Lipids in the daubed shanny (Teleostei: Leptoclinus maculatus) in Svalbard waters

The daubed shanny, Leptoclinus maculatus, is a common fish species in Arctic and North Atlantic waters and has an important role in high-latitude ecosystems as a link between lower trophic levels and many fish, marine mammal and seabird species. Its biology and ecology have, however, remained largely unstudied. The primary aim of this study was to increase the knowledge about the daubed shanny by analysing total lipids, lipid-classes and the fatty acid composition of liver, muscle and female gonads in adults from the high Arctic archipelago of Svalbard. In female gonads, the triacylglycerols and wax esters in addition to cholesterol esters were dominant among the stored lipids. Triacylglycerols dominated in the liver, whereas structural lipids, such as phospholipids and cholesterols, were the most important lipids in muscles. Phosphatidylcholine and phosphatidylethanolamine were major phospholipids in all organs studied. The fatty acid spectrum of the investigated organs was characterized by a high amount of monounsaturated fatty acids, particularly in the liver. Polyunsaturated fatty acids, particularly 22:6(n-3) and 20:4(n-6), were prevalent in muscle tissues. The lipid and fatty acid spectra in the organs during this period of life are tightly connected with the activation of the liver metabolism and the storage of lipids in the developed female gonads. Lipid accumulation and distribution in gonads are transferred to optimal development of embryos and larvae in Arctic waters.     

Comparative Study of Lipid Content in Leptoclinus maculatus Postlarvae from Kongsfjord and Rjipfjord,Svalbard Archipelago

Doklady Biochemistry and Biophysics - A comparative study of lipid profile of the daubed shanny Leptoclinus maculatus postlarvae from fjords of different domains (arctic-boreal Kongsfjord and...     

Uptake of foreign ferritin in platy Xiphophorus maculatus (Poeciliidae: Teleostei)

The ability and capacity of various tissues in platy Xiphophorus maculatus L. to take up horse-spleen ferritin injected into the blood stream are described. Ferritin was injected intraperioneally, and the cellular uptake was demonstrated as Prussian blue precipitations in tissues treated with acid ferrocyanide solutions. Ferritin was detected within the heart endocardial cells and macrophages in the trunk kidney and spleen, 1/4 h after the injection, i.e. foreign ferritin was taken up very rapidly by these cells. When the time elapsed between the ferritin injection and sacrifice exceeded 6 h, these cells, and also macrophages in the gill and intestine, were almost completely filled with ferritin. At these stages, however, the amounts of Prussian blue precipitations per volume unit of the tissue were much larger in the heart than in the other organs studied in the present work, i.e. the endocardial tissue seems to play an important role in the clearance of the blood circulation in this species. We suggest that this tissue in platy is specialized to endocytose waste and foreign macromolecules, including pathogenic particles, from the blood stream. The eosinophilic and neutrophilic granulocytes do not appear to take up foreign ferritin, i.e. these cells may play no endocytotic role in the clearance of foreign macromolecules in platy.     

Tilapia (Teleostei: Cichlidae) status in Nicaraguan natural waters

We surveyed the watersheds covering more than 80% of the surface area of Nicaragua, and review the history of deliberate introductions and unintentional invasion of tilapias, Oreochromis spp., into the freshwater of Nicaragua. The species have become widely established, with a range of negative consequences for the rich natural fish fauna of this Central American country. Tilapias compete directly with native cichlids in a number of ways, and have also supplanted native species as food fish in local markets. We suggest that introduced tilapias may have been responsible for the outbreak of blindness in native cichlids. We make recommendations on the management of these exotic species and on further introductions. An erratum to this article can be found at     

Hydroid epifaunal communities in Arctic coastal waters (Svalbard): effects of substrate characteristics

The knowledge of cryptic epifaunal groups in the Arctic is far from complete mostly due to logistic difficulties. Only recently, advances in sample collection using SCUBA diving techniques have enabled to explore delicate hydroid fauna from shallow waters. This study is the first attempt to examine the relationship between substrate property (such as size of rock, morphological characteristics of algal or bryozoan host) and hydroid community composition and diversity in the Arctic. Samples of substrates for hydroid attachment including rocks, algae, bryozoans and other hydrozoans were collected around the Svalbard. Examination revealed no substrate-specific species. The substrate property did not have a strong influence on hydroid community. Both species composition and richness were not related to colonized rock surface area and to morphological characteristic of algal host. Therefore, results indicate the opportunistic nature of hydroid fauna in terms of substrate preference. However, the presence or absence of hydroids depended on the surface area of rocky substrate. Hydroids were more often present on rocks of larger surface area. Erect hydroids and bryozoans were important attachment surface for stolonal hydroids.     

Identification of grey mullet (Teleostei: Mugilidae) juveniles from British waters

Examination of juveniles (25–50 mm t.l .) of the three species of grey mullet present in British and other nothern European waters has indicated that the melanophore pattern on the ventral surface of the head is a reliable and useful character for identification.     

The complete mitochondrial genome of the spotted steed, Hemibarbus maculatus (Teleostei, Cypriniformes)

The complete mitogenome sequence of the spotted steed (Hemibarbus maculatus) was determined using long PCR reactions. The genome is 16,611 bp long and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region. The gene order and composition of H. maculatus was similar to that of most other vertebrates. The base composition of H-strand in descending order is A (29.16%), C (27.41%), T (25.93%), and G (17.50%), with an AT content of 55.09%. The Kimura two-parameter distances between mitogenome sequences of H. maculatus and Hemibarbus labeo, Hemibarbus barbus, Hemibarbus longirostris, Hemibarbus mylodon were 2.09%, 2.35%, 12.77%, and 13.92%, respectively. The phylogenetic relationships among the five Hemibarbus species based on the whole mitogenome sequence data were (((H. barbus, H. labeo), H. maculatus), (H. longirostris, H. mylodon)).     

Histological studies on the lymphoid organs in prenatal larvae of platy,Xiphophorus maculatus L (Poeciliidae: Teleostei)

The thymus was very large and tightly packed by lymphocytes in prenatal larvae of platy, Xiphophorus maculatus L., whereas the lymphoid tissues in the spleen and trunk kidney were poorly developed at these stages. We therefore suggest that the specific cellular defence is developed much earlier than the corresponding humoral defence mechanisms in this species.     

Multivariate analyses in the taxonomy of two species of Tylodelphys Diesing, 1850 (Trematoda: Diplostomidae) from Galaxias maculatus (Teleostei: Galaxiidae)

Three Tylodelphys species are known to co-exist in the brain of Galaxias maculatus: T argentinus, T. barilochensis and T. crubensis. In order to determine the species present in the G. maculatus from Lake Gutiérrez, specimens were captured using baited traps every month from April to December, 1995. A total of 1,526 metacercariae were separated for identification, and multivariate techniques were applied on meristic variables measured on stained mounted metacercariae. Two species were identified through these techniques: T. barilochensis and T. crubensis.     

Megabenthic commmunities in the waters around Svalbard

 Composition and distribution of megabenthic communities around Svalbard were investigated in June/July 1991 with 20 Agassiz trawl and 5 bottom trawl hauls in depths between 100 and 2100 m. About 370 species, ranging from sponges to fish, were identified in the catches. Species numbers per station ranged from 21 to 86. Brittle stars, such as Ophiacantha bidentata, Ophiura sarsi and Ophiocten sericeum, were most important in terms of constancy and relative abundance in the catches. Other prominent faunal elements were eunephthyid alcyonarians, bivalves, shrimps, sea stars and fish (Gadidae, Zoarcidae, Cottidae). Multivariate analyses of the species and environmental data sets showed that the spatial distribution of the megabenthos was characterized by a pronounced depth zonation: abyssal, bathyal, off-shore shelf and fjordic communities were discriminated. However, a gradient in sediment properties, especially the organic carbon content, seemed to superimpose on the bathymetric pattern. Both main factors are interpreted as proxies of the average food availability, which is, hence, suggested to have the strongest influence in structuring megabenthic communities off Svalbard. Received: 28 April 1995/Accepted: 18 November 1995     

Ultrastructural data on the spore of Myxobolus maculatus n. sp. (phylum Myxozoa), parasite from the Amazonian fish Metynnis maculatus (Teleostei)

Light and electron microscopy studies of a myxosporean, parasitic in the intertubular interstitial tissue of the kidney of the freshwater teleost fish Metynnis maculatus Kner, 1860 (Characidae) from the lower Amazon River (Brazil), are described. We observed polysporic histozoic plasmodia delimited by a double membrane and with several pinocytic channels and containing several life cycle stages, including mature spores. The spore body was of pyriform shape and was 21.0 microm long, 8.9 microm wide and 7.5 microm thick. Elongated-pyriform polar capsules were of equal size (12.7 x 3.2 microm) and contained a polar filament with 14 or 15 coils. The spore features fit those of the genus Myxobolus. Densification of the capsular primordium matrix, which increased in density from the inner core outwards, differentiating at the periphery into small microfilaments measuring 45 nm each, and tubuli arranged in aggregates and dispersed within the capsular matrix of the mature spores, are described. Based on the morphological differences and specificity of the host, we propose the creation of a new species named Myxobolus maculatus n. sp.     

Diet of Lipophrys pholis (L.) (Teleostei,Blenniidae) in Cantabrian coastal waters (Spain)

Between February and December 1988, a total of 261 specimens of Lipophrys pholis were caught in eleven intertidal pools on the western coast of Asturias. This blenniid species mainly feeds on different groups of invertebrates, although algal remains also appear. Mollusca is the most highly represented taxon with the largest number of prey being Gastropoda, followed by Bivalvia and, to a lesser degree, Polyplacophora. Crustacea is well represented by Cirripedia. Isopoda also stands out and Amphipoda, Tanaidacea and Decapoda appear sporadically. Temporal diet analysis throughout the year shows no great differences. Likewise, a great similarity was observed among the feeding of L. pholis specimens collected in pools at a different tidal level, of variable size and with different algal cover. Changes in diet are appreciable as size increases, especially from a length of 6 cm on.     

Melano-macrophage centres in the liver of platyfish, Xiphophorus maculatus, Poeciliidae: Teleostei

This paper describes the localization and structure of melano-macrophage centres (MMCs) in the liver of platyfish (Xiphophorus maculatus), compares these centres with corresponding structures in the spleen and kidney of various teleosts and gives suggestions about their functions. The MMCs were closely apposed to the endothelial layer of liver venules covered with pancreas tissue, i.e. portal venules, and contained numerous cells displaying large amounts of Prussian blue precipitations in tissue treated with acid ferrocyanide. Thus, these centres were rich in ferric compounds, probably haemosiderin, and are suggested to be involved in the normal storage, relocation and recycling of iron compounds from effete or damaged red blood cells of the portal venule system in this species.     

<Emphasis Type="Italic">Leptoclinus maculatus diaphanocarus</Emphasis> (Schmidt, 1904) (Zoarcoidei: Stichaeidae) of the northen part of the Sea of Japan

Juveniles of Leptoclinus maculatus diaphanocarus were observed in great numbers in netting of bottom trawl in the period from April 28 to May 7 2007 in the Tatar Strait. Metamorphosis of juveniles reached its end at the body length from 8.5 to 11.0 cm. It was accompanied by change of coloration. After transition to the bottom mode of life, the frequency of occurrence of specimens of this species in catches drastically decreased. Principal counts are estimated, with consideration of additional material from far eastern seas of Russia. Two groups of specimens which would correspond to the Pacific and the Atlantic subspecies sensu Andriashev are not found. It is suggested that, for determination of the actual taxonomic status of intraspecies groups of the species L. maculatus, additional comparative material on morphology and genetics is needed from different regions.     

Biology of the radiated shanny Ulvaria subbifurcata Storer in Newfoundland (Pisces: Stichaeidae)

Ulvaria subbifurcata is found on the north-east Atlantic coast of North America. Fish less than 55 mm preyed predominantly on copepods, while larger ones ate mainly nereids; polynoids and amphipods were eaten by all sizes. These four food items comprised the main food of the radiated shanny. Spawning occurred in May with the fish first spawning at age three to five. No conspicuous secondary sexual characters were observed. Females spawned once per year, producing a demersal egg mass. Males spawned up to four times and tended the egg mass (or masses). Incubation lasted 35–40 days, and the pelagic larvae settles on the bottom by August. Adult males tended to be larger than females of the same age but little difference was found sexually in the length–weight relationships. Ulvaria subbifurcata larger than 60 mm are nocturnal. This may reduce predation by, and competition with, other inshore benthic fishes.     

Summer bacterio- and zooplankton in coastal waters of Svalbard

The distribution of bacterio- and zooplankton was studied in West Spitsbergen (Svalbard) coastal waters in August 2009. The bacterial abundance and biomass varied from 110 to 3360 × 10³ cells/ml and from 0.66 to 44.93 mg C/m³, respectively. These values were the highest in the surface water layers and decreased with depth. The greatest abundance of bacteria (5099 individuals/m3) was found in the freshened and warm water layer in Isfjorden. The highest biomass of zooplankton (182.41 mg C/m³) was registered in the zone of interaction of coastal and transformed Atlantic waters in the archipelago inner shelf. The spatial variations of abundance and biomass of the planktonic communities were related to the thermohaline characteristics of the water masses and, probably, to microalgal blooms.     

New metacercariae of the genus Tylodelphys (Trematoda, Diplostomatidae) in lacustrine populations of Galaxias maculatus (Teleostei, Galaxiidae)]

Metacercariae of three new species of Tylodelphys (Trematoda, Diplostomatidae) were found in the brain of Galaxias maculatus (Teleostei, Galaxiidae), at the Meliquina Lake, Neuquen Province, Argentina. These metacercariae are morphologically described as Tylodelphys argentinus n. sp., Tylodelphys barilochensis n. sp. and Tylodelphys crubensis n. sp. This is the first time that a stage of genus Tylodelphys is mentioned parasitizing Galaxias maculatus. Metacercariae of T. barilochen sis n. sp. were also found in G. maculatus brain at the Perito Moreno Lake, Rio Negro Province, Argentina.     

Growth and mortality of larval Myctophum affine (Myctophidae,Teleostei)

The growth and mortality rates of Myctophum affine larvae were analysed based on samples collected during the austral summer and winter of 2002 from south‐eastern Brazilian waters. The larvae ranged in size from 2·75 to 14·00 mm standard length (L_S). Daily increment counts from 82 sagittal otoliths showed that the age of M. affine ranged from 2 to 28 days. Three models were applied to estimate the growth rate: linear regression, exponential model and Laird–Gompertz model. The exponential model best fitted the data, and L₀ values from exponential and Laird–Gompertz models were close to the smallest larva reported in the literature (c. 2·5 mm L_S). The average growth rate (0·33 mm day^?1) was intermediate among lanternfishes. The mortality rate (12%) during the larval period was below average compared with other marine fish species but similar to some epipelagic fishes that occur in the area.