Spatial variation in the structure of macrobenthic assemblages on intertidalflats is known to be related to different environmental variables. Most ofthe studies have observed that along the estuarine gradient, salinity is themost important variable driving the patterns of the macrobenthicassemblages. However, the great majority of studies have been done on singleestuarine systems in temperate regions. We investigated the relationshipbetween the macrobenthic assemblages in intertidal habitats and theenvironmental variables along three tropical estuaries. From lower to upperestuarine regions we sampled benthic macrofauna, salinity and sediments. Thestructure of the benthic assemblages was primarily related to salinity.There was a decrease in the number of taxa from the upper to the lowerestuarine regions, indicating important deviation from Remane's model ofestuarine diversity. There were important similarities of taxa abundancealong different estuarine salinity gradients which can be properly tested inother tropical and temperate regions. We advocate that in order to adoptgeneral and robust management practices it is essential to identify broadpatterns and general rules governing estuarine systems.

Understanding the role played by sunken vessels in Mediterranean marineecosystems is acquiring increasing importance. The aim of this research wasto study the fish communities associated with four shipwrecks, by means ofunderwater visual censuses performed by a remotely operated vehicle, and totest the differences in composition of fish assemblages between theseshipwrecks and the adjacent soft bottoms, considered as control sites.Multivariate analysis on the total fish assemblage showed significantdifferences between wrecks and controls. Results also showed higher levelsof species richness and abundance near all wrecks than at a short distancefrom them on soft bottoms, thus indicating that these sunken vessels, thanksto their higher habitat complexity, act as artificial reefs, attractingaggregations of fish species and leading to a greater diversification of thelocal fish assemblage. Nevertheless, shipwrecks, which are an ideal targetfor recreational fishermen, could contribute to the over-exploitation ofsome high-value fish species, such as Mycteroperca rubra, Dentex dentex and Diplodus spp., attracted by theartificial hard substrate of the vessel-reefs. The recent Europeandirectives suggest an urgent need for a better understanding of the crucialrole played by these potential sources of pollutants on marine environmentsand ecosystems. An ecosystem approach to study and monitor these pollutantsources is, therefore, mandatory for appropriate remediation and/ormitigation of the potential negative effects on a productive and healthyocean.

In many coastal areas substrate is the limiting resource for benthicorganisms. Some sessile species can be used as secondary substrate, reducingcompetition and increasing coexistence. In southern Chile, annualpopulations of Macrocystis pyrifera recruit and grow on theshells of Crepipatella fecunda. This study describesecological interactions between the kelp and the slipper limpet over anannual cycle. The degree of kelp overgrowth was established by collectingsporophytes and through in situ submarine photography overa 10 month period (starting when kelp recruits became visible and endingwhen sporophytes were no longer present). Changes in the biochemicalcomposition of the limpet tissue were also recorded by chemical analyses, toevaluate the potential effects (positive/neutral/negative) of kelp on C. fecunda nutritional condition. The results indicatethat both species coexist, although kelp overgrowth may cause a decrease incarbohydrates in C. fecunda tissues, restricted to theperiod when the kelp forest reaches its maximum biomass. Individually, theshort duration of the maximum overgrowth period and the size reached by C. fecunda females (up to 65 mm shell length) may enablerapid limpet recovery, avoiding competitive exclusion. On a populationlevel, the M. pyrifera annual cycle generates the needed‘break’ for C. fecunda populations, reducing the effects ofkelp overgrowth. Thus, in the view of the neutral effect of kelp overgrowth,together with the positive effect of C. fecunda on M. pyrifera recruitment described somewhere else, thisecological interaction can be categorized as commensalism.

The phytoplankton community structure and abundance in the south-easternBlack Sea was measured from February to December 2009 using and comparinghigh performance liquid chromatography pigment and microscopy analyses. Thephytoplankton community was characterized by diatoms, dinoflagellates andcoccolithophores, as revealed by both techniques. Fucoxanthin,diadinoxanthin, peridinin and 19′-hexanoyloxyfucoxanthin were the mainaccessory pigments showing significant correlation with diatom-C r2 = 0.56–0.71, P < 0.05), diatom-C (r2 = 0.85–0.91, P < 0.001), dinoflagellate-C (r2 = 0.39–0.88, P < 0.05) andcoccolithophore-C (r2 = 0.80–0.71, P < 0.05), respectively.Microscopy counts indicated a total of 89 species, 71% of which weredinoflagellates, 23% were diatoms and 6% other species (mainlycoccolithophores). Pigment-CHEMTAX analysis also indicated the presence ofpico- and nanoplankton. Phytoplankton carbon (phyto-C) concentrations werehighest in the upper water column, whereas chlorophyll-a (Chl-a) showed a deep maximum. Average phyto-C was higher at thecoastal station (291 ± 66 µg l−1) than at the offshore station (258 ± 35 µg l−1), not statistically different (P > 0.05). The coastal station also had higher Chl-a concentrations (0.52–3.83 µg l−1)compared to the offshore station (0.63–2.55 µg l−1), notsignificant (P > 0.05). Our results are consistent withother studies and indicate that the southern Black Sea is shifting towardsmesotrophy with the increasing prevalence of dinoflagellates compared todiatoms.

Temporal variations in the taxonomic relatedness of periphytic ciliatemicrofauna during colonization periods were studied in coastal waters of theYellow Sea, northern China, from May to June 2010. Samples were collected attwo depths of 1 and 3 m, using glass slides as artificial substrates. Thecolonization dynamics of ciliate microfauna on the slides revealed similarpatterns in species composition at both depths. In the immature communities(1–7 days), the taxonomic patterns showed high variability compared to thosein the mature ones (10 days and more). However, taxonomic relatednessparameters at the two depths differed during early stages of colonization(e.g. 1–3 days). Taxonomic diversity (Δ) was subject to high variability(coefficients of variation >10%) in both immature and mature communities,whereas taxonomic distinctness (Δ*), average taxonomic distinctness (Δ+) and variation in taxonomic distinctness (Λ+)showed high stability (coefficients of variation <10%) during thecolonization times of 3–21 days. These findings suggest that 3–21-dayexposure times are sufficient to detect the taxonomic distinctness ofperiphytic ciliate microfauna at water depths of 1–3 m for the purposes ofecological research and monitoring of marine ecosystems.

Clownfish and their associated sea anemones are icons of tropical andsubtropical coastal ecosystems, but bleaching and collecting for theaquarium trade has reduced their population densities in severalIndo-Pacific locations. We surveyed four Entacmaea quadricolor populations and their associated clownfish Amphiprion clarkii in Hong Kong. These assemblagesrepresented a combination of exposed and sheltered, flat bottomed and slopedconditions. Different from tropical areas, where E. quadricolor is usually found in sheltered shallow waters, thefour populations in Hong Kong were distributed in 4–10 m depths, beingdensest on a 40 × 80 m slope of volcanic rocks (34.2–76.6% substrate coverand 48.7–102.1 ind  m−2) at an exposed site. This distributionpattern could be explained by the high turbidities associated with riverdischarge and sedimentation rates in local waters, which discourage theestablishment of E. quadricolor populations in sheltered bays; shallowhabitats might not be suitable for E. quadricolor in HongKong due to strong wave actions generated by typhoons. Amphiprion clarkii was present at low densities (0.07–0.26 fish m−2) across the sites. Our data provide abaseline for monitoring the changes of these conspicuous members of shallowwater communities in Hong Kong.

The shallow water sea anemone Phymanthus crucifer exhibitsthree distinct morphotypes, characterized by the presence or absence ofprotuberances on the marginal tentacles, as well as intermediate forms. Thetaxonomic status of the different morphotypes and the diagnostic value ofprotuberances on the tentacles have been debated for this species and thefamily Phymanthidae. We analysed the external and internal anatomy, cnidaeand three mitochondrial molecular markers for representatives of each of thethree morphotypes. In addition, we address the putative monophyly of thefamily Phymanthidae based on molecular data. With the exception of theprotuberances, our morphological and molecular results show no differencesamong the three morphotypes; thus, we consider this feature to beintraspecific variability within P. crucifer. Furthermore,molecular data reveal that the family Phymanthidae is not monophyletic. Inaddition, we discuss several diagnostic morphological features of the familyPhymanthidae.

Community structure, species composition, and changes over time afterdisturbances are frequently studied using common descriptors. We used rankabundance distribution plots (RADs), Rényi entropy plots, common theoreticalcommunity models, ordination analysis of similarities (ANOSIM and Clusters),and abundance spectra analyses to study the effects of a gradual naturalpopulation decline and an anthropogenic punctuated disturbance on thestructure of octocoral communities in Panama, considered a hot spot area foroctocoral diversity in the Tropical Eastern Pacific. Over a 17-month period,no significant change was found in community structure after a naturalyearly population decline of 25.2%. After a disturbance, however, differentrecovery trajectories were observed in various coral communities. Possiblephysical and biological explanations for the observed differences includeinitial local species diversity and abundance, species life historypatterns, colony morphology, and the geographical location of the community.Differences in community structure between study sites were best describedusing a combination of community descriptors, RADs, and abundance spectra.Rényi plots were useful in identifying changes in community structure,whereas the extent of the changes was best evaluated using ANOSIM andcluster analysis.

A new species, Poecilochaetus anterospinus sp. nov., isdescribed from the east and south shores of Oahu, Hawaii. Poecilochaetus anterospinus sp. nov. is unique in thegenus by the presence of noto- and neuropodial spines from chaetiger 11 toposterior segments. Neuropodial spines on anterior chaetigers are absent inall other Poecilochaetus species while notopodial spinesare limited to segments preceding the pygidium. Poecilochaetus cf. koshikiensis,originally described from Japan, is newly recorded from Hawaii andapparently widely distributed in the western Pacific and South-east AsianSeas. Poecilochaetus sp. is distinguished from the othertwo species by the distribution of the ampullaceous cirri (7–12) and itschaetal characters.

Patagonema iubatum gen. nov. sp. nov. is described from asandy beach at Playa Pozo, Golfo Nuevo, Argentina. It resemblesOncholaimidae (Nematoda: Enoplida) and it is characterized by a buccalcavity comprising a combination of three teeth and three mandibular ridgeswith small teeth. The new genus is also characterized by the presence ofpapillose pre-cloacal supplements, cephalated spicula and a gubernaculumwith dorsal apophysis and lateral piece, and a new demanian systemconfiguration. Patagonema iubatum sp. nov. has 9–11papillae-like pre-cloacal supplements, short and cephalated spicula and agubernaculum with dorsal apophysis and pointed lateral piece. Its positioninside Oncholaimidae is discussed.

The Mediterranean Sea is currently under siege by a conspicuous alienpressure, and, within some families (e.g. the Ostreidae), the number ofnative species seems to be remarkably outnumbered by that of the alien ones.We wanted to test the reliability of the molecular data currently availableon the small alien oysters recently invading the Mediterranean Sea. Samplesfrom Greece and Turkey, encompassing the known species-specificmorphological variation, were sequenced for the markers with the widesttaxonomic coverage in the group of small oysters (i.e. the 16S rDNA and theCOI). The sequences obtained have been compared with those available inGenBank, and a possible identification at the species level has been finallytested in a DNA-barcoding fashion. The present results clearly demonstratedthat our samples belong to a single, morphologically highly variablespecies. Their 16S sequences were closely related to a sequence registeredunder the name Dendostrea folium, with a genetic distancewhich does not warrant conspecificity. Additionally, a remarkable number ofsequences retrieved from the GenBank (of both genes) did not form amonophyletic group according to the published classification of thevouchers, suggesting—at least in part—an origin from specimens not properlyidentified. Both genes seem promising for use as DNA-barcode, although theCOI will probably prove more effective. Therefore, we urge the availabilityof a baseline of oyster pedigreed DNA barcode sequences in the publicdatabases, to allow the use of such genetic data to reliably monitorbio-invasions in the Mediterranean Sea.

The veined rapa whelk is one of the most important invasive species in theBlack Sea ecosystem since the 1940s. Following its introduction to the BlackSea, it destroyed most of the bivalve populations, mainly the Mediterraneanmussel and oysters. However, the veined rapa whelk has commercial importancefor the Black Sea fisheries as an alternative product. In this study, weaimed to determine some population parameters of the veined rapa whelk basedon indirect ageing through length–frequency data by using the Bhattacharyamethod. We collected 1704 specimens by dredging along the coasts of SamsunProvince in the Central Black Sea in 2011 from June to November. The age ofthe population varied from 0 to 6. Von Bertalanffy growth parameters wereestimated as L ∞ = 112.35 mm, k = 0.310, t 0 = −0.486 and W ∞ = 243.94 g. Mean length and weight, length–weight relationship,mortality and exploitation rates were derived asL = 56.80 ± 0.36 mm, W = 45.67 ± 0.89 g, W = 0.0006 L2.719, Z = 0.96, M = 0.57, F = 0.39 and E = 0.40, respectively.

T-bar anchor tags and Petersen discs were used during a preliminary mark–recapture experiment in the wild on 268 Octopus vulgaris. Discs, despite causing some injuries, were characterized by a quicker healing (within 5 days) and a higher retention rate than T-bar tags (about 97% versus 22%, respectively), therefore they were considered the best technique for tagging the animals in the subsequent growth studies. From 2010 to 2013, a total of 1604 O. vulgaris (74.4% with a total weight <300 g) were tagged with discs and released in an area of the central western Sardinian Sea (western Mediterranean Sea). Ninety-one specimens were recaptured after 4–63 days of freedom, 59 of which (31 males and 28 females) showed positive growth increments after a minimum time of 8 days at liberty. In general, a high individual variability (0.96–9.09 g day−1) and higher mean daily growth rates in females (3.07–3.65 g day−1) than in males (2.08–2.98 g day−1) were recorded, but this difference was not statistically significant. Using tag–recapture data, the first exponential growth curves for both sexes of Octopus vulgaris of small–medium size from the Mediterranean Sea were obtained, and compared with those available in the literature for the species.

The increasing market demand for Glyptocidaris crenularisshapes its great potential for aquaculture. Temperature is an importantfactor affecting gonad production and quality of sea urchins. Therefore, itis essential and valuable to carry out an evaluation of the temperatureeffects on gonad production and quality in G. crenularisbefore potential aquaculture. Here, we investigated the long-term effects oftemperature on gonad production, colour and flavour in G. crenularis. There was no significant difference of testdiameter, height and body weight between the sea urchins in high (16–23°C)and low (12–16°C) temperatures (P > 0.05). Glyptocidaris crenularis showed significantly highergonad production and index in high temperature and in low temperature (P < 0.05). L*, a*, b* readings were slightly higher in the low temperaturegroups, although no significant difference was found(P > 0.05). Subjective colour and flavour ratings foundthat G. crenularis in the low temperature group showedsignificantly better colour (P = 0.003) and flavour (P < 0.001) than those in the high temperature group.The present study provides valuable and insightful information into theestablishing G. crenularis aquaculture.

The sea urchin Diadema africanum is considered a keyherbivore in sublittoral ecosystems of the Canary Islands. Spatial andtemporal variability in population structure was carried out at GranCanaria. We performed a morphometric and population density analysis during2005, 2006 and 2007 at four sites in zones of Gran Canaria. The studyconsidered a vertical gradient (5, 10 and 20 m depth) during both seasons,the cold season (February and March) and the warm season (October andNovember). The sea urchin D. africanum in Gran Canariaexhibited an overall density of 7.59 ± 2.92 urchin m−2. A two-wayANOVA evidenced spatial differences in mean abundance of the species, whileseasonality was not relevant. The vertical analysis of the abundance of D. africanum showed differences, the smaller sizesappeared at greater depths. The Aristotle's lantern width decreased in avertical gradient, being remarkable between 10 and 20 m. Findings ofuniformity in size over time, a stable range of high densities and the lackof a relationship between the size of the sea urchins and the season revealsthat the density–size strategy displayed by D. africanumwhich explains in turns the high stability of the urchin barrens, which,once developed, remain as areas of permanent desertification in subtidaldepths throughout the Canary Archipelago.

Manta ray (Manta birostris) is the largest ray species, butlittle information is available regarding its biology, distribution andmigratory pattern. During an aerial survey conducted in French Guiana waters(South America) in 2006, the observation of several dozen individuals allswimming in the same direction prompted us to develop a research programmeon this species as part of an environmental impact assessment for oildrilling. Overall, 117 aerial surveys were performed over 3 years in orderto complete a database for this species. In 54 of these flights, a total of138 individuals were observed. A phenological analysis of this species inFrench Guiana waters shows a peak presence between July and December, whichcorrelates with sea surface temperature and net primary production in theocean. The primary production in French Guiana waters is particularly activeduring this period and could explain the annual pattern for thisfilter-feeding animal.

We examined the distribution, hatch-date, growth, and mortality of larval Benthosema pterotum, a dominant pseudoceanic myctophidin the shelf region of the East China Sea, during early autumn when the mainspawning has been predicted. This species is a key species in the food webof this area. Larvae were abundant in the area south of Cheju Island(60–80 m depth), corresponding with the adult habitat. Occurrence of thelarvae was restricted to the onshore side of the shelf-break salinity front,indicating that this front acted as a barrier restricting the offshoredispersion of the larvae. In the area where the larvae occurred, a cycloniceddy is formed, which is considered to limit the dispersal of the larvae,enabling them to recruit into the area of adult habitat. Modes of hatch-dateappeared from late August to early September and from mid to late September,suggesting that large-scale spawning events occurred at least twice duringthe spawning season. Since the modes coincided with the new moon period, B. pterotum is suggested to spawn periodically once amonth around the new moon, resulting in efficient mating and fertilization.Mean absolute growth rate (0.26 mm d−1) and weight-specificgrowth rate (18.8% of dry body weight d−1) were higher thanpreviously reported values of other subtropical–tropical myctophids, whichwould be related to the high food availability in the study area. Dailyinstantaneous mortality coefficient during the first two weeks afterhatching was estimated to be 0.28 d−1 (equivalent to 24.7% mortality d−1).

The feeding biology of bahia sprat (Rhinosardiniabahiensis) was studied in two habitats of a tropical semi-aridestuary, on the north-eastern Brazilian coast. Samplings were collected on amonthly basis (January 2010–February 2011), and fish were caught during theday using an 8 m beach seine. Habitat use was size-dependent, with tidalmudflat occupied by higher size-classes than tidal creeks, which wereoccupied by smaller conspecifics. The diet analysis of differentsize-classes revealed that all sizes of fish consumed similar taxa(Calanoida, Cyclopoida and Decapoda larvae), and that the relativeproportion of taxa consumed reflected fish size. Dietary differences betweenthe two nursery areas mainly reflected prey availability. Although high dietoverlap was only found between some size-classes in tidal mudflat, theseresults seem to demonstrate a strategy for efficient use of space potential;intraspecific competition was probably minimized by a differential habitatuse patterns.

Otolith microstructure analysis was used to determine daily age, growth rateand hatching periods of young of the year (YOY) common two-banded seabream,Diplodus vulgaris, collected at two sites by using beachseine from Çanakkale shallow waters between January and December 2007. Totallength of the YOY D. vulgaris was between 12 and 86 mm andthe daily ages ranged between 42 and 313 days. Somatic growth rate estimatedby fitting a linear regression to the age–length data set was calculated as 0.273 mm day−1. According to the length–age regressionanalysis, maximum daily growth rates were found 0.277 mm day−1 inthe lowest sea temperature period and minimum values of 0.274 mm day−1 were observed in the declining sea temperatureperiod. Analysis of covariance indicated that there were no significantdifferences in the linear growth equations for the two cohorts (F = 0.4008, P = 0.527). Hatching period of the YOY was estimated tooccur between October and March with relatively higher frequency in January.This study has shown that YOY D. vulgaris is a winterspawner in the Çanakkale shallow waters.