The newly introduced red alga Heterosiphonia japonica, previously denoted as Dasysiphonia sp., has, since its first record in Europe in 1994, established populations in the Netherlands, Spain, France and Norway. In order to investigate the geographical distribution of the species along the Norwegian southwest coast, 83 localities were dredged along a total distance of 830 km, and the abundance of H. japonica recorded on a semi-quantitative scale in 2000-2001. H. japonica was present in the entire range investigated. The local abundance of H. japonica at 40 localities in an area south of Bergen was recorded by dredging. H. japonica was not present at wave-exposed localities, but was abundant at the more sheltered localities where it could constitute Lip to 65% of the total algal content of the dredge. The size distribution in a population was also studied at one locality during I year. Plants in good condition were found throughout the year and a large number of plantlets were present during all seasons. The results of this study suggest that the species has a high dispersal and recruitment capacity. The effect of H. japonica on indigenous ecosystems has yet to be determined.
Deterioration of an eelgrass (Zostera marina) bed was observed in Skagerrak, southern Norway in August 2002. Compared with observations from previous years, there was a significant reduction in canopy height and shoot density. Simultaneously, high numbers of the gastropod Rissoa membranacea were observed. The proposed mechanism for this drastic loss of eelgrass leaves involves epidermal injuries caused by the grazing activity of the numerous snails, with subsequent leaf breakage. After 1 year, the canopy height had recovered, but shoot density was at the same level as in 2002.
Until recently, the pelagic family Yndolaciidae was considered to include a single genus and species Yndolacia lopadorrhynchoides Stop-Bowitz, 1987 from the Gulf of Guinea. Yndolaciella polarsterni gen. et sp. nov. and Paryndolacia tomopteroides gen. et sp. nov. are described from the deep sea of the Arctic Ocean. Additions and refining of the diagnoses of the genus Yndolacia and the family are given. The absence of cephalic tentacles, a weakly developed brain, simple biramous parapodia with equal rami, similar cirri without cirrophores, a superficial position of the nervous system, the presence of two nerve cords and the lack of ganglionic swellings are assumed to constitute ancestral characters of the family. Some resemblance of the family to Tomopteridae is noted. It is supposed that fossil polychaete Eotomopteris aldridgei Briggs & Clarkson, 1987 belongs to Yndolaciidae.
Blood from 1209 individual cod was sampled from nine localities in the Northeast Atlantic, and analysed using agar gel electrophoresis (AGE) and isoelectric focusing (IEF) to reveal individual and population variation in haemoglobin genotypes. The second aim of the study was to compare our data with data collected some 30 years ago in the same area to investigate possible directional selection. A new haemoglobin polymorphism of Atlantic cod was documented in samples from Danish waters using IEF electrophoresis (pH 5.5-8.5) and, in addition to the five genotypes seen in earlier studies, 11 subtypes are described. Significantly different genotype distributions were found between the samples from northern Norway on the one hand and southern Norway and Danish waters on the other, and the frequency of the Hb-1(1) allele increased from north to south. With the possible exception of two samples, the frequency of the main haemoglobin genotypes was found to be very similar to corresponding frequencies described in these areas three decades ago. The frequencies of the Hb-1 subtypes off Norway varied among the sampling sites and were only found in Norwegian coastal cod with increasing frequency from north to south. In the Danish samples, 11 novel Hb-1 subtypes were found and are described.
As part of the BIOFAR I programme 1987-1990, qualitative analyses of gastrotrichs have been carried out on samples of primarily carbonate sediment collected at the Faroe Bank. The taxonomic composition was examined and studies with respect to morphology performed. In total, 20 species, belonging to three macrodasyidan families and one chaetonotidan family, were recorded: Dactylopodolidae (three), Lepidodasyidae (three), Thaumastodermatidae (12), Chaetonotidae (two). Six new species are described: Lepidodasys arcolepis sp. nov., L. castoroides sp. nov., Tetranchyroderma faroense sp. nov., Thaumastoderma moebjergi sp. nov., Pseudostomella faroensis sp. nov., and Ptychostomella higginsi sp. nov. A seventh species, Platydasys sp. 1, is also probably new. Platydasys brachycephalus Lévi is transferred to the genus Ptychostomella Remane. The subspecies Diplodasys ankeli pacificus is given the rank of species.
This study focused on the reproductive biology of the velvet swimming crab, Necorapuber (L.), and its implications for managing the fishery in the Orkney Islands, UK. According to gonadal observation, 50% of the population became sexually mature at 43.8 turn carapace width (CW) for females and 52.8 turn for males. Ovigerous females were observed from January to July, with peak occurrence in spring. Clutch size (N) ranged from 5000 to 278,000 eggs, and was related to CW by the equation: N x 10(3) = 0.0026 X CW2.5169, displaying considerable variability, possibly due to the fringe location of the population related to its general species distribution. Reinstatement of the closed season, coinciding with the peak moulting period, is recommended. The minimum landing size is appropriate for the population in terms of sexual maturity. The common practice of discarding recently moulted and ovigerous individuals should be incorporated into the fishing regulations.
A high number of red king crabs, Paralithodes canaschaticus, captured in the Norwegian commercial trap fishery have to be returned to the sea because they are females or sublegal males. In the present study, a comparative fishing trial was performed to investigate whether escape openings in traps lead to lower catches of small king crabs. Traps equipped with circular escape openings with an inner diameter wider than 160 mm retained legal crabs, while catches of sublegal male crabs became significantly reduced. Small female king crabs had a lower escape rate front traps with escape openings than small males.
Two new species of cheilostome Bryozoa are described: Pentapora boreale sp. nov. and Microporella svalbardensis sp. nov. Both are illustrated using scanning electron microscopy. The genus Pentapora is recorded for the first time from the Arctic realm. Pentapora boreale is especially characterized by a columnar umbo present proximal to the primary orifice and a straight‐edged lyrula developed just within the proximal border of the orifice. Microporella svalbardensis is distinguished by a large, crescentic ascopore, crossed by thin radial bars, with a prominent umbo situated just proximal to it. Colonies of both species encrusted pebbles, and M. svalbardensis occurred additionally on biogenic carbonate substrata.
Marenzelleria is revised on the basis of material from the Arctic, North America, Europe and the Far East. Types of all species included in the genus are examined. Five species are registered. Marenzelleria neglecta sp. nov. is described from the coastal waters of the southern Baltic. Two species, M. arctia and M. wireni, occur in the Arctic, whereas M. viridis and Marenzelleria sp. A are found in coastal waters of the Atlantic. Marenzelleria neglecta occurs both in arctic and boreal estuaries. Complete description of Marenzelleria sp. A must await additional material. A generic diagnosis and a key to the species are given.
Soft-bottom macrofauna were sampled quantitatively in August 1994 in three undisturbed north Norwegian fjords. Samples were taken at 10, 25, 50 and 90 in depth in each fjord. The total number of taxa recorded was 399 and the number of specimens 221,017, inclusive of ten juvenile taxa with 1265 specimens, collected from a told sampling area of 4.8 m(2). The number of taxa per station varied from 75 to 171, the density from 1790 to 8723 individuals m(-2), and the faunal diversity (Shannon-Wiener H') from 4.4 to 6.4. In general, the number of taxa increased with depth, whereas the highest densities were recorded at 10 and 25 in. The species richness was generally high at both small (alpha diversity) and larger (gamma diversity) spatial scales compared with other northern and off-shore shelf areas. Species turnover (beta diversity) was,greater across depths within fjords than within depths across fjords. Species community patterns were related to depth and sediment grain size. Statistical analyses undertaken indicated that the juveniles did not affect community structure very Much. Among the polychaetes and molluscs the proportion Of surface deposit feeders - inclusive of the both surface-feeding and suspensivorous Spionidae and Oweniidae - and the deep Subsurface deposit feeders (Maldanidae and the capitellid Heteromastus filiformis) largely increased with depth. The lowest proportion of other subsurface deposit feeders and the suspensivores occurred at the deepest stations. The study may provide useful reference data for sub-Arctic fjord enviroinments.
To investigate the influence of substrate composition on burrowing depth and respiratory funnel diameter. two species of irregular sea urchins (Spatangoida) were allowed to burrow in different substrates in laboratory experiments. The maximum burrowing depth and respiratory funnel diameters were measured. Both are dependent on substrate composition. In muddy sand the burrowing depth of Echinocardium flavescens (O. F. Muller 1776) increased as the proportion of mud in the sediment increased. The diameters of respiratory funnels were significantly smaller where the proportion of mud exceeded 50%. An exhalation current was visualized using a rhodamin solution. In Echinocardium flavescens and Brissopsis lyrifera, the exhalation current reaches the sediment surface posterior to the echinoid through a number (three to six) of small tubes.
An exposed sandy beach located at Sylt was studied to analyse the patterns in the number of major taxa, abundance, biomass, and zonation of meiofauna. Three sites with different morphodynamic states were sampled. The results of a canonical correspondence analysis showed that water content, porosity and grain size were the best predictor variables of meiofaunal density. The highest meiofaunal densities and biomass occurred at the mid-shore levels of each site: up to 9592 individuals 10 cm(-2) and 7.5 g m(-2) (ash-free dry weight) at the reflective site, 11,640 individuals 10 cm(-2) and 9.4 g m(-2) at the low intermediate site, and 2993 individuals 10 cm(-2) and 1.5 g m(-2) at the mid-intermediate site. The total abundance and biomass of the meiofauna per running metre of beach were higher at the low intermediate site (141 x 10(6) individuals m(-1) and 98 g m(-1)), compared with the reflective site (74 x 10(6) individuals m(-1) and 55 g m(-1)) and the mid-intermediate site (69 x 10(6) individuals m(-1) and 33 g m(-1)). The number of major taxa was nine, ten, and eight at the reflective, low intermediate and mid-intermediate sites, respectively. The across-shore variability in densities and community assemblage structure of the meiofauna decreased through the dissipative state.
Sub-fossil remains of macrofauna extracted from a 5.3m sediment core in the central part of Limfjorden indicate marked changes in salinity. Sub-fossils in the lower part of the core indicate marine conditions similar to those of the present North Sea, while the upper 2 m of the core represents periods of brackish conditions alternating with periods of intermediate salinity similar to the present condition, indicative of alternating opening and closure of the fjord to the west. Precise C-14 dating of changes is hampered by variable marine reservoir effects and the addition of old carbonate from ground-water runoff. Salinity indications from dinoflagellate cyst assemblages from this core, but published elsewhere, are in accordance with those from macrofauna assemblages.
A large new species of acoel belonging, to the genus Haploposthia (Acoela) is described. Haploposithia lactomacculata sp. nov. was collected by dredging from the Swedish west coast at depths of 45-55 ill. The main diagnostic features of the species are a whitish translucent body with opaque white or milky Clot pigmentation oil the dorsal side around the midbody. epidermis with a smooth surface, sclerotized Conical penis papilla, seminal vesical surrounded by accessory glands, mixed germinal centre for ovary and testis, and large size (2-3 mm).
In a period mainly from 1995 to 1998, 19 species of southern temperate and subtropical mesopelagic fish have been caught in Norwegian blue whiting, Micromesistius poutassou (Risso), surveys in the Rockall Trough area. Six of the species have not previously been recorded that far north, and the other 13 only rarely in adjacent waters. The species were of the following families: Stomiidae (four species), Microstomatidae (one species), Bathylagidae (one species), Opisthoproctidae (one species), Myctophidae (four species), Evermannellidae (one species), Nemichthyidae (one species), Derichthyidae (two species), Melanonidae (one species), Melamphaidae (one species), and Chiasmodontidae (two species). We discuss whether these range extensions are real and attributable to the recent ocean warming, or only apparent, caused by increased sampling effort.
The nudibranch species Tenellia adspersa (Nordmann, 1845) is recorded from the Finnish archipelago for the first time in more than 100 years, as previous records of this species from the Baltic proper are few and date back prior to 1900. The present record was made by means of SCUBA diving at near-shore brackish water locations. Despite only a few early records from the literature, the new data presented here suggest that this species is abundant in the northern part of the Baltic proper. A short account of ecological observations of T adspersa from the Northeast Atlantic is given, indicating that together with the present abundance, this highly adaptable species is fully capable of thriving in true brackish water conditions.
A field study was conducted in Santala Bay with weekly samplings during February and March 2000. Ice thickness was 20-28 cm, snow cover 0-1 cm. The under-ice water column was stratified with a cold (-0.3-0.2 degreesC) and less saline (S = 2.1-4.9) interface layer. Concentrations of particulate organic carbon (0.5-5.8 mg POC1(-1)) and algal pigments (0.3-18.2 mug chlorophyll a1(-1)) were higher in the ice than in the water (0.2-0.5 mg POC1(-1), 1.6-7.1 mug chlorophyll a1(-1)) and peaked mostly in the bottom part of the ice. The thin ice and almost lacking snow cover had favoured an early ice-algal and phytoplankton bloom. The diversity of metazoans was low, with six species in the ice and eight species in the under-ice water. The rotifer Synchaeta cf. littoralis dominated both in ice and water, with maximum abundances of 230 individuals 1(-1) in the bottom part of the ice. Rotifer eggs were also observed in the ice. Baltic sea ice seems to be a suitable habitat for rotifers. Nauplii and copepodids of the calanoid Acartia longiretnis in the under-ice water showed some herbivorous feeding (<0.1-0.23 ng gut pigluent individual(-1)), but analysis of fatty acids, fatty alcohols and biomarker ratios indicated a more omnivorous/carnivorous diet. Despite low temperatures, this copepod showed growth and development below the ice, doubling in numbers (mainly CI, CII) from 118 to 230 individuals m(-3) during the third week of March.
This paper presents an analysis of zooplankton composition and abundance based on sampling over the depth range 0-50 m at nine transects (61 stations) during a hydrobiological survey of Icelandic waters in May-June 1992. Zooplankton abundance and species distribution is considered in relation to water masses and topography. The biomass of zooplankton was highest in the oceanic areas northeast of Iceland [similar to8-20 g dry weight (dw) m(-2)], whereas the lowest values were generally observed in the offshore areas southeast, south and southwest of Iceland (< 2 g dw m(-2)). Over the shelves, the values tended to be intermediate (similar to2-5 g dw m(-2)). In total, 93 species and identification groups were identified in the samples. Calanus finmarchicus was by far the most abundant species [about half of the total numbers of zooplankton if Calanus spp. nauplii (similar to20%) are included]. Less numerous groups were Oithona spp., cirripede larvae, euphausiid larvae (nauplii, calyptopis and furcilia stages), larvaceans, Pseudocalanus spp., C hyperboreus, Acartia spp., and Temora longicornis. A cluster analysis was carried out in order to reveal relationships among stations in zooplankton abundance and species composition. The analysis classified stations into four groups, mainly defined by bathymetry and hydrographic conditions. In the coastal water south and west of Iceland, cirripede larvae were by far the most abundant group, followed by C.finmarchicus and euphausiid larvae (group A), while in the coastal water north of the country, C. finmarchicus, euphausiid larvae and larvaceans were most abundant (group B). In the offshore waters south of the island, C. finmarchicus, Oithona spp. and echinoderm larvae were most abundant (group C), whereas in the offshore area north of Iceland C. finmarchicus, Oithona spp. and C. hyperboreus were most abundant (group D).
The isopod species Syscenus atlanticus Kononenko, 1988, is recorded for the second time, from Bear Seamount off New England, western North Atlantic. The species, previously known only from the central North Atlantic, is redescribed, illustrated, and compared with the more common S. infelix Harger, 1881, which is also redescribed and illustrated. The distribution of S. infelix in a broad arc across the North Atlantic Ocean, based on 171 specimens from several museum collections, is discussed.
Genetic variation among and within species of the genus Sebastes [S. viviparus, S.fasciatus, S. mentella (including deep-sea and oceanic types) and S. marinas (both ordinary and giant types)] from the North Atlantic was investigated by polymerase chain reaction (PCR)-based random amplification of polymorphic DNA (RAPD). Initial analyses were based on 80 different 10 base pair primers applied to a small number of individuals of each of the four species. Four of the most variable primers were selected for analysis of the total samples from Norway, Iceland and Canada. Only one primer, OPA20, could be used to diagnostically distinguish among species. Statistical analysis clustered all samples in relation to known species structure. No genetic distance was found between ordinary and giant-type S. marinas and minor differences were observed between S. viviparus from Iceland and Norway. Sebastes mentella from the different locations clustered together, but some structuring was shown within this species. Twelve untyped Sebastes and S. fasciatus from Gulf of St. Lawrence clustered closer to S. viviparus than to S. marinus and S. mentella.
