The composition and structure of a molluscan assemblage inhabiting an outcrop with a coralligenous community was studied in southern Spain. A total of 117 molluscan species were identified, with gastropods as the dominant group. Calyptraea chinensis was the dominant species and the family Conidae presented the highest number of species. The Shannon–Wiener diversity index and the Evenness showed non-significant changes between cold and warm months, displaying high values (~4 bits and ~0.8 bits respectively). Some of the dominant and/or frequent species are strictly associated with coralligenous-building organisms, such as Neosimnia spelta with gorgonians. Regarding trophic guilds, carnivores are the dominant group, followed by filter feeders due to the high abundance of C. chinensis. Regarding biogeographical distributions, most of these species (<95%) are widely distributed in European waters, the number of strictly Mediterranean species being very low. The Alboran Sea represents the distributional limit towards the Mediterranean for some species found in this bottom, such as the Atlantic Bela powisiana. Rocky–coralligenous bottoms are scarce in the western Alboran Sea but support a high species richness molluscan assemblage, displaying higher diversity values than the surrounding soft bottoms and increasing the biodiversity at local scale. This high biodiversity is partly explained by the coexistence of different taxa with contrasting biogeographical affinities promoted by the geographical location of the area. Due to this, conservation efforts should be required to protect this stretch of coastline where one of the most biodiverse invertebrate assemblages along the European coasts can be found.

Saroma-ko Lagoon, the largest body of water that has complete ice coverage during winter in Japan, was not completely covered by ice in the winter of 2009. This condition is considered to be a result of the progression of global warming. A bloom of large diatoms was observed in the ice-free area between February and April. This early spring bloom seemed to have started in the latter part of January, and lasted for about three months. The maximum chlorophyll-a (Chl a) concentration of about 10 mg m−3 was observed in March, and was similar to the level of 5–20 mg m−3 previously reported for the ordinary spring bloom in Saroma-ko Lagoon. The maximum primary production of 786 mgC m−2 day−1 and the maximum Chl a-specific primary production, an index of the phytoplankton growth rate, were also found in March. Species changes from Thalassiosira spp. to Chaetoceros spp. were observed during the bloom. This early spring bloom could extend into the ordinary spring bloom period. Its duration was obviously longer than that of the spring bloom, which is typically about one month. These results show the phytoplankton condition that could be expected during winter and spring as global warming progresses.

Two distinct species have been recently recognized for the genus Sotalia: S. fluviatilis, occurring in the Amazon River basin, and S. guianensis, from Honduras (15°58′N and 85°42′W) to Santa Catarina State (Florianópolis, southern Brazil—27°35′S and 48°34′W). For the first time the sternum and the appendicular skeleton of the two species of the genus Sotalia are compared. A comparative osteological work was performed with marine samples (from the States of Ceará, north-eastern and Santa Catarina, southern regions of Brazil) and riverine samples (Amazonas State) in relation to metric characters (scapula, flipper and sternum). There was a clear distinction of two species in relation to postcranial skeleton in the morphometric analysis (canonical variate analysis) presented. The flipper and the glenoid cavity of the scapula were proportionally wider in the fluvial species. The sternum, however, was smaller in this species in relation to the maximum width of the manubrium. Nevertheless, this structure still needs to be further studied.

The soft-bottom zoobenthic community structure of Izmir Bay was examined seasonally at eight stations (depth-range: 19–67 m) in 2009. A total of 427 species were found. Polychaeta had the highest number of species (50% of total species) and individuals (75%), whereas Echinodermata possessed the highest biomass (47%). The number of species varied from 3 to 79 (0.1 m−2), the density from 60 to 5360 ind.m−2, and the biomass from 1 to 530 g.m−2. The most numerically dominant species were the polychaetes Aricidea claudiae, Streblospio gynobranchiata, Levinsenia demiri and Sternaspis scutata. The distribution of zoobenthos was strongly related to spatial differences in total organic carbon, sediment texture and depth among different regions of the bay rather than temporal differences among seasons. However, significant seasonal variability in community structure (mainly differences in the relative abundance of species) was present. The inner region of the bay can be classified as ‘poor’ or ‘bad’ based on the results of biotic indices (H′, AMBI, m-AMBI and BENTIX). Among biotic indices, only H′ and m-AMBI appeared to be capable of explaining the bay's benthic quality status. Thirteen alien species were also found. Streblospio gynobranchiata, Prionospio pulchra, Pseudopolydora paucibranchiata and Polydora cornuta formed dense populations in the inner most polluted part of the bay and are considered to be new pollution indicator species in the eastern Mediterranean Sea.

Common seals Phoca vitulina give birth in the Wadden Sea area during the summer months. We provide evidence that the pupping season has advanced in date in this region. Analysis of stranding dates of recently-born, orphaned pups admitted for rehabilitation, revealed a shift of, on average, 0.88 days per year over the period 1974–2008, yielding a total advance of 26 days. Although the pupping season has become progressively earlier, there were no indications of any negative impact on the weight of the pups, nor was there an increase in the proportion of seals with a lanugo coat. These observations suggest that the most likely explanation for the change in phenology of the pupping season is a corresponding change in the timing of cessation of the period of delayed implantation. It is suggested that shifts in phenology could reflect an adaptive response of the animals to altered local circumstances. The latter may in turn be induced by larger scale phenomena such as food availability or climate change.

The study aims to provide the first detailed account of the diversity and composition of the community associated with biogenic reefs formed by serpulid worms. Ten reefs (aggregations of calcareous Serpula vermicularis tubes), spanning a broad size-range, were collected from Loch Creran, Scotland, a Special Area of Conservation designated principally for the protection of its biogenic reefs. Total faunal abundance was strongly linearly related to reef weight, whilst taxon richness exhibited a hyperbolic relationship with reef size. 278 taxa were recorded from the ten reefs, with a reef of 0.1 m2 area supporting 163 taxa and 12756 individuals, which appears to represent considerable augmentation of diversity and abundance for sedimentary areas of the loch where the reefs occur. The reef assemblage was dominated by polychaetes (94 taxa), molluscs (70 taxa) and crustaceans (45 taxa). Species composition varied with reef size, although reefs greater than 25 cm width exhibited relatively little variation. In comparison with other biogenic polychaete habitats, S. vermicularis reefs appear to support a highly diverse community, which exhibits a high degree of similarity with that found in association with aggregations of the horse mussel, Modiolus modiolus. The presence of the Connemara clingfish, Lepadogaster candollei, rarely recorded at such a northerly latitude, on several reefs, indicates that the reef habitat may provide a stronghold for this species at the edge of its biogeographical range.

We identified and quantified the benthic macrofauna associated with decomposing leaves of Rhizophora mangle and Laguncularia racemosa, to observe the differences in the abundance and composition of macrofauna between these mangrove species, and to examine whether the abundance and composition of organisms changed with different stations and collection times. Benthic macrofauna, mainly polychaetes and amphipods, were recorded from the fifth day after the installation of the experiment. Annelids including Oligochaeta and Polychaeta were the most numerous group. Crustacea were represented by peracarids (Amphipoda and Tanaidacea) and decapods. Of Hexapoda, only juvenile forms and pupae were present. The most abundant polychaete species was Perinereis brevicirrata, followed by Capitella cf. capitata, Heteromastus filiformis and Neanthes succinea. In one-way analysis of variance (ANOVA) there were no statistical differences between the macrofauna of mangrove species, seasons, or collection times, except among collection times for R. mangle litter bags. Two-way ANOVA showed homogeneity for macrofauna abundance between the groups of collection times for both mangrove species. The richness was similar for R. mangle litter bags, and showed a significant difference for L. racemosa. Abundance and richness were also similar between the mangrove species. The colonization of detritus by benthic invertebrates followed a successional sequence during the decomposition process. This suggests that the density of these organisms and their foraging behaviour affected the decomposition rates of leaves of R. mangle and L. racemosa.

In this work we describe Actinia ebhayiensis sp. nov. from South Africa. The species is externally similar to the type species of the genus, Actinia equina, from which it can be distinguished by nematocyst and allozyme data. Actinia ebhayiensis has a smooth, red column, with well-delimited parapet leading to a deep fosse where conspicuous blue acrorhagi can be found. Tentacles and oral disc are crimson red, and the pedal disc has a lighter pink colour. The microbasic p-mastigophores and b-mastigophores of the mesenterial filaments of the new species are significantly smaller than those of A. equina. Actinia ebhayiensis can also be clearly distinguished from other species of the genus in nematocyst measurements, genetic data and muscle morphology.

The association of invertebrate communities with macroalgae rafts has received much attention over recent decades, yet significant gaps in our knowledge remain with respect to the colonization process. Using laboratory-based experiments and in situ field trials in Strangford Lough, Northern Ireland, this study investigated whether members of the known rafting genus Idotea (sub-phylum Crustacea; order Isopoda) could effectively colonize rafts after shore seaweed detachment, or if their presence merely reflected a passive marooning process. Test tank arenas were used to identify traits that may influence the rafting potential of the dominant shore species Idotea granulosa and the well known rafter Idotea baltica. When released mid-water, I. granulosa initially ascended and associated with floating seaweed whereas I. baltica tended to descend with no clear habitat association. These findings conflict with the differential distribution of these Idotea species among rafts and shore algae, thus highlighting the complex nature of the potential of organisms to raft. In the field we considered the relative ability of different Idotea species to colonize tethered rafts composed of Ascophyllum nodosum and Fucus vesiculosus, cleaned of all vagile organisms and deployed at locations adjacent to established intertidal Idotea species populations. At the end of the experiment (after 44 days) rafts were inhabited by known rafting and shoreline species, confirming that colonization can occur after algal detachment. Previously considered shoreline species on occasion outnumbered well known rafters suggesting that a wide range of Idotea species can readily avail of macroalgal rafts as a potential dispersal mechanism or alternative habitat.

This study determined the spatial and seasonal density, number of genera, genera composition, maturity index and trophic structure of free-living nematode assemblages in the subtidal waters of the northern Beibu Gulf, South China Sea, and explored whether these five biotic characteristics were related to various environmental variables. Based on the data derived from samples collected seasonally at nine stations, the mean densities of nematodes decreased from alongshore to offshore station in the northern Beibu Gulf. However, the number of nematode genera increased from alongshore to offshore station. Non-parametric multidimensional scaling analysis showed no clear seasonal changes for nematode assemblages in most sampling stations. Higher densities of the genera Elzalia and Tricoma were found in offshore sampling stations, and a higher density of the genus Cheironchus was found in alongshore sampling stations. The mean percentage of each feeding type compared to the total numbers was highest in epigrowth feeders (2A), second highest in non-selective deposit feeders (1B), third highest in predators (2B), and lowest in selective deposit feeders (1A). There were significant negative correlations between nematode density and water depth and temperature; significant positive correlations between the number of nematode genera and water depth and salinity; and significant negative correlation between the maturity index of the nematode assemblage and organic matter. BIOENV analysis indicated that water depth, salinity, pH, median sediment particle size and organic matter were the most correlated combination of environmental variables affecting the nematode assemblages.

Upon infesting the hermit crab Pagurus proximus the parasitic barnacle Peltogaster reticulatus typically forms a single externa on each host. In vivo, histological and histochemical study revealed that most P. reticulatus with a single mature externa also exhibited three or four primordial externae and several buds of earlier developmental stages. It is shown that stolon buds and primordial externae in P. reticulatus internae intensively express alkaline phosphatase activity, the classical histochemical marker for mammalian embryonic stem and primary germ cells. Ovaries of the most developed primordial externae were filled with growing oocytes, so the process of oogenesis begins in the externa rudiments of P. reticulatus before the externae appear on the surface of the host body. Since the interna, which is connected to the mature externa, also integrated three or four additional primordial externae and several earlier buds, P. reticulatus, a non-colonial species based on the common presence of a single externa in each host, appears to have a hidden colonial organization at the parasitic stage of its life cycle.

Baited traps with a 5 mm diameter opening were deployed 9 cm off the seabed in the Cape d'Aguilar Marine Reserve, Hong Kong. In contrast to analogous studies from boreal waters, lysianassoids accounted for 0.5% of the total number of trapped hyperbenthos. Species of Tisbe (Copepoda: Tisbidae), Ceradocus (Gammaridea: Melitidae), Nebalia (Leptostraca: Nebaliacea), unidentified benthic ostracods, Neanthes cricognatha (Polychaeta: Nereidae) and a species of Lepidepecreum (Amphipoda: Lysianassoidea) were caught in a decreasing order of numerical importance. A spatial segregation of trapped fauna was identified between the reserve's shallow Lobster Bay (<–2 m Chart Datum (CD)) and deeper-waters (between –6 and–17 m CD) outside it. Ceradocus sp. monopolized the trapped fauna in the former area, while the other species were caught almost exclusively from the latter. Insignificant Ceradocus sp. catch differences between baited and control traps suggested that they functioned only as ‘habitat traps’ for this species. Almost all other organisms attracted to the bait were hyperbenthic scavengers. Their absence from the shallows might be due to the coarser and lower organic contents of the sediments, also related to faster flow rates here. Finally, we confirm that in subtropical Hong Kong, lysianassid amphipods are not as significant hyperbenthic scavengers as they are in boreal waters.

Sallow-skin horseshoe crabs (late juvenile Tachypleus tridentatus) from 30‰ salinity seawater were subjected to salinities ranging from 0‰ to 70‰ at 5‰ intervals for 7 days. They were returned to 30‰ salinity for 3 days for recovery. During this period, the survival rate, feeding rate, and body mass of the horseshoe crabs were measured. The sallow-skin horseshoe crabs survived well at 15‰–60‰ salinity, fed well at 30‰–55‰ salinity, gained mass at 0‰–25‰ salinity, lost mass at 45‰–70‰ salinity, and maintained mass at 30‰–40‰ salinity during salinity challenge. During the recovery period, the dehydrated (mass lost) horseshoe crabs rapidly gained mass, whereas the water-retaining (mass gained) horseshoe crabs rapidly lost mass. These results indicate that the sallow-skin T. tridentatus horseshoe crabs are osmoconformers and can tolerate a wide range of salinity changes, adapting gradually from inshore low salinity to offshore high salinity.

Phymactis papillosa is a rocky shore sea anemone that is commonly found in the Pacific Ocean, from the Gulf of California to Tierra del Fuego, and in the Mar del Plata region, Argentina. The genus Phymactis is closely related to Bunodosoma and, due to character plasticity, a number of misidentifications have occurred. Therefore, the presence of P. papillosa in Argentina has been doubted but the matter had not been investigated in detail. Here we analyse P. papillosa specimens from Argentina and compare them, using molecular and morphological markers, to specimens from the species' type locality. In a phylogenetic analysis using 19 allozyme markers and ribosomal internal transcribed spacers sequences of different sea anemone genera, including all West Atlantic Bunodosoma species, we have found that the specimens from Argentina were genetically divergent from P. papillosa from Chile and closely related to West Atlantic Bunodosoma species. The genetic and morphological analyses indicate that those specimens belong to a new species of the genus Bunodosoma, described here as B. zamponii sp. nov.

Temporal variation of hyperiid amphipod structure assemblages was studied on Isla Gorgona, eastern tropical Pacific (ETP) off Colombia between September 2005 and August 2006. Forty-six species were found during the entire sampling period: Hyperioides sibaginis, Lestrigonus bengalensis, Phronimopsis spinifera, Tetrathyrus forcipatus and Paralycaea gracilis dominated the assemblage, representing 92%. The dendogram based on the Bray–Curtis similarity index showed that the hyperiid assemblages were separated into two groups, which did not coincide with the seasonality described for the ETP (wet versus dry season). Rather, groups comprised wet (May to November) and dry season months (December to April). The first group included November, December, February and March. During these months, significantly higher hyperiid richness, diversity and abundance were found, although colder subsurface water temperatures in Gorgona were registered only during February and March. The other group included May to October and January, and was characterized by lower hyperiid diversity and abundance values. Significant correlations were found between hyperiid abundance and the possible gelatinous zooplankton hosts (medusae, siphonophores and salps). This study contributes to increasing knowledge of the zooplankton community in the Panama Bight, as well as of a poorly studied group in the ETP.

Aquarium systems allow technically sophisticated experiments that promise new opportunities to answer urgent questions about reef coral biology, for instance assessing the responses to decreasing environmental pH and/or increased temperatures. Over recent years, long-term culture and (predominantly asexual) propagation of corals has become possible in such systems. At present however, only limited data are available that clarify whether or not responses of the coral holobiont are dominated by the acclimatization to life in captivity or continue to reflect, for example, taxonomic differences seen in nature. We studied the diversity of the symbiotic algae in corals and sea anemones after long-term aquaculture by analysis of their small subunit (SSU) ribosomal DNA gene. A field sample of Acropora clathrata from the Arabian Gulf which was used as a control contained clade C zooxanthellae. The aquarium corals also harboured clade C symbionts, but sequencing of the SSU DNA suggested that the analysed animals host different subclades. A prevalence of clade C is also found among corals from the Indo-Pacific region, the origin of most of the aquarium samples. An individual of the temperate sea anemone Anemonia sulcata (viridis) contained clade A symbionts, similar to those found in nature, even after nearly 10 years of co-culture with sea anemones (Entacmaea quadricolor) and corals hosting clade C symbionts. The results indicate that the specific host–symbiont association occurring in nature appears to persist over >2 years timescales in captivity, with no mixing of symbionts between hosts maintained in the same aquarium or apparent selection of stress-tolerant symbiont strains such as clade D.

Extensive beds of the mussel Perumytilus purpuratus are a common feature of the mid-intertidal along the Chilean coast. The beds are an alternative stable state that results from the anthropogenic removal of the keystone predator Concholepas concholepas. The mussel beds constitute an important microhabitat that supports a large number of small mobile macrofaunal and meiofaunal species. This paper seeks to determine if the absence of extensive mussel beds within a Marine Reserve results in a reduced species richness. We used ‘live’ artificial mussel beds on plates to determine the species richness of fauna both inside and outside the Marine Reserve. There were no significant differences in the species richness (Smean) on plates inside and outside the Marine Reserve but there were differences with the natural mussel beds. Though the assemblages on the plates did not reach maturity ‘live’, artificial mussel beds could prove a useful tool for assessing the species richness of small mobile macrofauna and meiofauna.

Underwater image-based sampling procedures, using SCUBA, are compared using imagery collected from a temperate hard-substratum community. The effectiveness of a low-budget, high-resolution image mosaicing technique is assessed by comparing the relative efficiency of data collection, extraction and analysis among sampling procedures. In addition, a manipulative experiment tested whether the sampling procedures could detect the physical removal of 10% of the reef community. Overall, four factors were explored within the data: data collection media (stills and video), cover and community composition estimation techniques (visual cover estimation, frequency of occurrence and point extraction), change detection (pre- and post-impact) and depth (8, 14, 18 and 22 m). Stills imagery sampled the reef community at a higher image resolution than the video imagery, which enabled identification of more species and less-conspicuous benthic categories. Using the visual cover estimation technique, the stills imagery also had the greatest benefit in terms of efficiency and species identification. However, the experimental impact was detected using only the point extraction technique. The recommendations are that: (1) the image mosaicing technique is applied to fixed-station monitoring; (2) the point extraction technique be used for efficient and cost-effective monitoring at coarse taxonomic resolutions; and (3) survey depths remain constant over the duration of hard-substratum community monitoring.

The harbour porpoise is seriously depleted and threatened with extinction in the Baltic Sea. It is usually assumed that Baltic porpoises form a separate population unit, although the evidence for this has been disputed lately. Here, a 3-D geometric morphometric approach was employed to test a number of hypotheses regarding population structure of the harbour porpoise in the Baltic region. 277 porpoise skulls from Denmark, Sweden, Finland, Germany and Poland were measured with a suite of 3-D landmarks. Statistical analyses revealed highly significant shape differences between porpoises from the North Sea, Belt Sea and the inner Baltic Sea. A comparison of the directionalities of the shape vectors between these units found differences that cannot be attributed to a general, continual shape trend going from the North Sea to the inner Baltic Sea. These vectors indicate a morphological adaptation to the specific sub-areas. Such adaptation may be the result of the topographic peculiarities of the area with variable topography and shallow waters, e.g. in the Belt Sea porpoises, there may be a greater reliance on benthic and demersal prey. The present results show that isolation by distance alone is an unlikely explanation for the differences found within the Baltic region and thus support previously reported molecular indications of a separate population within the inner Baltic Sea.

Amphipods' assemblages living in the red algae communities were studied in Velikaya Salma Strait (Kandalaksha Bay, north-western White Sea) in the depth range of 3–11 m. Sampling sites were located along the depth and shore exposure gradients in the areas with a significant number of rhodophytes. In total 12 species of amphipods were found with Ampithoe rubricata and Crassicorophium bonellii being most common and abundant. Gammaropsis melanops and Pleusymtes glaber were revealed as subdominant species. As an algal grazer A. rubricata appeared to be the species most closely associated with various algal assemblages. Crassicorophium bonellii were found on substrates being a deposit feeder predominantly inhabiting mixed assemblages of red algae where deposition and accumulation of seston most likely took place. Gammaropsis melanops and P. glaber are known as grazers but they preferred the habitats with both red algae and sponges. None of the species can be considered as obligate inhabitants of red algae hosts. Ampithoe rubricata and C. bonellii occurred in red algae communities in the shallow area (about 4 m). The most diverse and quantitatively rich amphipod assemblages were found at depths of 8–9 m in the area protected from waves and surf by the islands. Three of the most common and abundant species A. rubricata, C. bonellii and P. glaber are considered as amphiboreal while most of the species associated with rhodophytes belong to the Arctic-boreal ones. Amphiboreal species are presumably adapted to a broader temperature-range, in particular to higher summer temperature, than the Arctic-boreal species; they most likely have an advantage when occupying biotopes at shallow subtidal depth with local conditions in the White Sea.