A revision of the check-list of the red (Rhodophyta), green (Chlorophyta) and brown (Ochrophyta, Phaeophyceae) seaweeds of Britain has been compiled and revealed 644 taxa, mostly at species level but including infraspecific taxa: 348 reds, 110 greens and 186 browns. There were 30 additions to the list, notably five newly described species and five new non-native additions. In addition to the check-list, an updated list of non-native species was compiled based on a stringent review of the available evidence. We have listed 31 non-native species (~5% of the flora), although the numbers may be considerably higher and probably include species that are effectively naturalized and perceived to be part of the indigenous flora. The check-list is discussed in relation to the impact of molecular techniques on the identification, taxonomy and phylogeny of species, and points to the need for a comprehensive, in-depth study on the identity and relationships of the seaweeds of Britain.

We studied the communities of the invasive Balanus improvisus and native Cerastoderma glaucum populations in the south-western Caspian Sea. The massive movement of live Bivalvia attached to Cirripedia colonies along the studied coastline strengthens the hypotheses asserting the possible negative effects of exotic species on endemic species. Different live stages of both animals including meroplankton and macro-invertebrates were considered in the analysis. Bivalvia larvae showed a downward trend in population, in contrast with an upward trend of Cirripedia larvae from 1996 to 2013. The abundance of C. glaucum decreased west to east along the sea shore in contrast with increasing biomass of B. improvisus. Both Bivalvia and Cirripedia larvae did not show any overlapping temporal abundance. The Cirripedia larvae showed its highest abundance in winter while the bloom of Bivalvia larvae occurred in April and May during 2004–2013. The biomass of B. improvisus reported in this study was higher than those reported for the northern parts and for the middle parts. Distribution patterns of both species were described based on temperature, salinity gradient and local nutrient content. A non-linear growth model of Bivalvia showed the short-term effects of Cirripedia on Bivalvia growth. The controversy between the effects of Cirripedia on the movement of two different Cardiidae (C. glaucum, which is affected by the presence of B. improvisus, and Adacna vitrea with no attached Cirripedia) highlights the contributing role of several other factors including ecosystem degradation.

We studied the effects of four non-nutrient environmental factors (temperature, salinity, irradiance and pH) on the growth inhibition of the macroalgae Ulva pertusa (Chlorophyta) upon the microalgae Heterosigma akashiwo (Rhaphidophyta). Experiments were conducted in single-factor incubation and various two-factor combination experiments in which temperature (10, 15, 25 and 30°C), salinity (10, 20, 30 and 40 g kg−1 water), irradiance (20, 100, 200 and 400 μmol m−2 s−1), and pH (5.5, 7, 8.5 and 10) were varied systematically. The growth rates of U. pertusa and H. akashiwo and the rate of microalgal growth inhibition were altered significantly by changing some of the non-nutrient factors in both the single-factor and the two-factor experiments. The optimal growth conditions for U. pertusa were 20–25°C, salinity of 30 g kg−1, irradiance level of 200–400 μmol m−2 s−1, and pH 8.5–10; optimal conditions for H. akashiwo growth were 25°C, 30 g kg−1, 100 μmol m−2 s−1 and pH 8.5, respectively. The growth inhibitory influence of U. pertusa on H. akashiwo was strongest at 25°C with low salinity (10 g kg−1), high irradiance (400 μmol m−2 s−1) and high alkalinity (pH = 10). The results of this study may be helpful in the development of methods for using green macroalgae to control the proliferation of microalgae in harmful algal blooms (HABs). In particular, these findings provide guidance regarding optimum levels of non-nutrient environmental factors in confined areas, such as aquaculture factories.

This study describes for the first time the reproductive traits of the warm-water pompano, Trachinotus ovatus. Specimens were sampled from landings by artisanal fishing vessels in the NW Mediterranean. Monthly collections, from July 2010 through to September 2012, yielded 226 individuals (118 females and 108 males). The size at 50% maturity (L50) was estimated at 30.9 and 29.1 cm TL for females and males, respectively. Specific reproductive traits, such as oocyte size-frequency distributions, presence of recent post-ovulatory follicles along with oocytes in the final phases of gonadal development, and massive atresia in post-spawning individuals, indicated that pompanos are multiple batch spawners with asynchronous oocyte development and indeterminate fecundity. Monthly variations in the gonadosomatic index and in the phases of gonadal development indicated July and August as the spawning season. There were also noticeable inter-annual variations in spawning phenology, mean diameters of the oocytes, relative batch fecundity and eggs quality, all of which corresponded to changes in sea surface temperatures. This study enhances our understanding of the need for research into the reproduction of warm-water species, which are currently expanding into the increasingly warmer waters of the world's more northerly seas and oceans.

The carapace and chelipeds ornamentation of the deep-water spider crab Rochinia umbonata (Stimpson, 1871), from the Western Atlantic undergo very dramatic ontogenetic changes. Since the also deep-water spider crab Rochinia confusa Tavares, 1991 is differentiated from R. umbonata mostly on the basis of these characters, R. confusa is regarded herein as an ontogenetic stage and, therefore, a junior subjective synonym of R. umbonata.

Sponges of the Mycale genus are an important source of several bioactive metabolites. The raw materials for studies on this genus mainly come from the wild populations. However, the scarce biomass of sponges in the wild has become an obstacle to the better investigation of the active substances. To establish aquaculture methods based on the sexual reproduction of the demosponge Mycale phyllophila and solve the sponge shortage problems, the sexual reproductive cycle of this species was studied. Our investigation is the first to report the sexual reproduction of the Mycale species in the coastal waters of China. We collected the sponge specimens from Dongshan Bay (Fujian, China) monthly from June 2012 to January 2014. Small samples of approximately 8 cm3 in volume were cut from 15 sponges (10 tagged individuals and five random individuals) with surgical scissors for histological analysis. The results indicated that M. phyllophila is a hermaphroditic and viviparous species. The primary oocytes measured 30–50 μm in diameter, while mature oocytes reached 300–400 µm by engulfing nearby nurse cells. Spermatic cysts containing asynchronous cells were found throughout the mesohyl, especially adjacent to the oscula. Macromeres in the middle and micromeres in the periphery were observed as the cleavage progressed. The reproductive activity of M. phyllophila lasted for 5–6 months and peaked when the average water temperature was above 25°C. This suggests that water temperature is an important environmental factor influencing the sexual reproduction cycle.

In this research, the feeding guild composition of the polychaete community was described and analysed in the northern Yellow Sea, China. The polychaete feeding guilds also showed a distinct seasonal abundance fluctuation that was similar to that observed for macrofauna. Burrowers were the most predominant feeding guild, whereas filter feeders and herbivores only constituted a negligible proportion of the total abundance. A Spearman rank correlation was performed to analyse the relationships between the feeding guilds and the environmental parameters. Surface deposit feeders and carnivores appeared to be vulnerable to variations of environmental conditions. However, burrowers and filter feeders were not susceptible to the natural or anthropogenic disturbances, with grain size determined to be the only conclusive factor. These results revealed that the feeding guild of polychaetes showed significant spatial and temporal changes, and spatial heterogeneity was a stronger predictor than temporal variation. The feeding guilds of polychaetes can be applied alone to discern the environmental change, which would be faster and more cost-effective with best equilibrium between the precision of the results and a decrease in taxonomic effort. Furthermore, bimonthly sampling was proved to be unessential and reduction of the sampling frequency was necessary to save expense and effort.

The study of the feeding habits of elasmobranch populations should help to elucidate the ecological role of these fishes in the marine ecosystem. Feeding habits of the apron ray, Discopyge tschudii from San Jorge Gulf were investigated. An evaluation of whether the diet of D. tschudii changes with body size, seasons, maturity stage and sex was performed using a multiple-hypothesis modelling approach. Discopyge tschudii preyed mainly on polychaetes. The consumption of polychaetes was higher in males. Also, amphipods and siphons of clams were preyed more heavily in the cold season and Munida gregaria in the warm season. Stomatopods were consumed more with increasing body size. All prey categories were independent of maturity stage. We concluded that D. tschudii is a benthic feeder.

Aglajidae is a family of tropical and temperate marine Cephalaspidea gastropod slugs regarded as active predators. In order to better understand their food habits and trophic interactions, we have studied the diet of all genera through the examination of gut contents. Specimens were dissected for the digestive tract and gut contents were removed and identified by optical and scanning electron microscopy. Our results confirmed that carnivory is the only feeding mode in aglajids and showed a sharp preference for vagile prey (94% of food items). We suggest that the interaction between crawling speed, presence of sensorial structures capable of detecting chemical signals from prey, and unique features of the digestive system (e.g. lack of radula, eversion of the buccal bulb, thickening of gizzard walls) led aglajid slugs to occupy a unique trophic niche among cephalaspideans, supporting the hypothesis that dietary specialization played a major role in the adaptive radiation of Cephalaspidea gastropods.

As an inherent function of a community, body-size spectrum has been increasingly used as a useful indicator in global ecological research. The colonization dynamics of biofilm-dwelling protozoa with regard to body-size spectrum were studied based on a 1-month baseline survey in coastal waters of the Yellow Sea, northern China. Samples were collected at time intervals of 1, 3, 7, 10, 14, 21 and 28 days from depths of 1 and 3 m. A total of seven body-size ranks were identified based on a trait hierarchy. The individual abundance of the protozoa at each body-size rank was well fitted to the logistic model equation. The body-size spectra showed a clear shift in probability density during the colonization period at both depths. The multivariate approach demonstrated that the temporal dynamics in body-size spectra of the protozoa may be divided into initial (1 day), transitional (3–7 days) and stable (10–28 days) stages during the colonization period. These results provide useful information for ecological research and monitoring programmes using biofilm-dwelling protozoa in marine ecosystems.

The temporal variation in the taxonomic distinctness of biofilm-associated diatom microflora within the colonization process was studied in coastal waters of the Yellow Sea, northern China from May to June 2014. Samples were collected at depths of 1 and 3 m, using glass slides as an artificial substratum. The colonization dynamics of diatom microflora showed similar species composition at both depths. In the young communities (1–7 days), the taxonomic patterns showed high variability compared with those in the mature ones (10 days and more). However, taxonomic distinctness indices at the two depths differed during early stages (e.g. 1–3 days). The taxonomic diversity (Δ) represented a high variability (coefficients of variation >10%) over all colonization periods, whereas the taxonomic distinctness (Δ*), average taxonomic distinctness (Δ+) and variation in taxonomic distinctness (Λ+) showed high stability (coefficients of variation <10%) after 7 days. Based on these findings, we suggest that the exposure time of more than 7 days may be sufficient to identify the taxonomic distinctness of biofilm-associated diatom microflora for both community research and monitoring programmes in marine ecosystems.

We examine the relationship of biomass B and length L in the eastern oyster Crassostrea virginica by focusing on the scaling exponent b in the allometric equation B = aLb using four datasets: Delaware Bay, Chesapeake Bay, Galveston Bay and a regionally extensive compilation from the NOAA Mussel Watch Program. The average value of the scaling exponent in Delaware Bay and Chesapeake Bay is about 2. For Galveston Bay, the value is distinctly higher, near 2.6. Over all Mussel Watch sites, the value is again near 2. Within Delaware Bay, the salinity gradient exerts an important effect. Shells are longer for their meat weight at lower salinities. The range of scaling exponents revealed by Mussel Watch data is exceedingly large (b < 1 to >3). Scaling exponents below 2.5 are unusual in bivalves. Among bivalves, only other oyster taxa have comparably low scaling exponents averaging near 2. We propose that oyster biomass routinely scales nearer the square of the length rather than the cube and that this is a constraint imposed by the exigency of carbonate production for reef maintenance and accretion in the face of high rates of taphonomic degradation. The adaptation as a reef builder requires the formation of carbonate that rapidly breaks down, thus requiring that carbonate produced be maximized. A biomass-to-length scaling exponent of 2 provides a mechanism to maximize shell production relative to biomass, while at the same time providing maximum surface area for the all-important settling of oyster spat to maintain the population.

Zoantharians are one of the least studied orders of benthic cnidarians of the Persian Gulf. A survey and molecular analysis was conducted to determine zoantharian species diversity in the Persian Gulf. For this purpose, 63 colonies of zoantharians were collected from Hengam and Larak Islands in the Strait of Hormuz and some morphological characteristics of each specimen were recorded, i.e. sand encrustation, polyp shape and colour, oral groove, oral zone and oral disc colours as well as tentacle number and colour. After DNA extraction, mitochondrial 16S ribosomal DNA (16S rDNA) and cytochrome oxidase subunit I (COI) were amplified by polymerase chain reaction (PCR). Based on obtained 16S rDNA and COI gene sequences, five putative species-level clades were identified: Zoanthus sansibaricus (N = 30), Palythoa tuberculosa (N = 12), Palythoa mutuki (N = 2), Palythoa aff. mutuki (N = 18) and Neozoanthus sp. Iran (N = 1). While the first three are known species, the last two were potentially novel undescribed species. Palythoa aff. mutuki has an external appearance similar to Palythoa mutuki. However, mitochondrial DNA sequences obtained from these specimens placed them in a previously undescribed species group. The Neozoanthus specimen was morphologically and molecularly different from other described Neozoanthus species. This is the first record of this genus from the Persian Gulf and neighbouring areas. Since there is not much work on zoantharians identification in the Persian Gulf, further sampling and investigation is needed to speculate on the accuracy of these potentially new species and to complete the knowledge of zoantharian diversity in this area.

Age and growth of Agassiz's parrotfish Sparisoma frondosum captured off Brazil (Pernambuco) were estimated using sagittal otoliths from 251 specimens. Sex of each specimen was determined and showed that 130 specimens were females (13.1 to 36.8 cm TL) and 121 were males (17.5 to 36.6 cm TL). The otolith marginal increment analysis indicated a single translucent ring formed every year. Parameters of growth curves were derived for the von Bertalanffy (VBGF) and Gompertz models. Based on the Akaike information criterion (AIC), both models were suitable for describing the growth of this species. VBGF parameters were estimated for males L ∞ = 39.74 cm TL, K = 0.22, t 0 = −1.63 years, females L ∞ = 32.38 cm TL, K = 0.44; t 0 = −0.23 years; and for the sexes combined L ∞ = 33.66 cm TL, K = 0.41, t 0 = −0.27 years. The study showed that 55% of individuals were 3 and 4 years of age, with maximal age of 9 years. Mature females (>17.6 cm TL) accounted for 45% of the sample. The age at first maturity for females was 1.6 years. For males the size at first maturity was not determined as immature individuals were not present in the overall sample. Also, primary males (PM) and specimens with gonads undergoing sexual transition were not found. The age structure and growth parameters for S. frondosum are an important contribution to the assessment of the state of exploitation of this species.

In the present work we describe nine saccular otolith morphometric indices (circularity, rectangularity, aspect ratio, percentage of the otolith surface occupied by the sulcus, percentage of the sulcus length occupied by the cauda length and ostium length, otolith length relative to the length of the fish, rostrum aspect ratio and percentage of the rostrum length occupied by the otolith length) of 41 species of the Tripterygiidae family collected mainly from New Zealand, Australia, Chile, South Africa, Mediterranean Sea and North America. The principal component of analysis showed that the indices that best explain the variability between species were related to sulcus and rostrum morphometry. According to cluster analysis, otolith morphometry could reflect the diversity of microenvironments for some genera such as Notoclinops and Forsterygion, while this does not happen to genera like Enneapterygius and Ruanoho. The discriminant analysis showed that the species Helcogrammoides cunninghami, Karalepis stewarti, Lepidoblennius haplodactylus, Notoclinus compressus, Ucla xenogrammus can be discriminated by using the morphometric indices. Two new indices related to the sulcus that were of great value for the discrimination of these species are described for the first time. This information will be a useful tool for palaeontological, taxonomic and trophic ecology studies.

Human activities have increasingly affected biodiversity in the Mediterranean Sea. Data on the distribution and abundance of species allows researchers to assess the possible degradation of wild populations. These data could act as a baseline to assess the magnitude of the effects of human activities on a bioindicator species. The distribution and relative abundance of the south-western populations of the endemic Astroides calycularis in the South Iberian Peninsula were studied to establish a baseline for future studies. The rocky shoreline was studied at a depth range of 0–12 m, including more than 650 km of Spain's Andalusian coastline. The species was present in 135 of the 585 dive points sampled. ANOVA analysis showed differences in depth in the four provinces studied, and there was no interaction between the two factors. As human activities on the Mediterranean coast are reducing the A. calycularis populations, a baseline on marine populations is greatly recommended for monitoring, assessment, and management studies, especially for endangered or bioindicator species. This baseline could be useful as a reference tool to assess the effects of human activities on marine biodiversity, including global change.