A floristic study of marine macrophytic algae and Cyanobacteria in the splash and intertidal zones at Luhuitou reef, Sanya Bay, Hainan Island, China, was conducted during the rainy and dry seasons of 2008−2012 utilizing 148 of the most common species. Macrophytic algal diversity increased from the splash zone to the low intertidal zone, while cyanobacterial diversity decreased. In the upper and middle intertidal zones, the dominant species (primarily highly productive ephemerals) changed frequently throughout each year. In the low intertidal zone, the dominant species (mainly annual fleshy, foliose and coriaceous forms) also changed. In the dry season, species numbers were 33% higher than in the rainy season. During the rainy season, Cyanobacteria dominated the splash zone, while green and red algae dominated in increasing numbers from the upper to the low intertidal zones. During the dry season the splash zone was devoid of all macrophytic algae, and only one species of Cyanobacteria survived. In the upper intertidal, Cyanobacteria and red algae prevailed, while in the mid and low zones, red and green algae were the most diverse. In spite of heavy pollution in Sanya Bay, there was no evidence of dramatic changes in species numbers or composition, and the marine flora was similar to that of unpolluted regions in the Indo-Pacific.

The effect of polarized light on the shade-seeking behaviour of the ophiuroid Ophioderma brevispinum was investigated at the Keys Marine Laboratory, Long Key, Florida, USA. Animals were collected and placed in a partially shaded arena. When the arena was illuminated with unpolarized light, the number of animals settling under the shaded portion of the arena was not significantly different from random (N=30, P>0.3). When the arena was illuminated with linearly polarized light, the number of animals settling in the shaded portion of the arena was approximately double what would be expected in a random distribution (N=30, P<0.001). The results are further evidence that O. brevispinum is sensitive to polarized light and are consistent with the hypothesis that polarized light may be used by the animals as an indicator of harmful levels of solar ultraviolet radiation.

Killer whales (Orcinus orca) have a cosmopolitan distribution, yet little is known about populations that inhabit tropical waters. We compiled 34 sightings of killer whales in the Bahamas, recorded from 1913 to 2011. Group sizes were generally small (mean = 4.2, range = 1–12, SD = 2.6). Thirteen sightings were documented with photographs and/or video of sufficient quality to allow individual photo-identification analysis. Of the 45 whales photographed, 14 unique individual killer whales were identified, eight of which were re-sighted between two and nine times. An adult female (Oo6) and a now-adult male (Oo4), were first seen together in 1995, and have been re-sighted together eight times over a 16-yr period. To date, killer whales in the Bahamas have only been observed preying on marine mammals, including Atlantic spotted dolphin (Stenella frontalis), Fraser's dolphin (Lagenodelphis hosei), pygmy sperm whale (Kogia breviceps) and dwarf sperm whale (Kogia sima), all of which are previously unrecorded prey species for Orcinus orca.

The spatial distribution of Farfantepenaeus shrimp was analysed in the Laguna Madre of Tamaulipas, Mexico. Sampling was carried out on submerged aquatic vegetation (SAV) habitats at five sites located along the coastal lagoon. Two nocturnal surveys were conducted during winter in 2005 (January–February), collecting a total of 3268 shrimp individuals. SAV beds were composed of a mixture of drift algae (mainly Digenia simplex), attached algae (mainly Penicillus capitatus and Udotea occidentalis) and seagrass (mainly Halodule wrightii). Farfantepenaeus aztecus was more abundant (39.5%) than F. duorarum (36.8%), and the remaining 23.7% corresponding to small unidentified Farfantepenaeus spp. were classified as recruits. Abundance of F. aztecus was significantly higher at sites 2 and 4, whereas F. duorarum did not show significant distribution differences along the Laguna Madre. Recruits, juveniles and total shrimp tended to decrease significantly at the northern part of the lagoon (site 1), where substrate was dominated by drifting algae and seagrasses were scarce or absent. The abundance of shrimp was positively related to seagrass biomass and/or water temperature, whereas there was a negligible or negative relationship with algal biomass. With the exception of subadults, a significant positive linear relationship between seagrass and shrimp abundance was fitted, indicating an increase in number of individuals of both species with increasing seagrass biomass. This suggests that seagrass is the most important component of SAV beds influencing the abundance of F. aztecus and F. duorarum along this hypersaline coastal lagoon.

This study was conducted to clarify the seasonal variation of the chemical composition of the Tunisian Sardinella aurita with a focus on the total lipid content. The chemical composition showed a large fluctuation over years in response to various factors. For the entire fish, lipid content was lower in July (2.50%), but higher in November (10.25%). It varies with seasons in inverse proportion to water content. Interestingly, it was found that red muscle have much higher lipid content than white muscle and the entire fish body. The major fatty acids in S. aurita lipids were palmitic acid, palmitoleic acid, eicosapentaenoic acid, docosahexaenoic acid and myristic acid. Palmitic acid comprised the main proportion (23.9%). The high amounts of saturated and monounsaturated fatty acids in the screened species are almost in agreement with other studies. Moreover, the percentage of omega-3 fatty acids (25%) was very similar to that in oil production commercial fish.

The occurrence of Mytilicola intestinalis in populations of mussels in south-west England is recorded and compared with previous data. Since 1955 there have been two main changes in the distribution of Mytilicola: (a) it has invaded all the major estuarine mussel populations on the Bristol Channel coast, and (b) many previously uninfested open-coast populations all round the peninsula are now lightly infested. It is suggested that differences in infestation levels between estuarine and open-coast populations of mussels are due primarily to differences in the degree of exposure to wave action although factors such as size, population density and location of the hosts also influence infestation. The chance of the establishment of breeding pairs of Mytilicola depends on the parasite population size and its distribution through the host population

In the first publication under the above general title the seasonal changes in sea water were studied, but as explained previously it was not possible to regard all the data as of an equal degree of accuracy. For this and other reasons the seasonal changes were further traced in the hydrographical cruises up to October, 1922, when the approach of the winter equilibrium made it profitless for some months to continue. Since, however, at times from April to September the changes are relatively rapid it may be advisable to follow up the matter during the period mentioned at shorter intervals.

The baited remote underwater video technique (BRUVS) was used to compare fish assemblages at three sites with different habitat characteristics: sandy bank (SB), rock reef (RR) and degraded coral reef (DCR) in Port Essington, Garig Gunak Barlu National Park, Northern Territory, Australia. The Carangidae family dominated, representing 35% of all recorded fish. The highest species number was recorded at RR followed by DCR and SB. The highest total fish number was recorded at DCR followed by SB and RR. Fish assemblages from all three sites are clearly different at high confidence level, but still overlapping and higher overlapping was found between SB and RR. Fish assemblages at all three studied sites contained some coral-associated species, fish fauna was less rich compared to coral reefs in the mouth of the bay and fish assemblages were noticeably different from typical coral fish communities. None of the fish assemblages at studied sites were presented by the ‘pure’, single habitat-associated association of species—at all three sites fish communities were a mixture of fish with various habitat preferences. Reef-associated species have a larger proportion at DCR and at RR their habitat complexity was higher; still soft-bottom habitat fish make substantial fractions in fish assemblages at both DCR and RR. Similarly, fish usually identified as ‘reef associated’ were found in notable proportions on SB. Fish with wide distribution and low selectivity in habitat preferences comprised a significant part in fish assemblages at all studied sites. In this study the BRUVS technique worked well in the area where diving visual surveys were impossible to implement because of high water turbidity. Another advantage of this method is the non-impact nature of visual survey; they can be used in long-term monitoring of fish assemblages at reference sites.

Bathymetric distribution data were compiled on benthic Medusozoa (Cnidaria) of the Bay of Biscay and nearby seas. The area of study extended from 42°N to 48°30′N, and westwards to 10°W. The depth range of each species was traced in a review of the literature. The number of species in each of several depth zones is summarized here: intertidal, intertidal–30 m, 30–100 m, and thereafter at 100 m depth intervals throughout the entire column (0–5000 m). Some 200 species were included (six Scyphozoa, four Staurozoa, 190 Hydrozoa). Of these, 196 could be ascribed to the Coastal Realm (0–200 m) (118 exclusives; 60% of the fauna) and Deep Benthic Realm (200+m) (31 exclusives;16%), with 47 species inhabiting both (24%). Eighty-eight species (45%) were present intertidally. Biodiversity was highest above the summer thermocline (30 m) (133 species, 67%), and no species have been recorded from depths greater than 4706 m. Beyond the thermocline, biodiversity dropped with increasing depth. A significant change occurred in the 30–100 m interval (123 to 78 species; Distinctiveness=51%), although all intervals down to the 300 m isobath exhibited substantial changes. Most species in the Deep Benthic Realm thrive on the upper part of the slope (200–800 m; 50 species). Biodiversity appeared homogeneous across wide bathymetric ranges in deep bathyal and abyssal regions, perhaps due to unique vertical biocenological units. Thus, 15 species are known between 1400 and 2000 m, and four between 3100 and 4300 m. Fifty-four species were considered eurybathic (34%), with some showing impressive bathymetric ranges of over 4000 m, but most species were stenobathic (106, 66%).

As with data on benthic medusozoans from South Africa, the north-western Atlantic, the Arctic, and the warm western Atlantic (Bermuda), bathymetric biodiversity was highest in the first 100 m, with a substantial drop below that in species numbers on the shelf and at the beginning of the bathyal. While numbers of species may vary widely from one geographical region to another, such variations are due to differences in biodiversity in the upper 100 m. Hydroid species richness in the deep bathyal and abyssal is similar and always low. Worldwide, benthic medusozoan biodiversity is highest at shallow depths, and these organisms normally seem to be minor components of deep benthos. Very likely, the graph of biodiversity at increasing depth is similar worldwide for the Hydrozoa.

The polychaete assemblages inhabiting the coastal waters of the Oualidia lagoon were studied during winter 2013 and summer 2013. Taxonomic composition and diversity were determined at 43 sample sites. Among the 13 species of polychaetes recorded, 10 were newly reported for Oualidia lagoon. Hediste diversicolor and Capitella sp. were the most abundant taxa in both seasons. Temperature and salinity were higher, and chl-a and OM were lower, in summer than in winter. The structure of the polychaete assemblages was characterized by forming three main clusters, either based on sampling stations or on polychaete species. These clusters were organized according to a downstream gradient, with the stations having fine sediments and a H. diversicolor assemblage in the inner lagoon being replaced by stations with medium grain-sized sediment and a Capitella sp. assemblage in the mid-lagoon, which were in turn replaced by stations having sandy sediments and assemblages dominated by Glycera alba (winter) and P. africana (summer) in the areas closer to the lagoon inlets. The shift was, in fact, from a classical, brackish, lacunar assemblage to two different, temporal aspects of a marine assemblage (close to the inlets), with a transition assemblage in between. This corresponded with a typically paralic spatial structure whose main descriptors responded to a confinement gradient. Despite the absence of a river, the organization of the polychaete assemblages closely resembled that of an estuarine system, with the tidal regime playing a major driving role.

This study aimed to augment existing knowledge of the reproductive characteristics of Donax trunculus through analysis of timing variations and the influence of shell size on partial fecundity (PF) during the reproductive period. To achieve this objective, two reproductive timing characteristics were also studied: size at first maturity (SL50) and the reproductive cycle using histology and image analysis techniques. SL50 was 10.83 mm for females and 10.86 for males. Donax trunculus showed a continuous and simultaneous release of gametes and high oocyte regeneration ability during the reproductive period (from February to July). These reproductive characteristics impeded the estimation of total fecundity. However, throughout the reproductive period an increasing pattern of PF was observed followed by a significant drop at the end of the same period, which could be quantified (293,390 of vitellogenic and ripe oocytes). At the same time PF quantifications allowed for predicting and estimating the influence of shell length (SL) on the reproductive output as a function of oocyte typology (PF = 4.12 + 3.96 SL; r2 = 0.86; all types). Levels of prevalence of a digenetic trematode-like parasite with castrate ability fluctuated between 0–20% depending on the time of the year and sex. In addition, the possible consequences of two different scenarios of population size structure on the reproductive output were simulated, and highlighted how beach areas supporting high levels of anthropogenic pressure (Isla Canela) could compromise future recruitments, producing 84% less oocytes than a beach with a lower level of disturbance (Doñana).

Mussels are typical macrofouling organisms in the world. In this study, the interaction between the settlement of Mytilus coruscus plantigrades and bacterial community on coloured substrata was determined. Bacterial communities in biofilms developed on seven coloured substrata were analysed by Illumina Miseq sequencing. The mussel settlement response to coloured substrata with no biofilms was also examined. Flavobacteria, Alphaproteobacteria and Gammaproteobacteria were the first, second and third most dominant groups in seven biofilm samples. The results suggest that the inducing activities of these biofilms on plantigrade settlement varied with coloured substrata and the lowest percentage of settlement was observed on biofilms on the green substratum. High-throughput sequencing showed that bacterial community in biofilms also changed with the substratum colour. No significant difference in the inducing activity on plantigrade settlement was observed between the coloured substrata with no biofilms. Thus, difference in plantigrade settlement response may be correlated to the changes in bacterial community on coloured substrata. This finding extends current knowledge of interaction among mussel settlement and bacterial community variability.

The stomach contents of 69 Mediterranean spearfish Tetrapturus belone collected in the Strait of Messina, central Mediterranean Sea were examined. Of the total specimens, caught by harpoon, only three stomachs were empty. Their diet consisted mainly of pelagic fish and cephalopods. The most important piscine prey belonged to the families of Belonidae, Clupeidae and Scomberesocidae. Cephalopods were mainly represented by Tremoctopus violaceus in terms of per cent weight and by Illex coindetii in terms of per cent frequency of occurrence. Tetrapturus belone is an active predator on epipelagic fast-moving prey and school-forming species. Its ecological role is similar to that of other large pelagic species which share the same environment.

The red-blooded limpet ‘Shinkailepas’ briandi (Neritimorpha: Phenacolepadidae) is one of the commonest gastropod species at deep-sea hydrothermal vents on the Mid-Atlantic Ridge (MAR). We investigated its population connectivity along MAR as the first such study for gastropods and explored the importance of larval migration for the distribution of vent-endemic animals. Our analyses, based on 1.3-kbp DNA sequences from the mitochondrial COI gene, showed a panmictic population throughout its geographic and bathymetric ranges that span from the northernmost and shallowest Menez Gwen vent field (38°N; 814–831 m depth) to the southernmost and deepest Ashadze field (13°N; 4090 m). Early development of this species is presumed to have a long pelagic duration as a planktotrophic larva; the hatchling with a shell diameter of 170–180 μm attains a constant settlement size of 706 ± 8 μm (mean ± SD). Retention of eye pigmentation in newly settled juveniles, along with the genetic panmixia, suggests that the hatched larva of ‘S.’ briandi migrates vertically to the surface water, presumably to take advantage of richer food supplies and stronger currents for dispersal, as has been shown for confamilial species at hydrothermal vents and cold methane seeps.

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.

Presence and habitat preference of two pelagic fish species—Mola mola and Ranzania laevis—are investigated from all available records obtained in the Adriatic from 1781 up to today. Absence of systematic investigations is overcome by relating their occurrences to the long-term meteorological and oceanographic data sets representing local conditions and processes. Seasonal and interannual distributions of these two species are significantly different and point to a possible different causes of their appearance. On the seasonal scale almost all findings of M. mola, with only a few exceptions, are from the warm part of the year, whereas R. laevis is appearing throughout the year with the highest number of individuals in December. Analysis of the interannual meteorological and oceanographic conditions indicates that occurrence of M. mola coincides with the sea warming, whereas the oceanographic conditions favourable for appearance of R. laevis are more complex and could be related to the abrupt change in the large scale atmospheric conditions. Changeable atmospheric conditions coincided with increased productivity in the Adriatic and increased number of zooplankton and small pelagic fish, which are the main food for R. laevis.

The dynamics of intertidal populations of the starfish Asterias rubens, living in contrasted habitats and over a broad geographical range, were studied from March 2000 to November 2002 using modal analysis. As only 1 juvenile (first year after recruitment) and 1 adult (subsequent years) modes could be distinguished; only juvenile growth was quantified. Concomitantly, experiments were carried out to test several factors assumed to influence juvenile growth: food quantity and quality, emersion, salinity variations and temperature. Three different juvenile growth patterns were evidenced: (1) a fast and protracted growth linked to high food availability and lack of disturbance; (2) a winter cessation of growth likely due to a seasonal increase of emersion-related stress and salinity variations; and (3) disrupted juvenile dynamics, which was encountered in 2 populations. In the first one, estuarine salinity conditions limited growth and, combined with food depletion, led to the extinction of the population. In the second one, wave action confined most of the population to a restricted area with low food levels. In the third scenario, intraspecific competition for food was probably at the source of an unusual growth pattern in which most juveniles did not grow while a small proportion achieved a medium growth rate.

The pattern of changes in the macrobenthic community was studied along the south-east coast of India from the estuary to continental slope. A transect perpendicular to the coast was selected for sampling in estuary, inshore region, continental shelf and continental slope. Sampling was done in 16 stations in the depth range of 1.7–1000 m. The community structure was characterized in terms of species composition, abundance, diversity and feeding type. Four taxa were encountered in the study area comprising 181 species of polychaetes, 65 species of molluscs, 47 species of crustaceans and six species of ‘others’ (four echinoderms and two cnidarians). Polychaetes were found to be dominant at all the depths constituting 53.89% of the total abundance and 60.54% of the total number of species. Number of species and Shannon diversity of macrobenthos increased from estuary to shelf region and then decreased. The abundance was found to be maximum in the estuary and minimum in the slope. Carnivorous species were found to be dominant in the estuarine and inshore regions and surface deposit feeders in the shelf and slope regions. Dissolved oxygen decreased gradually from 30 m depth and beyond 150 m the decrease was pronounced due to the presence of the oxygen minimum zone. The distance based linear model (DISTLM) showed the environmental variables to explain about 76.45% of the total variability in macrofaunal distribution. Among the various environmental parameters, total organic carbon, depth and salinity explained more variability than others. Gradual change in community structure was quite evident with increase in depth.

This study describes phenotypic and genotypic variations in the planktonic copepod, Centropages typicus (Copepoda: Calanoida) that indicate differentiation between geographical samples. We found consistent differences in the morphology of the chela of the sexually modified fifth pereiopod (P5) of male C. typicus between samples from the Mediterranean, western North Atlantic and eastern North Atlantic. A 560 base pairs (bp) region of the C. typicus mitochondrial cytochrome c oxidase subunit I (COI) and a 462 bp fragment of the nuclear rDNA internal transcribed spacer (ITS) tandem array were analysed to determine whether these morphological variations reflect population genetic differentiation. Mitochondrial haplotype diversity was found to be high with 100 unique COI haplotypes among 116 individuals. Analysis of mtCOI variation suggested differentiation between the Mediterranean and Atlantic populations but no separation was detected within the Atlantic. Intragenomic variation in the ITS array suggested genetic differentiation between samples from the western North Atlantic and those from the eastern North Atlantic and Mediterranean. Breeding experiments would be required to elucidate the extent of genetic isolation between C. typicus from the different population centres.

Although there are no previous descriptions of the habits of chirostylids in the North Atlantic, it is likely that species in the genera Uroptychus, Eumunida and Gastroptychus have close ecological ties with deep-sea corals since they have all been recorded in trawl samples containing corals from >200 m depth. We analysed in situ distribution of Gastroptychus formosus and potential hosts using a ROV at a range of north-eastern Atlantic sites and found that this species forms a close association with deep-sea corals that resembles the chirostylid–anthozoan associations reported in shallow Indo-Pacific waters. We update the known distribution for G. formosus, confirming that it is an amphiatlantic species that occurs along the Mid-Atlantic Ridge at least as far south as the Azores and along continental margins from the Canary Islands to Scotland at depths of 600–1700 m. The adults have very specific habitat preferences, being only found on gorgonian and antipatharian corals with a strong preference for Leiopathes sp. as a host. This highly restricted habitat preference is likely to render chirostylids vulnerable to the impacts of demersal fishing both directly, as by-catch, and indirectly through habitat loss.