The morphology and infraciliature of two planktonic marine ciliates, Cyclotrichium cyclokaryon, type species of the genus and C. taniguchii sp. nov. were investigated on live and protargol-impregnated specimens collected from the Jiaozhou Bay at Qingdao, China. Based on the present as well as previous studies, an improved diagnosis for the poorly defined genus Cyclotrichium is suggested: Didiniidae with ovoid to barrel-shaped body; cell-surface densely ciliated except in the domed proboscis region; anterior ends of kineties with long cilia forming one circumoral wreath of pectinelles; one circumoral kinety composed of a zig-zag structure; dorsal brushes absent. Cyclotrichium taniguchii is distinguished from its congeners by the combination of the following features: ellipsoid body shape, marine habitat, details of ciliature, and lack of a posterior tuft. Based on the characters of the ciliary pattern, a new genus, Dicyclotrichium gen. nov., with the type species Dicyclotrichiumsphaericum comb. nov. is established. The new taxon differs from Cyclotrichium by having two wreaths of pectinelles. Two known morphotypes are suggested to be assigned into this genus: Dicyclotrichium faurei comb. nov. [basionym: Askenasia faurei] and D. humilis comb. nov. [basionym: Askenasia humilis].

This investigation constitutes the first study of the serotoninergic nervous system in calanoid copepods (crustaceans). Serotonin (5-HT), a neurotransmitter which plays a part in many biological processes, has been detected by immunofluorescence in the brain, the circumoesophageal collar and the ventral nerve cord of the marine species Centropages typicus.

The vertical distribution of the hydromedusa Aequorea ?forskalea was investigated using observations from the research submersible ‘Jago’ collected during 36 dives off the west coast of southern Africa during November 1997 and April 1999. The mean population depth of Aequorea ?forskalea deepened with increasing sea surface temperature. We suggest that this behaviour enables individuals to avoid offshore advection, to minimize spatial overlap with other large medusae and to maintain their position over the middle of the shelf.

a shark tagging programme along the portuguese coast was initiated in 2001 in collaboration with the national marine fisheries service. from a total of 168 blue sharks (prionace glauca) tagged, 34 sharks were recaptured (20% return rate) providing important information on this species' movement patterns for the area. a total of 28 sharks travelled less than 1000 km while at liberty for time periods ranging from 22 to 1294 days. the remaining fish travelled long distances to north-west africa, central atlantic and the bay of biscay. only one shark made a transatlantic migration, being recaptured 3187 km from the tagging site. north–south movements seem to be related to seasonal sea-surface temperature variation in the north-east atlantic. seasonal segregation of different life stages also occurs.

Sphaerotylus antarcticus is a common Antarctic sponge characterized by a dense spicule fur that covers its surface. This sponge has been sampled at Terra Nova Bay from 22 November 2001 to 29 January 2002 at weekly intervals. On its spicules, a rich assemblage of benthic diatoms has been observed, mainly composed of Hyalodiscus sp., a centric sessile diatom, forming short colonies. The temporal trend of the abundances of these diatoms showed a maximum of 115×106 cells g−1 dry weight (dw) at the end of December. Almost all the diatom frustules observed in the sponge choanosome belonged to the planktonic species Fragilariopsis curta, which displayed a peak (50×106 cells g−1 dw) in the second half of January. Diatoms that were observed in the choanosome were of a size comparable to that of the inhalant pores, suggesting that sponges actively engulf diatoms, due to the pumping activity of their choanocyte chambers. Sponges, as active filter feeders, therefore represent one important vector in the transfer of energy from planktonic to benthic trophic chains in Antarctic habitats.

A molecular assay was designed to distinguish the common sea louse Caligus elongatus from its sympatric relatives. The method identifies the parasites at all developmental stages. Fragments of the mitochondrial Cytochrome C Oxidase 1 (COI) gene from identified adult caligids were amplified by polymerase chain reaction (PCR) and sequenced. Analysis of sequence data from unknown samples permitted identification by clustering of the samples with their appropriate genetic relative. Nucleotide sequences obtained were used for preliminary investigations of the population genetic structure of Caliguselongatus. Aligned sequences from the COI gene from this speciesindicate that our C. elongatus material divides into two distinct clades, possibly revealing two closely related species. The two genotypes do not appear to be associated with sample site, parasite gender, sample time or host species. Parasites from both groups were found on Atlantic salmon (Salmosalar), sea trout (Salmotrutta), pollack (Pollachiuspollachius), saithe (Pollachiusvirens), and Atlantic herring (Clupeaharengus).

Some examples of relationships between hydroids and epibionthic diatoms from the Mediterranean Sea are described, verifying the kind of interaction existing between the two partners. The athecate Eudendrium racemosum hosts an extremely rich diatom assemblage, mainly comprising Licmophora spp., Amphora spp. and Cocconeis spp. On the contrary, only adnate growth forms (Cocconeis pseudonotata, C. dirupta) were observed in diatom communities growing on the external side of thecate species Campanularia hincksii, Clytia linearis and Synthecium evansi. Some diatom species (Cocconeis notata, Cylindrotheca sp. and Navicula sp.) are able to survive in the intrathecal microenvironment. They live in the narrow space between hydrotheca and polyp, receiving protection and probably using the nutrients produced by hydroid metabolism. Sunlight can penetrate through transparent thecae and reach the diatom layer, making photosynthesis possible.

Benthic microalgal communities usually make a major contribution to the primary production of estuaries and shallow seas. Pulse amplitude modulation (PAM) fluorometry was used to investigate the contribution of benthic microalgae to the primary production of the Okhotsk Sea coast and Saroma Ko Lagoon in northern Hokkaido. In general the benthic communities had a relatively high biomass but low photosynthetic activity. This led to estimates of 29·2% and 64·5% for the benthic contributions for the 9 m and 3 m depth sites at Mombetsu and 13·1% for Saroma Ko. Sea ice algae provided the greatest contribution at Saroma Ko.

Six specimens of an unknown Argulus species were found on a cod caught off the coast of Finnmark in northern Norway. All six were found to be sixth stage male larvae, ∼2·6 mm long and 1·6 mm wide. Argulus has not previously been recorded from cod and this is also the first record of a marine Argulus from Norwegian waters. The Argulus sp. from cod can be easily distinguished from other marine species found in northern European waters, and also from Norwegian freshwater species of Argulus. It is believed that it represents a new species, but a complete species description must await the finding of adult stages.

Coelenterates (cnidaria and ctenophores) are well recognized as predators in food webs of marine ecosystems but are less often considered as prey. This is partly because they are digested very rapidly. In studies based on predator stomach contents the measured masses of different prey organisms are rarely scaled by their relative rates of digestion. Predators that are frozen and thawed, or for which whole stomachs are placed in preservatives, may have already lost much of their coelenterate content when they are examined. There is also a tendency to assume that gelatinous organisms, with their high water and salt content relative to organic content, are poor food. However, given the high rates of digestion (and presumably of assimilation) coelenterates may provide sources of energy comparable to better recognized prey such as arthropods. It is already becoming well documented that a number of cnidaria and ctenophores as well as fish utilize gelatinous organisms as prey. Data is accumulating more slowly on predation by a wide range of other carnivores such as molluscs, arthropods, reptiles and birds.

The distribution and abundance of benthic megafauna in areas known to be inhabited by dense gorgonian coral assemblages were examined at Northeast Channel, off Nova Scotia, Canada, in August 2001. Using a remotely operated vehicle, 1–5 video transects during each of 1–2 dives at each of four sites (Rips, Middle Canyon, Hell Hole West and Hell Hole East) were conducted. The relationships in the structure of biological assemblages at three spatial scales: within transects (10s of metres); between dive locations (100s of metres); and among sites (10s to 100s of kilometres) were explored. The most abundant epibenthic taxa included the gorgonians Primnoa resedaeformis and Paragorgia arborea, several suspension feeders (Actinauge verrilli, Bolocera tudiae, an unidentified anemone and encrusting sponge, Ophiacantha abyssicola), the deposit feeder Porania pulvillus insignus and the predatory Solaster endeca. The basket star Gorgonocephalus arcticus was present only on colonies of Paragorgia arborea. Despite large variability in abundance and assemblage composition among transects and dive locations, clear patterns were observed among sites. Mean abundance of most cnidarians and echinoderms was greatest at Hell Hole West. No gorgonians were found at Hell Hole East. The encrusting sponge was most abundant at the Rips and least abundant at Hell Hole East. Cluster analysis and multidimensional scaling (MDS) indicated that, when abundance was averaged across transects for each dive, the megafaunal assemblages fall into groups of dives that separated by site. These differences among sites are most likely related to variability in the physical environment. The epibenthic megafaunal assemblages were as diverse in the presence as in the absence of gorgonian corals, at least at the abundances that we observed. However, the apparent low recruitment and abundance, combined with small population size make these assemblages particularly vulnerable to perturbations.

A new species of the cosmopolitan genus Eudendrium, E. klausi, is described from Carrie Bow Cay, Belize. The species is characterized by a small colony with an intense blue colour, polyps armoured with large microbasic euryteles scattered on the hydranth body, hypostome, and female spadix; female gonophores on normal hydranths with a reduced number of tentacles. The new species is compared to other Eudendrium with similar cnidome, and other Caribbean species, including those described by Allman (1877). Among the latter, E. gracile, E. laxum, E. attenuatum, and E. tenellum (sensu Allman) are considered as species inquirenda due to the lack or the unsuitability of the type materials and the inconclusive original descriptions. Eudendrium exiguum, E. eximium, and E. fruticosum were also studied and demonstrated to be different from E. klausi sp. nov.

The genus Heterogorgia is reported for the first time from the shallow waters of the Galápagos Archipelago, and a new species found in the southern islands is described. The new species is distinguished from the other species of the genus described thus far by having thick branches with large, densely packed calyces, being mostly unbranched, and having larger sclerites. The occurrence of Heterogorgia verrucosa is also reported.

specimens of the zipper sand skate psammobatis extenta were collected in the region of ubatuba off the northern coast of the state of são paulo, brazil, monthly for one year (january–december 2000), at 25- to 40-m isobaths. a total of 123 individuals were caught. the total length (tl) of females averaged 224.6 mm, and of males 217 mm. the overall sex ratio was 1:1. analysis of the length–weight relationship indicated the existence of positive allometry in females, and isometry in males. the length at onset of sexual maturity was determined for both sexes; females reached sexual maturity at smaller sizes than males (tl50=230.7 and tl50=237.7 mm respectively). females showed functional parity of both ovaries and uteri. females that were pregnant or were carrying vitellogenic oocytes were observed during nine of the 12 months of the survey, indicating a continuous reproductive cycle. psammobatis extenta was most abundant from january to april, and again from june to october. most individuals were collected at the 40-m isobath. both adults and neonates were collected in the study area. however, adolescent skates were scarce, which either indicates differential occupation of the area, or suggests that the shallow waters of the continental shelf are used as breeding grounds.

The edible cockle (Cerastoderma edule), a common marine bivalve in semi-sheltered sandflats, is a natural host for many parasite species of the genus Himasthla (Echinostomatidae: Trematoda). In a previous paper, Wegeberg et al. (1999) showed segregation of cockle infection by three Himasthla species (H. interrupta, H. continua, H. elongata) in relation to host tissue (foot, mantle, siphon) and host size (1·5 to 14 mm shell length). Following the same experimental procedure, a fourth species, H. quissetensis, an introduced dominant parasite of cockles in Arcachon Bay (south-west France) was investigated. The infection pattern was very similar to the patterns shown by H. elongata and H. continua. Cercariae (the free-living stage shed from prosobranch snails and encysting as metacercariae in bivalves) were most successful in the shell-length range of 6–14 mm, where 74% of the added cercariae were recovered as metacercariae. The comparison with the other Himasthla species supports the previous conclusion that the efficiency of cercariae to infect cockles depends on host size.

the presence of velvet belly, etmopterus spinax in angolan waters is confirmed by the capture and examination of 233 specimens caught between 2002 and 2004 on board the rv ‘dr. fridtjof nansen’. morphometric measurements are given.

The trophic ecology and seasonal changes in the diet of the intertidal hydrozoan Tubularia crocea were studied analysing the enteron contents of hydranths collected each season of the year. The relationship between feeding rate, prey availability, and re-suspension processes caused by tidal currents was also assessed. The most prevalent food items were diatoms and crustaceans. The most remarkable differences occurred during summer, when crustaceans were more abundant than diatoms. Conversely, diatoms were the most abundant prey during other seasons, and they were almost the only prey found during winter. There was no relationship between abundances of primary prey items in the water column and their occurrences in stomach contents. Instead, most prey items consisted of benthic organisms, primarily two species of diatoms (Grammatophora marina and Licmophora abreviatta) and fragments (usually appendages) of the amphipods Caprella sp. and Jassa falcata. Most food items were digested within 4–4·5 hours. The mean number of items captured per polyp per day was determined to be 115·2±19·2 in summer, 93·6±14·4 in autumn, 76·8±21·6 in winter and 199·2±31·2 in spring. Prey biomass (dry weight) polyp−1 d−1 was 5·1 μg in summer, 2·3 μg in autumn, 1·8 μg in winter, and 6·3 μg in spring. These values, in relation to hydranth biomass (55·3 μg; dry weight), were equivalent to a food intake polyp−1 d−1 of 9·3%, 4·2%, 3·2% and 11·5% of its own weight, respectively.

Two new marine species of Gastrotricha: Chaetonotidae are described from West Greenland and Denmark. Some peculiar features suggest the affiliation of the two species to a new genus, for which the name Diuronotus is proposed. The affinity of these gastrotrichs with species of Musellifer, the only genus entirely marine and hermaphroditic, and possibly the most basal one along the Chaetonotidae evolutionary line, is discussed from a morphological point of view. The span of the geographical distribution of Diuronotus is discussed in the light of a record of an additional co-generic, undescribed species from the USA. The relationships of this genus will be important in reconstructing the evolutionary pathways within Gastrotricha: Chaetonotida.

Qualitative composition and abundance of both ichthyoplankton and small forms of zooplankton were evaluated by field studies in the northern (the Crimea near Sevastopol) and southern (Sinop region and TEEZ) Black Sea during the summers 2000 and 2001. A tendency of increasing the species richness, abundance of fish eggs and larvae as well as zooplankton (which is the food for fish larvae) was observed over a period of Mnemiopsis leidyi and Beroe ovata co-existence. The eggs and larvae of the Mediterranean migrants—bonito and bluefish appeared again in the coastal waters near Sevastopol, which testified to favourable conditions for the spawning and nutrition of these fish species and their larvae. Aborigen copepod Oithona nana was found in the Crimean coastal waters although earlier in the 1990s it had completely vanished. Although rare in the 1990s copepods Centropages ponticus and Paracalanus parvus appeared in inshore waters as well as Pontellids species. Observed increases in species number and abundance of both ichthyoplankton and small zooplankton (≤500 μm), which promoted survival and development of fish larvae, were attributed to reduced predatory impact of Mnemiopsis on prey zooplankton after the arrival of Beroe in the late 1990s. However, the influence of Mnemiopsis continued to be significant during the short period of its peak occurrence in late summer. When this period coincided with the appearance of fish larvae, a negative impact on their survival could be predicted due to a low concentration of food items for larvae feeding.

Mobile lice levels of two species of sea lice, Lepeophtheirus salmonis and Caligus elongatus, were examined on two samples of Atlantic salmon from the west coast of Ireland. The samples examined were taken two weeks apart from salmon caught by drift net in June 2003 at two different locations off the west coast of Ireland, one in the north-west and one in the west. Both samples of salmon caught were comparable in terms of numbers of total lice counted. No significant differences in male, female and ovigerous L. salmonis levels between the two samples were recorded, however, a significant difference was recorded between juvenile L. salmonis levels. Morphometric comparisons of male and ovigerous L. salmonis examined for each of the two salmon samples examined revealed some differences. There was a significant difference in male L. salmonis in terms of cephalothorax length between the samples. In the females significant differences were found between cephalothorax length, overall total length and egg length. Significant positive correlations within samples were also observed, between total female body length and both total egg number and egg string length in one of the samples examined.