationships for the samples of the Barbus intermedius complex and the species B. gananensis shows that, in the majority of cases, the samples of LIP are closer to the samples of GF from the same water body than to the samples of LIP from other localities. Thus, in the majority of localities (or in all localities), the morphotype LIP is most likely a derivative of the sympatric generalized form. The similarity of LIP individuals from different localities in lips structure and shapes of the dentary and premaxilla should be considered as a homoplasy.



Ontogenetic Otolith Development in an Endemic Tooth-Carp, Aphanius vladykovi (Teleostei: Aphaniidae)
Abstract
Otolith morphology in the tooth-carp/killifish genus Aphanius is an important source of taxonomic information. However, little is known about the range of ontogenetic variation in otolith morphology. In this study, the development of otolith morphology during the early life stages of the Zagros tooth-carp, Aphanius vladykovi is described and discussed. The study material comprises 15 larvae and early juveniles representing nine different developmental stages (0–120 days post hatching), all reared under the same laboratory conditions. The results reveal (i) clear ontogenetic differences in otolith morphology during larval and early juvenile growth phases, (ii) a developmental progression in otolith morphology, which is similar to that described for A. farsicus in a previous study, and (iii) a more rapid rate of otolith development during the larval phase in A. vladykovi than in A. farsicus. It can be hypothesized that the shared pattern of overall development seen in A. vladykovi and A. farsicus reflects their close phylogenetic relationship.



Number Dynamics of Mass Ichthyoplankton Species in the Waters of Morocco
Abstract
Data on the number dynamics of the mass fish species at early developmental stages in the northern and southern regions of Morocco during 2003–2016 have been analyzed. The values of number index and absolute number of eggs and larvae of the mass fish species have been calculated. As a rule, the values of absolute number of ichthyoplankton are 1.3–2.9 times higher than of the number index values. In general, the trends of interannual fluctuations of these values are similar. The study revealed that the patterns of fluctuations of the subtropical fish species at early developmental stages (European pilchard Sardina pilchardus, Atlantic horse mackerel Trachurus trachurus, and mackerel Scomber japonicus colias) are similar over the whole study area within the Morocco economic zone (32°–21° N). The fluctuations in the number of the tropical fish eggs and larvae (round sardinella Sardinella aurita and Cunene horse mackerel T. trecae) are not identical in the northern and southern parts of Morocco. No clear correlation between these fluctuations in the bordering regions is revealed.



Winter Fish Distribution in the Riverbed Depression in the Urtysh River
Abstract
Winter fish distribution is investigated by means of computerized hydroacoustic complexes in the largest riverbed depression in the Irtysh. Fish aggregations whose position, density, abundance, and size composition are much modified during winter are formed under ice in the riverbed depression. In the early winter, the density and abundance of fish aggregations are higher than those before spring. Distribution of fish over the depression changes from month to month, but the attribution of most fish to open water and to near-surface layers remains invariable. In the water area of the depression, the fish are combined into dynamic aggregations. Under ice, the majority of the fish are represented by small-sized cyprinids (Cyprinidae).



Age and Growth of the Black Scorpionfish Scorpaena porcus Linnaeus, 1758 (Scorpaeniformes: Scorpaenidae) under Anthropogenic Pressure in the Black Sea
Abstract
Age structure and growth dynamics are examined for the black scorpionfish Scorpaena porcus Linnaeus, 1758, from three sites characterized by different levels of pollution: Kazach’ya, Alexandrovskaya, and Streletskaya bays. No substantial differences were found in age structures, which largely correspond to the natural state of the population; differences between the mean age in the least polluted Kazach’ya Bay and the most polluted Streletskaya Bay are not significant (p = 0.35). According to the indicators L∞, W∞, k of females, φ of females, and φ' of females, the black scorpionfish from the least polluted Kazach’ya Bay is characterized by a higher growth rate. However, nonsignificance of differences in the values of these parameters in comparison with the more polluted Streletskaya and Aleksandrovskaya bays does not allow an unambiguous conclusion to be made about the fish growth delay in the latter two.



Sex Change in Protogynous Fish Red-Belted Anthias Pseudanthias rubrizonatus (Serranidae) in Kagoshima Bay, Japan
Abstract
The Serranidae are well known for protogynous sex change. The red-belted anthias Pseudanthias rubrizonatus inhabits Kagoshima Bay. We aimed to estimate the body size and age of P. rubrizonatus exhibiting sex change. We determined their sex based on the body color and the observation of their gonad. The sampled fish were 0–7 years old, although no individuals 1 or 6 years old were found. The fork length (FL) ranged from 10 to 114 mm. According to estimates from growth curves calculated from the body size of fish of each sex, the theoretical size of individuals exhibiting sex change was 96.9 mm FL and 14.1 g body weight. Gonadal transitions were observed in fish of 81–100 mm FL, 7–14 g body weight, and 2–3 years old, regardless of their apparent sex. These gonads included atretic oocytes in the testis. Most males had ovarian cavities in the testis. Histological observation showed that P. rubrizonatus is a protogynous fish species.



The Modern Status of Populations and Feeding Habits of the Longtail Dwarf Goby Knipowitschia longecaudata (Gobiidae) in the Don River Delta and the Eastern Part of Taganrog Bay
Abstract
The size and sex composition and feeding habits of the longtail dwarf goby Knipowitschia longecaudata have been studied in the Don River delta and in the eastern part of Taganrog Bay. The maximum size of specimens has increased compared to the 1950s, which is, probably, caused by a decreasing pressure of predatory fishes. The change in the spectrum of food objects caused by the transformation of the zooplankton species structure and occurrence of marine forms as a result of an increase in water salinity has been found. The specific abundance and biomass of the species have been estimated for the first time: the maximum abundance reaches 36400 ind./ha in the eastern part of Taganrog Bay and 6700 ind./ha in the Don River delta; the biomass is 5.0 and 1.7 kg/ha, respectively. The features of the spatial and temporal distribution of the abundance and biomass of K. longecaudata have been analyzed.



Tolerance of Juvenile Perch Perca fluviatilis and Amur Sleeper Perccottus glenii to Predation by Pike Esox Lucius
Abstract
The tolerance of juvenile Amur sleeper Perccottus glenii and perch Perca fluviatilis to the effect of piscivorous predator pike Esox lucius has been studied in experimental conditions. In the majority of trials, Amur sleepers were consumed by pike much more efficiently. This trend remained in the aquaria of various volumes, with and without covers. As opposed to perch, juvenile sleeper do not rely on the behavioral responses of group defense, and this leads to its higher vulnerability to predation in the experimental conditions. The data of the present study confirm the results of field research on the key effect of piscivorous predators on the possibility for colonization of Amur sleeper in certain waterbodies.



Palatability of Water Organisms for Nile Tilapia Oreochromis niloticus (Cichlidae)
Abstract
The palatability of six species of aquatic animals and five species of plants for the Nile tilapia Oreochromis niloticus was evaluated. Aqueous extracts of most organisms (ten of 11 species) have an attractive taste, which corresponds to euryphagia and nutritional plasticity of the Nile tilapia. Despite phytophagia, the palatability of an animal extract is higher than that of plants. The low stimulating effect of the extract of the duckweed Lemna minor suggests the presence of natural taste deterrents in it. The extract of the Canadian waterweed Elodea canadensis, depending on the origin of the plant, either completely blocks consumption or has inert taste properties. Different parts of the water hyacinth Eichhornia crassipes (leaves, roots) have a similar palatability. Repeated grasps manifested during orosensory testing of food are not typical for feeding behavior of the Nile tilapia. The results of the study indicate the ability of fish to subtly differentiate food organisms according to their taste qualities and emphasize the important role of taste reception in the choice of food objects by fish.



The Effect of pH on the Supply of Digestive Hydrolases in Fish with Different Feeding Habits
Abstract
The effect of pH on the activity of peptidases and glycosidases functioning in the intestine and the supply of these enzymes in five fish species from the Rybinsk Reservoir with different feeding habits (roach Rutilus rutilus, bream Abramis brama, perch Perca fluviatilis, zander Zanderlucioperca, and pike Esox lucius) has been studied. In all fish species, the maximum activity of intestinal caseinolytic peptidases and their provision in the specimens was recorded at pH 9, and that of glycosidases was recorded at pH from 7 to 8. The pH values corresponding to the maximum values of the glycosidase activity were similar to those recommended for assessment of the enzyme activity in the digestive tract of vertebrates; values of peptidases were considerably higher. It is suggested that differences in the effect of pH on the provision of peptidases and glycosidases depend on features of the feeding spectrum of the fish species studied.



Lipid Profile of the Young Atlantic Salmon Salmo salar L. in the Letnyaya Zolotitsa River (Arkhangelsk Oblast, White Sea Basin)
Abstract
The lipid status of juvenile Atlantic salmon Salmo salar L. at the age of 0+, 1+, 2+, and 3+ was studied in the Letnyaya Zolotitsa River (the White Sea basin) in August 2015. The young-of-the-year juveniles have a relatively low lipid status on total lipids, especially reserve triacylglycerols, compared with elder juveniles (1+ to 3+). The proportion of long-chain polyunsaturated fatty acids (22:6n-3, 20:5n-3 and 20:4n-6) decreases with age (especially in 3+ individuals), but the proportion of reserve triacylglycerols and monounsaturated fatty acids (16:1n-7, 18:1n-9, and 18:1n-7) increases. The age-related changes in the ratio of reserve and structural lipids were analyzed. A low content of fatty acids typical for marine fishes (22:6n-3, 20:5n-3, and 20:4n-6) found in the 3+ juveniles, a reduced degree of their conversion from dietary fatty acids (18:2n-6 and 18:3n-3), and the lack of energy-rich triacylglycerols and monounsaturated fatty acids indicates that the young specimens are not ready for the transition to the marine environment. These indicators of the lipid status of juvenile salmon can be used as additional biochemical indicators of metabolic processes associated with the fish migration to another habitat.



Short Communications
A New Species of Lizardfishes of Genus Trachinocephalus from the Western Indian Ocean (Synodidae)
Abstract
Trachinocephalus atrisignis sp. n. is described from three specimens caught in the western Indian Ocean near Socotra Island. It differs from other representatives of the genus by a saturated black spot on the dorsal fin tip, the shape of the snout and lower jaw, and somewhat lower number of vertebrae and lateral line scales.



Brachirus sayaensis, a New Soleid Species (Soleidae: Pleuronectiformes) from Saya de Malha Bank
Abstract
Two soleid specimens from Saya de Malha Bank are described as Brachirus sayaensis sp. nov. It is distinguished from other soleid species by the combination of the following characters: caudal fin joined to dorsal and anal fins, pectoral fins very short, but present, total number of vertebrae 45–46; first ray of dorsal fin not enlarged and free; scales ctenoid on both sides of body; body slightly elongate, no bony process on snout; eyes separated by an interorbital space; opercular membrane free from the body; no labial fringes; pelvic fin of eyed side free, not joined to anal fin; anterior nostril of ocular side does not reach anterior margin of lower eye, dorsal fin rays 77, anal fin rays 61–62, lateral line scales 97–105, color of ocular side in alcohol light brownish, no stripes and spots.



A New Species of Serranids of Genus Pseudogramma from the Indian Ocean (Serranidae)
Abstract
The new species Pseudogramma cernunnos sp. n., which is close to West Atlantic P. gregoryi and South Pacific P. australis (Easter Island) and P. xantha (Polynesia) but differing by pattern on the head and several meristic and plastic characters, is described from the Bay of Bengal near the Andaman Islands. The new finding fills the gap between distribution ranges of the previously known species of this complex and indicates possible ways for distribution of these species.












Effect of Thiourea and Starvation on the Physiological and Biochemical State and the Reproductive System of Climbing Perch Anabas testudineus
Abstract
The effects of thiourea (keeping of fish for 32 days in 0.05% solution of thiourea) and of starvation (during 12 days) on the physiological and biochemical state and on the reproductive system of mature males of climbing perch Anabas testudineus are investigated. Combination of these two factors results in a decrease in the level of sex steroid hormones (testosterone and estradiol-17β) in blood, in changes in synthesis of thyroxine, in its conversion to triiodothyronine, and in acceleration of spermatogenesis.



Functional Properties of Hemoglobin in Bream Abramis brama and in Crucian Carp Carassius carassius at Hypoxia
Abstract



Errata
Erratum to: Transoceanic Migration of Pacific Lamprey, Entosphenus tridentatus


