The ‘Shinkai Seep Field’ is a serpentinite-hosted chemosynthetic ecosystem in the Southern Mariana Forearc. In June 2015 the site was revisited and a number of rissoiform gastropods were collected. Taxonomic investigations revealed that these specimens represent a hitherto undescribed species of Provanna (Gastropoda: Abyssochrysoidea), described herein as Provanna cingulata n. sp. This new species is characterized by numerous spiral keels, lack of significant axial sculpture, rounded and inflated whorls, and large size for the genus. With the shell height exceeding 16.5 mm (may reach 20 mm), it is the largest Provanna species known thus far. Phylogenetic analysis using 411 bp of the cytochrome oxidase c subunit I (COI) gene confirmed its systematic placement within the genus Provanna. This is the only gastropod from a family endemic to chemosynthetic ecosystems thus far known from the ‘Shinkai Seep Field’. Furthermore, with a collection depth of 5687 m, it represents the deepest known bathymetric range for the superfamily Abyssochrysoidea as a whole.

The shanny/common blenny (Lipophrys pholis) and long-spined scorpionfish/bullhead (Taurulus bubalis) are commonly encountered, sympatric species within much of Great Britain's rocky intertidal zones. Despite being prey items of the cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) respectively, and both contributors to the diet of the near-threatened European otter (Lutra lutra), little is known on the population dynamics of the temperate specimens of Great Britain. It is further less known of the degrees of sympatricity between the two fish species and to what extent they are able to coexist. The current study examines spatio-temporal distributions and abundances at various resolutions: monthly population dynamics of both species along England's Yorkshire coast and seasonal population dynamics along the Yorkshire coast and around the Isle of Anglesey, Wales. Studies of their abundances, sizes, degrees of rock pool co-occurrence and diel activities are further examined, which indicate coexistence is maintained when interspecific co-occurrence takes place only between specimens of similar sizes, thus demoting size-related dominance hierarchies.

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.

pCO2/pH perturbation experiments were carried out under two different pCO2 levels to evaluate effects of CO2-driven ocean acidification on semi-continuous cultures of the marine diatom Skeletonema pseudocostatum CSA48. Under higher pCO2/lowered pH conditions, our results showed that CO2-driven acidification had no significant impact on growth rate, chlorophyll-a, cellular abundance, gross photosynthesis, dark respiration, particulate organic carbon and particulate organic nitrogen between CO2-treatments, suggesting that S. pseudocostatum is adapted to tolerate changes of ~0.5 units of pH under high pCO2 conditions. However, dissolved organic carbon (DOC) concentration and DOC/POC ratio were significantly higher at high pCO2, indicating that a greater partitioning of organic carbon into the DOC pool was stimulated by high CO2/low pH conditions. Total fatty acids (FAs) were significantly higher under low pCO2 conditions. The composition of FAs changed from low to high pCO2, with an increase in the concentration of saturated and a reduction of monounsaturated FAs. Polyunsaturated FAs did not show significant differences between pCO2 treatments. Our results lead to the conclusion that the balance between negative or null effect on S. pseudocostatum ecophysiology upon low pH/high pCO2 conditions constitute an important factor to be considered in order to evaluate the global effect of rising atmospheric CO2 on primary productivity in coastal ocean. We found a significant decrease in total FAs, however no indications were found for a detrimental effect of ocean acidification on the nutritional quality in terms of essential fatty acids.

Herbivorous amphipods of the family Ampithoidae have an important role in marine ecosystems. Ampithoe qeshmensis sp. nov. is a new member of Ampithoidae from the Qeshm Island, Persian Gulf. The new species resembles A. kava, A. katae and A. cookana based on the second male gnathopod. Ampithoe qeshmensis sp. nov. is characterized by round and reduced distoventral spur on uropod 1 in male, mandibular palp article 3 longer than second one, robust seta on palm of second male gnathopod, and longer flagellum than peduncular article 5 on the second antenna.

Examining how variability in population abundance and distribution is allotted among different spatial scales can inform of processes that are likely to generate that variability. Results of studies dealing with scale issues in marine benthic communities suggest that variability is concentrated at small spatial scales (from tens of centimetres to few metres) and that spatial patterns of variation are consistent across ecosystems characterized by contrasting physical and biotic conditions, but this has not been formally tested. Here we quantified the variability in the distribution of intertidal rocky shore communities at a range of spatial scales, from tens of centimetres to thousands of kilometres, both in the NE Atlantic and the Mediterranean, and tested whether the observed patterns differed between the two basins. We focused on canopy-forming macroalgae and associated understorey assemblages in the low intertidal, and on the distribution of Patella limpets at mid intertidal levels. Our results highlight that patterns of spatial variation, at each scale investigated, were consistent between the Atlantic and the Mediterranean, suggesting that similar ecological processes operate in these regions. In contrast with former studies, variability in canopy cover, species richness and limpet abundance was equally distributed among spatial scales, possibly reflecting the fingerprint of multiple processes. Variability in community structure of low intertidal assemblages, instead, peaked at the largest scale, suggesting that oceanographic processes and climatic gradients may be important. We conclude that formal comparisons of variability across scales nested in contrasting systems are needed, before any generalization on patterns and processes can be made.

There is growing concern about the impact of contemporaneous ocean acidification on marine ecosystems, but strong evidence for predicting the consequences is still scant. We have used the gastropod Trophon geversianus as a study model for exploring the importance of oceanographic variables (sea surface temperature, chlorophyll a, oxygen, calcite and pH) on large-scale latitudinal variation in mean shell length and relative shell weight. Data were collected from a survey carried out in 34 sites along ~1600 km. Neither shell length nor relative shell weight showed any monotonic latitudinal trend, and the patterns of spatial variability were rather complex. After correcting for spatial autocorrelation, only pH showed a significant correlation with mean shell length and relative shell weight, but contrary to expectations, the association was negative in both cases. We hypothesize that this could mirror the negative effect of acidification on growth rate, which may cause larger asymptotic size. Latitudinal trends of body size variation are not easy to generalize using ecogeographic rules, and may be the result of a complex interaction of environmental drivers and life-history responses.

The purple sea urchin P. lividus is a marine resource greatly valued for its highly nutritious roe. The objective of this work is to analyse the spatial distribution pattern and population structure of this species in the region of Cantabria (Bay of Biscay) in order to identify the most appropriate zones for sustainable harvesting and for the establishment of adequate management strategies. Two depth ranges were studied (<5 and 5–10 m) in five coastal areas. The available stock of commercial individuals (size >55 mm) was estimated based on the density of individuals and biometric parameters. Significant differences were found among areas but not among depth ranges. Three areas showed low densities with large individuals, whereas two areas showed high densities with small individuals. Despite the average smaller size of the individuals, these high-density areas accumulated 76% of the commercial stock, making these the most suitable zones for the sustainable harvesting of P. lividus in the region. The high variability of the observed density values resulted in elevated uncertainty in the estimation of stocks. However, the high sea urchin densities together with the high percentages of commercial individuals suggest that the resource is currently underexploited. Further studies should be carried out, and precautionary measures should be adopted before opening the fishery. The suitability of many of these measures is discussed in the present work, as a necessary step in the management of the P. lividus fishery in Cantabria.

The distribution and feeding ecology of two puffer fish, Sphoeroides testudineus (Linnaeus, 1758) and Colomesus psittacus (Bloch & Schneider, 1801), were investigated in a tropical estuary (north-eastern Brazil). The hypothesis tested was that these two species partition available resources spatially, and that the effects of interspecific competition can be reduced by changes in the feeding strategy and using alternative resources. This study was carried out between February 2011 and January 2012, on a beach and three tidal creeks of the Mamanguape River estuary. Data on the distribution and relative abundance of the two species were collected using beach seine, with data on temperature, salinity and turbidity also recorded. The diets of the species (S. testudineus N = 399; C. psittacus N = 108) were analysed by the Index of Relative Importance (IRI). Sphoeroides testudineus was found in the entire area, but was particularly abundant in the upper estuary, while C. psittacus was captured exclusively in the upper estuary, with all individuals assumed to be juveniles. In regard to feeding, juvenile S. testudineus predated on Bivalves, Ceratopogonidae larvae, calanoids and gastropods; whilst C. psittacus showed a diet more specialized in Brachyura and Cirripedia. These results suggest that there are differences in both habitat utilization and feeding habits of these two puffer fish species in this estuary.

Chondrichthyans are usually caught incidentally in fisheries for species of high commercial value and then discarded on board or landed as by-products. On the coast of Chubut province and adjacent waters (43°00′S–44°56′S) a bottom trawl fishery has developed targeted at the Patagonian shrimp (Pleoticus muelleri) and common hake (Merluccius hubbsi). Since 2005, this fishery has been monitored by the On-board Observers Program of Chubut province (POBCh). With the aim of advancing towards an ecosystem approach, POBCh not only collects information about target species but also about all the species caught by the trawl nets of the province fisheries. From the information collected by this programme it was possible to identify and record the chondrichthyan species vulnerable to the fishing gear used by the coastal fleet that operates from Puerto Rawson. The composition of the fleet catch was characterized according to the target species during the 2005–2014 period. In the analysis of 3786 hauls, 23 species of chondrichthyans (seven species of sharks, 15 species of batoids and a single species of Holocephali) were identified. Seven species showed a frequency of occurrence greater than 10% (Callorhinchus callorynchus, Discopyge tschudii, Mustelus schmitti, Sympterygia bonapartii, Psammobatis normani, Squalus acanthias and Zearaja chilensis). Species spatial distribution was evaluated and five areas of species assemblages were established. Besides the aspects related to bycatch, these analyses have contributed to the knowledge of the chondrichthyan biodiversity in the provincial coast where the fleet operates, a region with incomplete and mostly dispersed and outdated information.

Shifting prey distributions due to global warming are expected to generate dramatic ecosystem-wide changes in trophic structure within Arctic marine ecosystems. Yet a relatively poor understanding of contemporary Arctic food webs makes it difficult to predict the consequences of such changes for Arctic predators. Doing so requires quantitative approaches that can track contemporary changes in predator diets through time, using accurate, well-defined methods. Here we use fatty acids (FA) to quantify differences in consumer diet using permutational multivariate analysis of variance tests that characterize spatial and temporal changes in consumer FA signatures. Specifically we explore differences in Greenland shark (Somniosus microcephalus) FA to differentiate their potential trophic role between Svalbard, Norway and Cumberland Sound, Canada. Greenland shark FA signatures revealed significant inter-annual differences, probably driven by varying seal and Greenland halibut responses to environmental conditions such as the NAO, bottom temperature, and annual sea-ice extent. Uncommon FA were also found to play an important role in driving spatial and temporal differences in Greenland shark FA profiles. Our statistical approach should facilitate quantification of changing consumer diets across a range of marine ecosystems.

Sponges interact in various ways with a wide variety of organisms in benthic communities and ecological interactions may influence the distribution, abundance and diversity of these organisms in different sites. Although several studies have already been developed for Demospongiae, knowledge of ecological interactions in the class Calcarea is lacking. Some calcareous sponges are considered weak competitors for space and to have developed strategies to survive in highly dynamic environments, such as exploitation of micro refuges and epibiosis. We aimed to investigate the influence of intra- and interspecific interactions in the abundance, growth and lifespan of the calcareous sponge Clathrina aurea in south-eastern Brazil. Two peaks of abundance and area coverage were observed during the studied year, probably associated with reproductive effort. We found no evidence of intra- or interspecific competition between the sponge and the benthic community. Clathrina aurea was found using parts of other organisms as substrate (epibiosis), such as algae, demosponges and corals. It was seen that the interaction of the sponge with coral polyps positively affects the lifespan of sponge individuals and the interstices of corals probably promote a micro refuge for C. aurea against competitors for space and predators.

The rocky intertidal communities of Ireland contain a mix of cold- and warm-adapted species, however the spatial distribution of these communities has not been investigated in a systematic way. Based on a benthic community dataset collected in 2003 at 63 sites, several statistical analyses were combined with the aims of (i) detecting groups of similar communities and their spatial arrangement, (ii) relating these groups to environmental factors and (iii) identifying the species that drive the different community groups. Sørensen's index suggested two marine community groups, one of the east and south-east (termed ‘east’) and the other in the west, south-west and north (termed ‘west’). A second partition based on combined wave exposure and sea surface chlorophyll comprised four groups, as did a further partition based on combined sea surface and air temperatures. The spatial arrangement of wave height plus chlorophyll conditions agreed reasonably well with the binary marine community partition, but the temperature partition did not. The ‘east’ community appeared to be associated with low wave height and chlorophyll conditions. The species that were most influential to the ‘east’ community were Balanus crenatus, Austrominius modestus and Fucus vesiculosus. The ‘west’ sites were associated with high wave height/low chlorophyll (with some variation in this due to local shelter) and the species Paracentrotus lividus, Chthamalus stellatus, Alaria esculenta and Himanthalia elongata. A longitudinal pattern rather than one associated with latitude was evident in this marine community and local drivers rather than temperature clines appeared most important for the dominant community patterns.

Life history accounts for the chance of survival and reproductive success of a species, considering, for example, when, how often and how much a species reproduces. Consequently, it is directly related to the success or failure of bioinvasions. Here, we investigated some aspects of the life history of the cryptogenic calcareous sponge Sycettusa hastifera. A population from Arraial do Cabo, Brazil (south-western Atlantic) was investigated from September 2008 to December 2009 by monthly collections and histological analyses. We observed that S. hastifera reproduced continuously throughout the year without seasonality and presented high fecundity. The fecundity was not different depending on the sponge body part (top or base), but it was related to the wet weight of the sponge (although a minimum size was not required for reproduction). Reproduction could not be predicted by the seawater temperature. The reproductive characteristics of S. hastifera were similar to those of other previously studied calcareous sponges. Sycettusa hastifera shows traits of an invasive species, such as high fecundity, short life cycle, early sexual maturity and the ability to use pioneer habitats. Consequently, it possesses several characteristics that would allow it to invade new areas.

Quantifying exchange of particulate matter between coastal and open waters is an important and often unresolved issue. Here, we apply phytoplankton order richness as an innovative marine tracer to identify the geographic position of a coastal exchange zone in the SE North Sea, including its variability in time and space. Previous observations on dynamics of suspended particulate matter accumulation resulted in a hypothesized boundary between coastal waters (including the Wadden Sea) and open North Sea waters, the so-called ‘line-of-no-return’. Our study along two transects (Terschelling, Noordwijk) in the Dutch coastal zone showed seasonality patterns in phytoplankton order richness, both for diatoms and flagellates. The coastal Wadden Sea was found to be clearly different from the open North Sea, implying that seasonality in Wadden Sea phytoplankton is at least partly driven by local environmental conditions. Seasonality in flagellates was found to be more uniform than seasonality in diatoms. Stations in the coastal North Sea to a distance of 10 km (Terschelling) to 20 km (Noordwijk) from the shore appeared to be at the inside of the ‘line-of-no-return’. Our findings indicate that this approach is a useful aid in exploring mixing of particulate matter between coastal and open waters and to study the responses of phytoplankton communities to environmental drivers.

This study characterizes the abundance and spatial distribution of siphonophores between the Trinidad Channel (50°06′S) and the Strait of Magellan (52°45′S) in southern Chile, during October–November 2009. Ten species were identified, of which Agalma elegans, Rosacea plicata and Sphaeronectes fragilis are new records for this region. Dominant species showed similar dominance values e.g. Lensia conoidea (26.3%), Dimophyes arctica (24.6%), Lensia meteori (22.2%) and Muggiaea atlantica (20.7%). Eudoxids of L. conoidea and D. arctica represented 97.3% of all eudoxids collected and they were mainly collected in estuarine waters. The highest densities were found in estuarine waters (high vertical stratification and low temperature, salinity and dissolved oxygen values). On the other hand, the lowest densities were found in coastal areas influenced by permanent influx of Sub-Antarctic waters from the Pacific (greater instability and vertical mixing, higher temperatures, salinity and dissolved oxygen values). Temperature and dissolved oxygen were the most important environmental variables. In general, all the dominant species showed a positive association with temperature and a negative association with dissolved oxygen (with the exception of L. meteori). The vertical distribution showed that M. atlantica was mainly distributed in the first 50 m, in association with estuarine waters, while L. conoidea, L. meteori and D. arctica were mainly found in the deeper layer (50–200 m) and in association with modified Sub-Antarctic waters. The comparison of the results obtained in the springs of 1996 and 2009 showed a significant increase in abundance.

Molluscs are subjected to intense harvesting in many areas around the world. Conservation measures have been developed to preserve populations of an overexploited gastropod species, the abalone Haliotis tuberculata coccinea. This species was surveyed in subtidal localities throughout coastal Tenerife, Canary Islands over the last two decades (1994–2014). A clear indicator of non-recovery was observed in the decrease of mean size throughout the last two decades, even after the inclusion of this species in the Regional Catalogue of Endangered Species. The mean size of abalones decreased from 33.5 mm (1994) to 28–29 mm (2002 and 2014), corresponding to sub-adult individuals. The structure of size classes was typical of an overexploited species, with reduced occurrence of large individuals (>50 mm). Several factors might explain this pattern such as illegal harvesting, proliferation of featureless benthos and a decrease of suitable habitats for colonization and settlement. Complementary conservation actions are urgently needed to preserve this species in the area studied.