Osmotic,sodium, carbon dioxide and acid-base state of the Port Jackson shark,<Emphasis Type="Italic"> Heterodontus portusjacksoni</Emphasis>, in response to lowered salinity

In marine elasmobranch fish the consequences for CO₂ and acid–base state of moving into low salinity water are not well described. Sub-adult Port Jackson sharks, Heterodontus portusjacksoni, occasionally enter brackish water and survive in 50% seawater (SW). The unidirectional Na efflux and content, plasma volume, glomerular filtration rate (GFR), body mass, as well as CO₂ and acid-base state in H. portusjacksoni were investigated following transfer from 100% SW to 75% SW and then to 50% SW. A rapid water influx resulted in a doubling of the plasma volume within 24 h in sharks in 75% SW and an 11% increase in body weight. Osmotic water influx was only partially offset by a doubling of the GFR. There was a ~40% decrease in plasma [Na] through a transiently elevated Na clearance and haemodilution. The result was a decrease in the inward gradient for Na⁺ together with reductions of nearly 50% in CO₂ and buffer capacity. The sharks remained hypo-natric to 50% SW by partially conforming to the decrease in external osmotic pressure and avoided the need for active Na⁺ uptake. The gradient for Na⁺ efflux would by extrapolation approach zero at ~27% SW which may of itself prove a lethal internal dilution. In sharks transferred to 75% SW, a small transient hypercapnia and a later temporary metabolic alkalosis were all largely explained through anaemia promoting loss of CO₂ and buffer capacity. In sharks transferred to 50% SW the metabolic alkalosis persisted until the end of the 1-week trial. Within the erythrocytes, increased pH was consequent on the large decrease in haemoglobin content exhibited by the sharks, which caused a large reduction in intracellular buffer. In water as dilute as 50% SW there was no evidence of specific effects on the mechanisms of management of CO₂ or H⁺ excretion but rather significant and indirect effects of the severe haemodilution.Abbreviations a–v arterial–venous - CA carbonic anhydrase - C _a CO ₂ content of CO₂ in arterial blood - CCO ₂ CO₂ content - ⁵¹ Cr-EDTA ⁵¹chromium-ethylenediaminetetraactic acid - C _v CO ₂ content of CO₂ in venous blood - FW freshwater - GFR glomerular filtration rate - Hct haematocrit - J _out Na flux rate - MCHC mean cell haemoglobin concentration - OP osmotic pressure - P _a CO ₂ partial pressure of CO₂in arterial blood - PCO ₂ partial pressure of CO₂ - pH _a arterial blood pH - pH _er intra-erythrocyte fluid - pH _pl whole blood pH - pH _v venous blood pH - P _v CO ₂ partial pressure of CO₂in venous blood - SID strong ion difference - SW seawater - TMAO trimethylamine-N-oxide - UFR urinary flow rate Communicated by G. Heldmaier     

A new species of Ainudrilus (Tubificidae) from South Georgia,and other subantarctic freshwater oligochaetes

The freshwater oligochaetes of the subantarctic islands are reviewed and new records are given. Ainudrilus dartnalli sp.n. (subfamily Rhyacodrilinae) is described from freshwater sites on South Georgia (South Atlantic Ocean). It differs from the closely related, southwest Australian, A. nharna Pinder & Brinkhurst, by its longer clitellum, the longer upper teeth of its ventral somatic chaetae, its straighter and fewer penial chaetae, and by the proportions of its spermathecae. Range extensions are given for two widespread naidids, Nais variabilis Piguet and N. communis Piguet, from the Falkland Islands (S. Atlantic). Moreover, new material of N. elinguis Müller is recorded from Macquarie Island (Southern Ocean, SW of New Zealand).     

Molecular identification of three Trichinella isolates from Heilongjiang Province, People's Republic of China

DNAs of Trichinella dog isolate (HC), Trichinella swine isolate (HH) and Trichinella cat isolate (SW), obtained from Heilongjiang Province, were amplified by the fragments of 18S rDNA and ITS2. Two reference strains, Trichinella spiralis (ISS3) and Trichinella nativa (ISS10) were used for sequence comparison. Sequence and dendrogram analysis indicated that HC belonged to T.nativa and HH together with SW belonged to T.spiralis. This method permits rapid species identification of Trichinella isolates, although further evaluation is required before precisely identification.     

EST and Mitochondrial DNA Sequences Support a Distinct Pacific Form of Salmon Louse, <Emphasis Type="Italic">Lepeophtheirus salmonis</Emphasis>

Nuclear deoxyribonucleic acid sequences from approximately 15,000 salmon louse expressed sequence tags (ESTs), the complete mitochondrial genome (16,148bp) of salmon louse, and 16S ribosomal ribonucleic acid (rRNA) and cytochrome oxidase subunit I (COI) genes from 68 salmon lice collected from Japan, Alaska, and western Canada support a Pacific lineage of Lepeophtheirus salmonis that is distinct from that occurring in the Atlantic Ocean. On average, nuclear genes are 3.2% different, the complete mitochondrial genome is 7.1% different, and 16S rRNA and COI genes are 4.2% and 6.1% different, respectively. Reduced genetic diversity within the Pacific form of L. salmonis is consistent with an introduction into the Pacific from the Atlantic Ocean. The level of divergence is consistent with the hypothesis that the Pacific form of L. salmonis coevolved with Pacific salmon (Onchorhynchus spp.) and the Atlantic form coevolved with Atlantic salmonids (Salmo spp.) independently for the last 2.5–11 million years. The level of genetic divergence coincides with the opportunity for migration of fish between the Atlantic and Pacific Ocean basins via the Arctic Ocean with the opening of the Bering Strait, approximately 5 million years ago. The genetic differences may help explain apparent differences in pathogenicity and environmental sensitivity documented for the Atlantic and Pacific forms of L. salmonis. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Evidence for long‐term change in length,mass and migration phenology of anadromous spawners in French Atlantic salmon Salmo salar

This study provides new data on Atlantic salmon Salmo salar life‐history traits across France. Using a long‐term recreational angling database (1987–2013) covering 34 rivers in three regions (genetic units), a decline in individual length, mass and a delayed adult return to French rivers was reported. Temporal similarities in trait variations between regions may be attributed to common change in environmental conditions at sea. The relative rate of change in phenotypic traits was more pronounced in early maturing fish [1 sea‐winter (1SW) fish] than in late maturing fish (2SW fish). Such contrasted response within populations highlights the need to account for the diversity in life histories when exploring mechanisms of phenotypic change in S. salar. Such detailed life‐history data on returning S. salar have not previously been reported from France. This study on French populations also contributes to reducing the gap in knowledge by providing further empirical evidence of a global pattern in S. salar across its distribution range. Results are consistent with the hypothesis that the observed changes in life‐history traits are primarily associated with environmental changes in the North Atlantic Ocean. They also emphasize the presence of less important, but still significant contrasts between region and life history.     

Chromosome painting supports lack of homology among sex chromosomes in Oncorhynchus, Salmo, and Salvelinus (Salmonidae)

The sex chromosome pair has been identified previously as the largest submetacentric pair in the genome in several species of the genus Salvelinus (eastern trouts and chars) including S. namaycush (lake trout) and as a large subtelocentric/acrocentric pair in several species of the genus Oncorhynchus (Pacific trouts and salmon). Sex chromosomes have not been identified in Salmo (Atlantic salmon and brown trout). Two paint probes, one specific for the short arm (Yp) and the other for the long arm (Yq) of the sex chromosome pair in Salvelinus namaycush were hybridized to chromosomes of Oncorhynchus mykiss (rainbow trout) and O. tshawytscha (chinook salmon) and Salmo salar (Atlantic salmon) and S. trutta (brown trout). The two probes hybridized to two different autosomal pairs in each of the Oncorhynchus species, supporting lack of homology between the sex chromosomes in the two genera. The Yp probe hybridized to interstitial regions on two different chromosome pairs in S. salar and one pair in S. trutta. The Yq probe hybridized to a different pair in both species.     

Incongruent phylogeographies in spite of similar morphology, ecology, and distribution:Phippsia algida andP. concinna (Poaceae) in the North Atlantic region

Phylogeographic and taxonomic relationships among 54 North Atlantic populations of the snowbed grass genusPhippsia were investigated based on isozymes and genetically based morphological variation. The results support recognition of two distinct species,P. algida andP. concinna, the latter with at least two subspecies. Both of these self-fertilizing arctic pioneer species were genetic allotetraploids almost without intrapopulational variation. The two species showed strikingly different phylogeographies in the North Atlantic region in spite of their similarity in morphology, habitat ecology, mating system, and dispersal ecology, and in spite of their present cooccurrence in many geographic areas, sometimes even in the same snowbeds. The same electrophoretic multilocus phenotype was observed in all populations ofP. algida, and although this species showed considerable morphological variation, the variation was unstructured geographically. Thus,P. algida showed a pattern similar to other arctic species investigated in the North Atlantic region; it has probably dispersed postglacially across the sea barriers among Greenland, Svalbard, Iceland, and Scandinavia. In contrast,P. concinna was virtually fixed for different multilocus phenotypes in the three main geographic areas analyzed (S Norway, Svalbard, Greenland), corresponding to fairly distinct divergence in morphology. This pattern suggests absence of postglacial among-area dispersal ofP. concinna in spite of all of its similarities with its congener; it may have immigrated to the North Atlantic from different source areas and/or survived the last glaciationin situ.     

Pothos crassipedunculatus,a new species ofPothos sect.Allopothos (Araceae) from India

Pothos crassipedunculatus Sivadasan & Mohanan (Araceae), a new species closely related to the SW. Indian endemic and little known speciesP. thomsonianus Schott is described. It is characterized by the the non-ligulate, shortly vaginate petiole, thickly peduncled inflorescence, broadly ovate spathe and a sessile spadix. It is included in ser.Brevivaginati Engler of sect.Allopothos Schott.     

Marine sponges (Porifera) from the Bahía San Antonio (North Patagonian Gulfs,Argentina), with additions to the phylogeography of the widely distributed Cliona aff. celata and Hymeniacidon perlevis,and the description of two new species

Six sponge species from Bahía San Antonio (north Argentinean Patagonia) are (re)described, including two new species, namely Halichondria (Halichondria) elenae sp. nov. and Clathria (Microciona) saoensis sp. nov., and three new records for the Argentinean coast. Halichondria (H.) elenae sp. nov. is the only yellowish-greenish SW Atlantic Halichondria with oxeas up to 450?µm. The new species’ 18S rRNA blasted with Halichondria bowerbanki from Ireland, but it is argued that co-specificity is unlikely, in view of their rather distinct morphologies. Clathria (M.) saoensis sp. nov. is the only C. (Microciona) in the SW Atlantic, SE Pacific, and (sub)Antarctic regions with smooth (or nearly so) principal megascleres, mostly below 500?µm long, as well as moderately curved toxas, and isochelae of regular non-cleistochelate shape. Cliona aff. celata and Hymeniacidon perlevis had their identifications confirmed by the sequencing of their 28S and 18S rRNA genes, respectively, and mitochondrial CO1. Both of them clustered with previously sequenced specimens from the Temperate North Atlantic, apart from additional samples from SE Brazil, in the case of C. aff. celata, and China and South Korea, in the case of H. perlevis.     

Genista valsecchiae (Leguminosae), a new species from Sardinia

Genista valsecchiae from SW Sardinia is described and illustrated as a species new to science. It is very similar toG. ephedroides and can be distinguished by morphological differences of habit and inflorescence. It typically occurs in the garigue or maquis and is widespread in SW Sardinia.     

Bolboforma — an overview

A summary of the present knowledge ofBolboforma is presented in this paper. The genusBolboforma contains a diverse group of marine, mostly single-chambered enigmatic microfossils (phytoplankton, possibly Chrysophyta) which produced calcitic monocrystalline spheroidal tests with or without inner cysts and with various types of ornamentation. The genusBolboforma occurs in the time interval between late Early Eocene to Late Pliocene, at middle and higher latitudes, and thus, has not been recorded in Quaternary to Recent Sediments. The genus is represented globally, but the first and the last occurrence of the genus appear to be spatially diachronous in both hemispheres.Bolboforma started in the southern hemisphere at the Campbell Plateau (SW Pazific) during the Early Eocene approximately 53 Ma ago, and the genus lived there until latest Miocene times (5.3 Ma at the Kerguelen Plateau, Southern Indian Ocean). The first occurrence ofBolboforma in the northern hemisphere is observed in Upper Eocene Sediments (ca. 36.5 Ma) in the Labrador Sea (North Atlantic), and its youngest occurrence is observed in the Hatton-Rockall Basin (North Atlantic) in the Late Pliocene at 2.84 Ma. Well established and common species permit the definition of nineteenBolboforma zones/subzones. Not all of these are observed in both hemispheres. In the southern hemisphere all four Paleogene zones, but only eight Neogene zones are present, in the northern hemisphere only one Paleogene zone, but fourteen Neogene zones have been determined. Bolboforma distribution, which appears to be broadly bipolar in temperate to cool regions at middle to higher latitudes, aso seems to be linked to the evolution of surface watermasses and their boundaries.      

Asian medaka fishes offer new models for studying mechanisms of seawater adaptation

Japanese medaka (Oryzias latipes) is a freshwater (FW) teleost that is popular throughout the world for laboratory use. In this paper, we discuss the utility of Japanese medaka and related species for studying mechanisms of seawater (SW) adaptation. In addition to general advantages as an experimental animal such as their daily spawning activity, transparency of embryos, short generation time and established transgenic techniques, Japanese medaka have some adaptability to SW unlike the strictly stenohaline zebrafish (Danio rerio). Since other species in the genus Oryzias exhibit different degrees of adaptability to SW, comparative studies between Japanese medaka, where molecular-biological and genetic information is abundant, and other Oryzias species are expected to present varying approaches to solving the problems of SW adaptation. We introduce some examples of interspecies comparison for SW adaptabilities both in adult fish and in embryos. Oryzias species are good models for evolutionary, ecological and zoogeographical studies and a relationship between SW adaptability and geographic distribution has been suggested. Medaka fishes may thus deliver new insights into our understanding of how fish have expanded their distribution to a wide variety of osmotic environments.     

Influence of genotype and geography on shell shape and morphometric trait variation among North Atlantic blue mussel (Mytilus spp.) populations

The influence of geography and genotype on shell shape (outline) and trait (morphometric) variation among North Atlantic blue mussels and their hybrids has been examined. Shape differences among reference taxa (Mytilus trossulus, Mytilus edulis and Mytilus galloprovincialis) were consistent with an association between taxon‐specific genes and shape genes. Newfoundland M. edulis × M. trossulus populations and northern Quebec M. trossulus populations exhibited an uncoupling of taxon‐specific genes from shape genes, whereas Nova Scotia M. trossulus populations and SW England M. edulis × M. galloprovincialis populations exhibited an association between taxon‐specific genes and shape genes. We found no evidence of a geographic effect (NE versus NW Atlantic) for shape variation, indicating that the genotype effect is stronger than any geographic effect at macrogeographic scales. Pronounced differences were observed in trait variability consistent with an association between taxon‐specific genes and trait genes in European populations, and trait divergence of New York M. edulis from all European mussels. Trait variability in mussels from Newfoundland, Nova Scotia and northern Quebec indicated an uncoupling of taxon genes from trait genes, whereas trait variability in SW England M. edulis × M. galloprovincialis populations was consistent with background genotype, indicating a strong association between taxon genes and trait genes. A pronounced macrogeographic split (NE versus NW Atlantic) regardless of taxonomy was observed, indicating that geography exerts a greater influence than genotype on trait variation at the macrogeographic scale. This is consistent with pronounced within‐taxon genetic divergence, indicative of different selection regimes or more likely of different evolutionary histories of mussels on either side of the North Atlantic. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 96 , 875–897.     

Development of seawater tolerance and subsequent downstream migration in wild and stocked young‐of‐the‐year derived Atlantic salmon Salmo salar smolts

This study investigated the development of hypo‐osmoregulatory capacity and timing of downstream migration in wild Atlantic salmon Salmo salar smolts from the River Stjørdalselva and stocked young‐of‐the‐year (YOY), derived S. salar smolts from the tributary River Dalåa. Both wild and stocked S. salar smolts developed seawater (SW) tolerance in early May, persisting through June, measured as their ability to regulate plasma osmolality and chloride following 24 h SW (salinity = 35) exposure. Although the majority of downstream migration among the stocked S. salar smolts occurred later than observed in their wild counterparts, the development of SW tolerance occurred concurrently. The wild S. salar from Stjørdalselva and stocked YOY smolts from the River Dalåa started to migrate on the same cumulative day‐degrees (D°). The study revealed no downstream migration before development of SW tolerance. This emphasizes the importance of incorporating physiological status when studying environmental triggers for downstream migration of S. salar smolts. Overall, these findings suggest that the onset of smolt migration in stocked S. salar smolts was within the smolt window from an osmoregulatory point of view.     

Yield responses of Nepalese spring wheat (Triticum aestivum L.) cultivars to inoculation with Azospirillum spp. of Nepalese origin

Azosprilla were collected in wheat fields from subtropical and temperate soils of central Nepal at various elevations. Different wheat cultivars responded positively and significantly in grain yield, grain N-yield, and total N-yield in plant shoots to the inoculation with Nepalese isolate Azospirillum 10SW. Nepalese wheat cv. Seto responded significantly better with Azospirillum 10SW than with the Brasilian isolate A. lipoferum Sp 108 st, a strain which was found highly efficient in earlier experiments with German wheat cultivars, especially cv. Turbo. Yield of Turbo was increased by inoculations of both Azospirillum strains too, but it showed no significant differences depending from the inoculum used. The higher efficacy of combining Azospirillum 10SW and Seto, both collected from the same locality, indicates the possibility of improved associations using traditional cultivars and local bacteria. ei]{gnR O D}{fnDixon}     

Molecular phylogeny and biogeographic history of the European Maja spider crabs (Decapoda, Majidae)

We have assessed for the first time the phylogenetic relationships and biogeographic history of the crabs of the genus Maja that inhabit European coasts: M. brachydactyla, M. crispata, M. goltziana and M. squinado. Using mitochondrial markers, we have recovered a well-resolved phylogenetic tree that supports a single origin for the European species, most likely from an Indo-West Pacific ancestor during the Early Miocene. In this phylogeny, M. goltziana appears as the basal European species, with a sister lineage bifurcating into an Eastern Atlantic (M. brachydactyla) and a Mediterranean (M. crispata and M. squinado) clade. We propose the Tethyan Seaway as the initial colonization route, although an entrance through South Africa cannot be discounted. The Eastern Atlantic/Mediterranean split seems to predate the Messinian salinity crisis, which, in turn, could have promoted the recent divergence within the Mediterranean. In addition, Pleistocene glaciations could explain the current diversity in the Eastern Atlantic Ocean, where a unique mitochondrial lineage is found. According to this, the genetic profile of South African crabs appears to belong to M. brachydactyla, questioning the validity of the putative species M. capensis.     

Physiological preparedness and performance of Atlantic salmon Salmo salar smolts in relation to behavioural salinity preferences and thresholds

This study investigated the relationships between behavioural responses of Atlantic salmon Salmo salar smolts to saltwater (SW) exposure and physiological characteristics of smolts in laboratory experiments. It concurrently described the behaviour of acoustically tagged smolts with respect to SW and tidal cycles during estuary migration. Salmo salar smolts increased their use of SW relative to fresh water (FW) from April to June in laboratory experiments. Mean preference for SW never exceeded 50% of time in any group. Preference for SW increased throughout the course of smolt development. Maximum continuous time spent in SW was positively related to gill Na⁺, K⁺‐ATPase (NKA) activity and osmoregulatory performance in full‐strength SW (measured as change in gill NKA activity and plasma osmolality). Smolts decreased depth upon reaching areas of the Penobscot Estuary where SW was present, and all fish became more surface oriented during passage from head of tide to the ocean. Acoustically tagged, migrating smolts with low gill NKA activity moved faster in FW reaches of the estuary than those with higher gill NKA activity. There was no difference in movement rate through SW reaches of the estuary based on gill NKA activity. Migrating fish moved with tidal flow during the passage of the lower estuary based on the observed patterns in both vertical and horizontal movements. The results indicate that smolts select low‐salinity water during estuary migration and use tidal currents to minimize energetic investment in seaward migration. Seasonal changes in osmoregulatory ability highlight the importance of the timing of stocking and estuary arrival.     

The North Atlantic subpolar gyre and the marine migration of Atlantic salmon Salmo salar: the ‘Merry‐Go‐Round’ hypothesis

One model for marine migration of Atlantic salmon Salmo salar proposes that North American and southern European stocks (<62° N) move directly to feeding grounds off west Greenland, then overwinter in the Labrador Sea, whereas northern European stocks (>62° N) utilize the Norwegian Sea. An alternate model proposes that both North American and European stocks migrate in the North Atlantic Subpolar Gyre (NASpG) where S. salar enter the NASpG on their respective sides of the Atlantic, and travel counterclockwise within the NASpG until returning to natal rivers. A review of data accumulated during the last 50 years suggests a gyre model is most probable. Freshwater parr metamorphose into smolts which have morphological, physiological and behavioural adaptations of epipelagic, marine fishes. Former high‐seas fisheries were seasonally sequential and moved in the direction of NASpG currents, and catches were highest along the main axis of the NASpG. Marking and discrimination studies indicate mixed continental origin feeding aggregations on both sides of the Atlantic. Marked North American smolts were captured off Norway, the Faroe Islands, east and west Greenland, and adults tagged at the Faroes were recovered in Canadian rivers. Marked European smolts were recovered off Newfoundland and Labrador, west and east Greenland, and adults tagged in the Labrador Sea were captured in European rivers. High Caesium‐137 (¹³⁷Cs) levels in S. salar returning to a Quebec river suggested 62·3% had fed at or east of Iceland, whereas levels in 1 sea‐winter (SW) Atlantic Canada returnees indicated 24·7% had fed east of the Faroes. Lower levels of ¹³⁷ Cs in returning 1SW Irish fish suggest much of their growth occurred in the western Atlantic. These data suggest marine migration of S. salar follows a gyre model and is similar to other open‐ocean migrations of epipelagic fishes.     

Distribution,abundance, and feeding of a disjunct population of lady crab in the southern Gulf of St. Lawrence,Canada

The lady crab (Ovalipes ocellatus) is one of the most common native species of swimming crab (Portunidae) of the Atlantic Coast of North America but most populations occur south of Cape Cod, Massachusetts. There is a disjunct population in Northumberland Strait (southern Gulf of St Lawrence), which was the focus of this study. Adult lady crabs were collected by trawling in water >4 m deep from May to October 1999 to 2005 to determine abundance, distribution, and diet. Lady crab occurred only in a small area (about 2,500 km²) in the central part of Northumberland Strait where bottom water temperature was >18°C during summer, and the substrate was mainly sand or sandy gravel. Male lady crab attained a maximum carapace width (CW) of 112 mm compared to 92 mm CW for females. The summer and autumn diet consisted mainly of infauna. The principal prey (each >5% of diet by weight) were: small bivalve molluscs (primarily Atlantic razor clam Siliqua costata and Macoma sp.; 43%), small rock crab (Cancer irroratus; 13%), polychaetes (11%), fish remains (9%), and small lady crab (9%). All stomachs collected during May (water temperature ≤10°C) were empty. There was little evidence of any difference in feeding intensity between 0700 h and 1900 h.     

Morphometric comparison between Mediterranean and Atlantic populations of Pontophilus norvegicus (Decapoda, Crangonidae)

A multivariate comparison of morphometric differences was undertaken on populations of Pontophilus norvegicus from four Atlantic and one Mediterranean locations. Multiple discriminant analysis revealed clear morphometric differences between Atlantic and Mediterranean populations, with the Atlantic populations exhibiting a low degree of separation. The underlying variables responsible for this discrimination are shown not to have any operational taxonomic utility and, hence, no sub-specific status is attached to the respective populations.