The spatial patterns of distribution of five species of the Gerreidae (Diapterus rhombeus, Eucinostomus argenteus, Eucinostomus gula, Eucinostomus melanopterus and Eugerres brasilianus) in Mambucaba estuary, south-eastern Brazil, were determined to assess habitat partitioning of the estuarine reaches. Sampling was conducted between October 2007 and August 2008. Diapterus rhombeus and E. gula were exclusively found in the lower estuary, whereas E. melanopterus and E. brasilianus were exclusively found from the middle estuary. Eucinostomus argenteus was common in the two estuarine zones. Total length and total weight data showed that the smallest individuals of D. rhombeus and E. gula were found near to the estuarine mouth compared with deeper areas of high salinity and lesser influence of the estuarine plume. The smallest individuals of E. argenteus, E. brasilianus and E. melanopterus were found in a protected estuarine lagoon connected to the main estuarine channel, and the largest in the other sites in the main channel of the middle estuary. Spatial partition seems to be the strategy developed by the 5 members of the Gerreidae family to coexist in the Mambucaba estuary, which may be attributed to competition in the past between the species of Gerreidae or to differentiated tolerance to environmental constraints

The Ciliates described in this paper were mostly found living in the tanks at the Plymouth Laboratory, which are supplied with a constant circulation of sea-water from two large storage reservoirs. Most of them came from a large shallow tank standing in front of a south window, which is referred to in the paper as “Drake's Island Tank.”

The digestive gland of the tropical sepioid Idiosepius pygmaeus (Steenstrup) (Cephalopoda: Idiosepiidae) is characterized by a single cell type which secretes proteinaceous spherical bodies, the secretory spheres. Changes in the structure of the gland with feeding were investigated through a field sampling programme and a laboratory feeding experiment. Specimens were collected in the field on three consecutive days. There was a significant increase in the number of spheres during the day. A laboratory-based night trial showed that numbers of secretory spheres remained high during the night. After feeding there was a rapid and marked increase in the number of secretory spheres, suggesting that upon registering a stimulus the digestive gland secretes large amounts of enzymes. The process is rapid with an increase in the number of spheres occurred one hour after feeding. A second peak occurred 16 hours after feeding, suggesting that there may be two phases to the digestive cycle. This study examined natural and experimental patterns in the digestive gland and estimated the time involved in the digestive activity of I. pygmaeus.

Previous studies on the ultrastructure of barnacle cypris larvae suggest that cypris morphology, especially the antennules which play a key role in selecting the final substratum for settlement, may show variations between species existing in different habitats. In the present study, the cypris morphology of the barnacle Fistulobalanus (Balanus) albicostatus, which predominantly lives on trunks of mangrove trees was investigated using scanning electron microscopy and compared with that of species from other habitats that have already been described. The antennular segments II and III of F. albicostatus each bear one post-axial seta. The third segment consists of an attachment disc surrounded by a thin cuticular velum and the fourth segment exhibits four sub-terminal setae and five terminal setae. The morphology of the cypris antennules of F. albicostatus is similar to other balanomorph barnacles which inhabit hard shores, revealing that the antennular morphology does not have diagnostic variations between species from the different intertidal habitats. The morphology of the caudal rami (used in the evaluation of the substratum microtopography), however, appears to vary among barnacles living on different substrata.

The growth and size-structure of the bathyal ophiuroid brittle star, Stegophiura sp., were analysed from skeletal growth bands and disc diameter frequencies. Specimens were collected in trawl samples taken on the continental slope off central Chile (~36°S) at two sites within the recently discovered Concepción Methane Seep Area (CMSA) and at two control non-seep sites. Growth bands were measured as radii of vertebral ossicles from scanning electron microscope (SEM) micrographs and used to provide size-at-age data. The von Bertalanffy and the Gompertz growth models provided good fit to size-at-age data. The size-structure distributions observed in the study area suggest that small-bodied (<10 mm disc diameter) individuals of Stegophiura sp. are more abundant near seep sites, probably attracted there by the presence of methane-derived authigenic carbonates, which provide a preferred habitat for ophiuroids and benthic fauna in general. Furthermore, size-at-age data from measurements of the ossicle growth bands indicate relatively rapid growth of Stegophiura sp. populations at seep sites. Assuming that the growth rings are annual, the maximum Stegophiura sp. age was estimated to be 15 years. The growth performance of this species falls within the range of values reported for sub-Antarctic and bathyal species.

Large numbers of small individuals (pediveligers and juveniles <5 mm) are routinely recorded in size–frequency distributions of mussel samples collected from deep-sea chemosynthetic environments. If recruitment of invertebrates to deep-sea hydrothermal vent sites were via long-distance dispersal, as is typically assumed, one would expect recruitment ‘events’ recorded in size–frequency distributions to be difficult to detect, due to loss of larvae in an open system over large distances. If one imposes mesoscale oceanographic phenomena that minimize dilution of larvae (such as eddies shed from hydrothermal vent plumes) and episodic spawning, expression of this mesoscale corralling at the level of population structure would likely be limited to discrete records of recruitment events encountered serendipitously during haphazard sampling in space and time. The ubiquity of large numbers of post-larvae in mussel samples from a number of disparate sites is likely not serendipitous, but instead may reflect the importance of local sources and sinks of propagules in maintenance of mussel populations.

Home ranges of seven Guiana dolphins (Sotalia guianensis) (Van Bénéden, 1864) were studied in the Cananéia estuary (~25°03′S 47°55′W), south-eastern Brazil. Boat-based observations were conducted from May 2000 to July 2003 in ~132 km2 of protected inner waters. The photo-identification technique was used to follow naturally marked individuals through time and space. From a total of 138 catalogued individuals, five males and two females presented 20+ sightings and were used for home range estimation. Sightings were plotted and analysed in a Geographic Information System (GIS). With the ‘Home Range Tools’ extension the fixed kernel density estimator with band width (smoothing parameter) chosen via least squares cross-validation was performed for each individual. The fixed kernel method was used to estimate the non-parametric utility distribution of each dolphin, keeping band width (h) constant for a data set. The first polygons created by these parameters had an amoeboid shape and in some cases more than one centre of activity. The 95% home range estimated outlines varied from 1.6 to 22.9 km2 (7.9 ± 8.3 km2). This large interval shows strong evidences on individual variation in S. guianensis' home ranges. Several individuals showed small home ranges when compared to other cetacean species. An overlap of home ranges of different sizes and shapes were observed for Guiana dolphins with large range movements. Centres of activity were concentrated in the main entrance of the Cananéia estuary. This was a first attempt to understand the way S. guianensis uses the Cananéia estuary and such data are essential for conservation and management purposes.

A new member of the Haptophyceae, Corymbellus aureus gen. et sp.nov. is described. The cells of this species are aggregated into motile colonies which are more or less spherical at first, but which become annuloid as their size increases.

Individual cells are large and rather irregular in overall morphology with two heteroor homodynamic flagella and a short non-coiling haptonema arising from an anterior apical groove or furrow. Two types of oval body-scale are present; the larger, with upturned rim and a short central spine, are generally distributed, whilst the smaller, lacking such ornamentation, are confined to the apical groove.

Analyses of sea water collected during 1957 at the International Hydrographic Station E1 (lat. 50° 02′ N., long 4° 22′ W.) are given here in the same form as in earlier reports (Armstrong, 1954, 1955, I957> 1958). The methods of collection and of analysis for phosphorus and silicon are substantially unchanged. Some analyses were made for ammonia by a vacuum distillation method (Riley, 1953), and for inorganic nitrogen (nitrate + nitrite + ammonia) by reduction of nitrate and nitrite with nickel (Riley & Sinhaseni, 1957) to ammonia, which was vacuum distilled. Salinities were determined by the Government Chemist's Department.

We wish to express our thanks to Lt.-Cdr. C. A. Hoodless and the crew of R.V. ‘Sarsia’ and to Capt. W. J. Creese and the crew of R.V. ‘Sula’, for assistance at sea.

The present paper is the outcome of an investigation made on a species of Gammarus inhabiting both fresh and brackish water (4, p. 657). As this species (G. zaddachi) seemed to show a marked variation in appearance according to its environment, we instituted experiments in the Laboratory at Plymouth on G. chevreuxi to see if a similar variation in appearance could be brought about by varying the degree of salinity of the water in which the animals lived.

Fish catch composition in 21 gill net samplings performed between 2014 and 2015 at Rhodes Island (Aegean Sea, Greece) was analysed, with the aim to contribute in filling scattered information on coastal fish assemblages in a Mediterranean region heavily impacted by biological invasions. A total biomass of 183 kg was collected comprising 1070 fish individuals, distributed along 43 native and six Lessepsian migrant species. The alien Siganus luridus prevailed in terms of frequency of occurrence, followed by the native Sparisoma cretense, which exhibited the higher abundance and biomass, followed by S. luridus, Scorpaena scrofa and Siganus rivulatus. Ratios between alien and native species as well as between their abundance and biomass are discussed.

Oceanic and coastal bioluminescence in surface waters, in many instances, is produced by microscopic dinoflagellates. Their light emission is usually observed at a maximum during the night hours and markedly inhibited during the day. This diel periodicity has never been observed in situ for identified species and never before in heterotrophic Protoperidinium dinoflagellates. Pronounced differences in stimulable bioluminescence measured with bathyphotometers in Vestfjord, Norway in September 1990 correlated with simultaneous ship-board laboratory experiments. Cells of both the photosynthetic Ceratium fusus and heterotrophic Protoperidinium curtipes showed a pronounced inhibition of bioluminescence during the day and maximum bioluminescence at night.

Invasive species are leading to ecosystem changes and socioeconomic deterioration around the globe. In 2018, unknown soft corals were noticed forming a massive ‘blue carpet’ on a shallow reef environment at Todos os Santos Bay, South-west Atlantic. In this study we identified the species, quantified their distribution and abundance as a first step for baseline invasion monitoring, and discussed origin, vector and impacts on native competitors. Coral samples were identified based on morphology and a multilocus DNA barcode, and benthic structure was characterized using digital photoquadrats. Our results revealed two new harmful non-native octocorals in this tropical rocky reef, the ‘blue polyps’ genus Sarcothelia (Xeniidae), native to Hawaii but likely an undescribed cryptic species, and Briareum hamrum (Briareidae), native to the Indian Ocean. Sarcothelia sp. was the dominant taxon in the rocky reef (mean cover 23.66% ± 21.46), exhibiting high coverage as well in the sandy and patch reef habitats (15.83% ± 15.81), however, only three colonies of B. hamrum were found, all outside the sampling area. These octocorals were in physical contact with native benthic organisms, mainly with the most abundant group, but apparently avoid turf algae in sandy and patch reef habitats. We suggest that irresponsible marine aquarium releases likely introduced these species to Brazilian reefs. After identifying the aquarium trade as the main vector of octocoral introductions, we reinforce the importance of inspecting marine species importation and the urgent need to implement a government plan to mitigate invasive species' impacts on the natural reefs of Brazil.

Parasitism is increasingly recognized as an important determinant of population dynamics, productivity and community structure in intertidal ecosystems, and yet there is very little known about the effect of parasites on polychaetes, which represent a major component of the benthic fauna. We surveyed 11 polychaete species from a mudflat in Otago Harbour, New Zealand, and found that seven of these were infected by five parasite species: four trematodes and one apicomplexan gregarine. The gregarine found in Spirobranchus cariniferus and a strigeid trematode using Streblosoma toddae as its first intermediate host are both likely to have negative fitness impacts on their hosts. Other trematodes found were at the metacercarial stage and thus use polychaetes as second intermediate hosts. The most common, an opecoelid, infected the polychaetes Heteromastus filiformis and Abarenicola affinis at relatively high abundance. There was no indication of parasite-induced mortality in these two hosts based on the relationship between host size and infection intensity. However, a comparison of intact H. filiformis individuals with those that fragmented during collection revealed a significantly higher number of opecoelid metacercariae per segment in the fragments than in the complete individuals, suggesting that infection may compromise the structural integrity of the polychaetes. These results suggest that there exists a great diversity of both trematodes and host–trematode associations within the polychaete fauna, whose ecological impact remains to be quantified.

Greenland has more than 200 years of history of studies of the sponge fauna and is the type locality for a number of species. Many of these have not been encountered since, and as the type material has been hard to find or even lost, their taxonomic status has remained uncertain. In this study all species of calcareous sponges previously reported from Greenland are reviewed. The revision is based predominantly on new or unidentified material collected during various expeditions, but also on material used by previous authors. This includes samples from all coasts of Greenland, from the southernmost Kap Farvel area to Peary Land on the northern coast, some of the northernmost records of calcareous sponges ever. Greenland is a transition zone between the western and eastern Atlantic boreal calcareous sponge faunas, being home to species from both sides of the North Atlantic combined with some true Arctic species. There is also a strong link between the Canadian and Greenlandic sponge faunas. Twenty-eight species have been identified, from which six are new to Greenland and one is new to science. New records for Greenland are: Clathrina arnesenae (Rapp, 2006); Clathrina camura (Rapp, 2006); Clathrina pellucida (Rapp, 2006); Sycon abyssale Borojevic & Graat-Kleeton, 1965; Leucandra valida Lambe, 1900; and Sycettusa thompsoni (Lambe, 1900). Clathrina tendali sp. nov. has been described from western Greenland and Leucosolenia corallorrhiza (Haeckel, 1872) and Leucandra penicillata (Schmidt, 1869) have been resurrected. Keys for identification of higher taxa and the different species of Greenlandic Calcarea are provided.

The degree of isolation of oceanic islands makes these environments an excellent model for evolutionary studies. Proper knowledge of the species composition of oceanic islands, however, is required to better understand evolutionary processes (e.g. speciation events). A 3-year survey in the shallow waters (up to 30 m) of the Trindade and Martin Vaz oceanic insular complex, and a literature review on the data published for these islands and for Fernando de Noronha and São Pedro and São Paulo oceanic archipelagos have been conducted to document the biodiversity of echinoids and holothuroids from these isolated Brazilian oceanic islands. Sixteen species were collected and characterized morphologically, including two first records for the South Atlantic and one for Brazil. Comparison with conspecific specimens from the Brazilian coast and congeners was also done. Species richness increased from six to 18; the richness in Trindade Island being the highest among the South Atlantic oceanic islands. However, these islands remain undersampled beyond 30-m depth. Endemism was very low, suggesting the potential role of oceanic currents and seamounts as stepping-stones in transoceanic dispersal of species to remote islands. The Brazilian oceanic islands are impoverished oceanic outposts of the Brazilian Province; nevertheless, endemic species and intraspecific morphological variations compared with the mainland suggest they may also be regions of speciation. Documenting their biodiversity is critical for effective management and conservation of their marine ecosystems.

During surveys of rocky shores in Shetland, the Australasian barnacle Elminius modestus was found at 3 out of 42 transect sites and at 6 out of 11 shores searched for its presence. Large populations were present only in Vidlin Voe with a few individuals present at other sites including Lerwick Harbour. These observations extend the northern recorded limit of distribution of E. modestus by approximately 450 km.

The spread of the Australasian barnacle Elminius modestus Darwin along the coasts of the British Isles has been followed with interest by marine biologists since the animal was first found in the region of Portsmouth in 1946. Crisp (1958) describes the spread of Elminius up to 1957 and reviews the factors which are important in encouraging or restricting the spread of the species. On the west coast of Scotland, Elminius is common in the Clyde and a few individuals have been recorded on settling panels in Dunstaffnage Bay near Oban (Barnes & Stone, 1972). On the east coast of Scotland, Elminius is known to be common in the Firth of Forth and a few individuals have been recorded from the Tay Estuary (Jones, 1961). Thus, the previous recorded northern limit of distribution of Elminius modestus lies at about 56° 30′ N. Our brief report describes how Elminius has now been found in the northernmost part of the British Isles.

As a part of the programme designed to monitor the effects of the oil terminal now being built at Sullom Voe on the north-east coast of the Shetland mainland, we have been concerned with the survey of plant and animal populations on rocky shores.

The elimination of unwanted catch in mixed species fisheries is technically challenging given the complexity of fish behaviour within nets. Most approaches to date have employed technologies that modify the nets themselves or use physical sorting grids within the gear. There is currently increasing interest in the use of artificial light to either deter fish from entering the net, or to enhance their escapement from within the net. Here, we evaluated the differences in catch retained in a standard otter trawl, relative to the same gear fitted with a square mesh panel, or a square mesh panel fitted with LEDs. We found that the selectivity of the gear differed depending on water depth. When using a square mesh panel in shallow depths of 29–40 m the unwanted bycatch of whiting and haddock was reduced by 86% and 58% respectively. In deep, darker water (45–95 m), no change in catch was observed in the square-mesh panel treatment, however when LEDs were added to the square-mesh panel, haddock and flatfish catches were reduced by 47% and 25% respectively. These findings demonstrate the potential to improve the performance of bycatch reduction devices through the addition of light devices to enhance selectivity. The results also highlight species-specific and site-specific differences in the performance of bycatch reduction devices, and hence a more adaptive approach to reduce bycatch is probably required to maximize performance.

The systematic position of the giant squid Architeuthis remains unresolved but comparison of beak morphometrics is an approach that has not been attempted before. Additional data for the relationship between mantle length (ML) and lower beak rostral length (LRL) suggest that Architeuthis sp. in the North Atlantic, South Africa and New Zealand are parts of the same asymptotic relationship. Comparison of beak dimensions of Architeuthis from the North Atlantic, South Africa and New Zealand with those of two distinct species of Todarodes, from the Mediterranean and southern Africa, indicate that there may be only one species of Architeuthis in these three regions. No consistent morphological evidence has yet been found to indicate more than one species of Architeuthis in the Atlantic or in the southern hemisphere.

Three sampling surveys were carried out, by SCUBA diving, in the Algarve (southern Portugal) in December 2007. A total of 57 species of gymnolaemate Bryozoa were identified. Of these, eight species were new to science (Mollia cristinae sp. nov., Hippoporina teresae sp. nov., Schizoporella spinosa sp. nov., Fenestrulina inesae sp. nov., Celleporina derungsi sp. nov., Dentiporella saldanhai sp. nov., Rhynchozoon celestinoi sp. nov. and Rhynchozoon rosae sp. nov.). Another 16 species are cited for the first time in Portuguese waters; of these, Stephanollona contracta is cited for the first time in European continental waters. Reference material deposited in several collections was also revised, and lectotypes and paralectotypes were selected for Mollia multijuncta and Dentiporella sardonica, species subjected to diverse interpretations. In addition Rhynchozoon revelatus was found to be a junior synonym of D. sardonica. The species collected in the study area reflect the existence of Lusitanian, Mauretanian and Mediterranean influences; the latter influence is of interest as the Mediterranean species found were previously considered endemic to the Mediterranean Sea and are usually found in shallow waters. Finally, a large degree of intracolonial variability was observed in some of the species studied, especially in Stephanollona armata, which may be taken into account in studies of the geographical variability and differentiation of cryptic species.