A new spionid polychaete, Malacoceros jennicus, is described from the crater of a hydrothermally active submarine volcano near Grenada in the Caribbean, Lesser Antilles Arc region. The new species is characterized by having prominent lateral frontal horns on the prostomium, paired eye spots, neurosetae that include simple capillaries, inferior sabre setae, numerous bidentate hooded hooks, and a pygidium bearing four digitiform anal cirri surrounding the anus. Worms were collected in regions of diffuse venting with a suction sampler deployed on an ROV. Specimens representing a range of sizes including sexually mature and reproductive individuals containing eggs and sperm were found. Stable isotope analysis of 13C and 15N indicate mixed feeding on photosynthetic and hydrothermal vent source material.

Two new species of polyclads are described from the continental slope of the Gulf of Mexico. Specimens of Didangia carneyi sp. nov. and Oligocladus bathymodiensis sp. nov. were collected from the Louisiana slope at 610 m and 650 m, respectively. Didangia carneyi sp. nov. was collected from a natural wood fall, and is characterized by the presence of tentacular and cerebral eyes, an interpolated prostatic vesicle provided with two muscular accessory prostatic vesicles, and large glandular cells that surround the male atrium. Oligocladus bathymodiensis sp. nov. has a mouth anterior to the brain, a few cerebral and pseudotentacular eyes, four pairs of intestinal branches, and a ventral anal pore. Specimens of this species were collected on the margin of a hypersaline cold seep in association with mussels of Bathymodiolus childressi. All type material is deposited at the Field Museum of Natural History, Chicago, Illinois, USA.

The biodiversity and distribution patterns of epiphytic hydroids were studied in kelp forests (composed of Laminaria digitata, Saccharina latissima and Alaria esculenta) located in an Arctic glaciated fiord (Hornsund, west Spitsbergen). In total, twenty-eight species were found colonizing algae, stones connected to holdfast, and overgrowing the surface of other animals associated with kelps. The characteristics of the algal host (e.g. algae species, age, rhizoid volume or biomass) did not show any effect upon hydroid species richness or species composition. High hydroid biodiversity was strongly dependent on microsubstrate heterogeneity. The highest biodiversity as well as frequency of hydroid occurrence were noted at a site located furthest from the glacier and characterized by the lowest sediment concentration and sedimentation rate. Sexual reproduction also seemed to be inhibited by glacier-derived disturbance. Of ten fertile species found at the ‘clearest’ site only two were fertile at sites under the strong influence of such perturbations. Potential physical drivers of species occurrence were linked to the activity of tidal glaciers, particularly to high loads of mineral sedimentation and iceberg scouring.

Ship strikes of large whales cause mortalities worldwide, but there is uncertainty regarding the frequency and species involved. We examined 130 records (from 1980–2006) of large whale strandings in Washington State. Nineteen strandings (seven species) had evidence of ship-strikes. Fin whales (Balaenoptera physalus) had the highest incidence of ante-mortem ship strike (five of seven, with the remaining two possibly post-mortem) and all but one occurring since 2002. Six grey whales (Eschrichtius robustus) suffered ‘possible ship strike’ injuries, likely the result of their large numbers in the area, rather than high levels of ship strikes. Only one possible ship-struck humpback whale was recorded, despite concentrations of humpbacks feeding within shipping lanes in this region. This study shows dramatic differences in occurrences of ship-struck large whales by species, which we believe results from a combination of species' vulnerability to ship strikes, and how likely a struck whale is to be caught up on the bow of a ship and brought to waters where it can be examined.

Leptogorgia christiae is a rarely collected new species found at 15–30 m depth at Roca Hacha, a rocky outcrop near Coiba Island characterized by its high diversity of octocorals. The branching pattern and combination of asymmetric blunt spindles, abundance of capstans, and a low occurrence of acute spindles are distinct characteristics of the new taxon. The new species is described, illustrated and compared to the other species of the genus reported from Pacific Panama; thus increasing the total of Leptogorgia species to 17, which encompasses over 70% of the shallow water species for the eastern Pacific.

‘Phalanx’ and ‘guerrilla’ phenotypes have been characterized as distinct, adaptive growth strategies exhibited by marine encrusting taxa, as well as a variety of other colonial taxa, that differ in patterns of colonial growth and areal expansion. Phalanx morphs exhibit compact growth, expanding outward concentrically and generating radially symmetric colony shapes, whereas guerrillas exhibit diffuse growth and typically elongate, asymmetric colony shapes. Several species in the colonial hydroid genus Hydractinia display inter-genotypic morphological variation in early developmental growth, although it is unclear if and how this growth form variation is tied to colony symmetry. Here I show that the phalanx versus guerrilla distinction does not adequately characterize genetic variation in Hydractinia growth form. Genotypes characterized by extreme mat and stoloniferous growth exhibited high levels of symmetry while genotypes generating growth forms intermediate between these two extremes were more asymmetric. Asymmetric growth is tied to reduced field fitness as a result of slower growth, reduced investment in future reproduction, and increased susceptibility to abiotic environmental stress. Asymmetric, guerrilla-like growth may be the morphological symptom of maladaptive growth early in colony development. This notion contrasts greatly with the traditional view of guerrilla growth as an adaptive strategy. Several hypotheses are proposed to address why asymmetric, guerrilla-like growth may be maladaptive in this and similar systems.

Meiofauna assemblages were investigated at 15 stations on triplicated samples in the Uvea Atoll (Loyalty Islands) in relation to 9 selected environmental parameters. Spatial patterns and variability of meiofauna density were quantified according to location, macrofauna and nematode species assemblages. Meiofauna was dominated by ciliates and nematodes. Densities of total meiofauna and of most of the meiofauna taxa were significantly higher in the back reef North Pléiades stations than the leeward side of the Island. The highest correlation between biotic patterns and environmental parameters that best explains the pattern was with sediment thickness and to a lesser extent organic matter, C/N ratio and depth. One hundred and thirty-four nematode species were identified with four dominant species Chromadora macrolaimoides, an undescribed species of Bolbonema, Daptonema svalbardense and Prochromadorella septempapillata. Three significantly different nematode species assemblages were detected in two of the previously described macrofauna assemblages by cluster analysis and multidimensional scaling methods suggesting that nematodes are more sensible ecological indicators than macrofauna. Diversity indices based on dominance were not significantly different among the three nematode species assemblages but indices based on species richness and rarefaction were significantly higher leeward of Uvea Island. Estimates of total species richness showed no sign of stabilizing with sample size. However, rare species stabilized very quickly, whereas abundant species were added with increasing sampling coverage, indicating a high spatial variability of the local composition of nematodes.

The sexuality of large (non-dwarf) individuals and the characteristics of eggs, larvae and dwarf males were investigated in the pedunculate barnacle Scalpellum stearnsii. All 103 large individuals collected in this study were not hermaphrodites but females. The major length axis of the egg was on average 0.50 mm, which was larger than that in most thoracican barnacles with planktotrophic larvae. The larvae hatched as nauplii and metamorphosed into cyprids without feeding (i.e. lecithotrophic development). There was a positive relationship between body weight and egg mass weight in ovigerous females. The number of males attached per female ranged from 0 to 35 (average: 5.9) and there was a positive relationship between the number of males and female body weight. The distribution of dwarf males was skewed significantly towards the lower part of the occludent margin, which is near the fertilization site.

Manatee mortality in Ceará State (north-eastern Brazil) is analysed from twenty-five strandings between 1987 and 2002. The majority of the causes were related to the ‘dependent calf’ category (83.3%). Direct human-related causes were attributed to incidental catches in fishing gear (shrimp trawling and gill-nets) (12.5%) and direct capture (4.2%). Spatial distribution was not uniform, with the highest number of strandings on the east coast. The number of strandings has increased since 1999, and the seasonal distribution showed peaks in February, March and January, in that order. The stranding of manatee calves in Ceará State seems to be indirectly related to human activities that impact coastal nursing habitats.

In a series of studies on eunicids, there were explicit or implicit indications that Eunice riojai described from the north-western Caribbean Sea, and Eunice sebastiani described from south-east Brazil, were synonyms. This was based upon a then recent monograph on the genus, and on the fact that some specimens were found in drifting wood which would explain the large geographical range. The study of some large specimens of E. sebastiani, collected at the type locality, shows that there are several relevant morphological differences between the two species and thus both species names must be regarded as distinct. In fact, E. sebastiani is unique in the genus because their maxillae V are bidentate. Furthermore, herein we re-describe these two species and re-evaluate some morphological features described in previous studies.

Previous observations in the St Lawrence Estuary (eastern Canada) suggested that larvae of intertidal barnacles (Semibalanus balanoides) would settle almost exclusively inside crevices on shores that are scoured by sea ice every winter. It was suggested that the strong ice scour in winter on that coast (which removes organisms outside of crevices) would select for such a larval behaviour. We tested the generality of this pattern by sampling other ice-scoured shores within the Gulf of St Lawrence system. In particular, we surveyed a shore in Nova Scotia where exposed habitats (subjected to strong ice scour in winter) are interspersed with sheltered habitats (which suffer milder ice scour). Such a topographical complexity might allow for the coastal larval pool to contain a proportion of larvae that have no particular settlement preference for crevices, as selective pressures for such a behaviour would be minimal in ice-sheltered habitats. Consistently with this notion, barnacle recruits (which appear after the winter ice melts) occurred abundantly both inside and outside of crevices across the shore in the spring seasons of 2005 and 2006. Average recruit density on rocky surfaces ranged between 337 and 588 recruits dm−2, depending on the habitat. It is therefore possible that barnacle recruitment patterns on ice-scoured shores may be affected indirectly by the structural complexity of the coast.

The family Monhysteridae is characterized by 17 valid genera, seven of which are known to be free-living, inhabiting marine sediments. In total, 70 valid marine species are ascribed to these seven genera. Overall, the family is characterized by a confused taxonomic history with a large list of synonyms and species inquirendae. The taxonomic problem is not restricted to the old literature, but inconsistencies also appeared in recent studies. The aim of this study is to show the most important diagnostic characters to identify each genus and provide taxonomic tools for species identification. Dichotomous-keys and illustration-guides are attempted for the marine monhysterid species. For the family and each subfamily, tribe and marine genus a brief historical background, diagnosis and a list of valid species is provided. Hereby, we propose to transfer eight species of the genus Thalassomonhystera to the genus Monhystrella.

Landmark-based geometric morphometric methods were used to test which chela is most suitable to use in population differentiation of brachyuran crabs. Two species were analysed: Pachygrapsus marmoratus, a homochelous species, and Carcinus maenas, a heterochelous species. Variance analysis of shape variables and of each chela was calculated to determine which claw presents less variation within populations. The results showed that the right chela of P. marmoratus is more appropriate to use when the goal is to differentiate populations. In C. maenas, the males major chela and females right chela are more suitable to use, probably due to its heterochely. To test these results, specimens from different geographical locations were compared. Pachygrapsus marmoratus populations presented significant differences in manus shape, and C. maenas populations had differences in polex size and shape. Differences in carapace shape were also encountered between populations of both species. This phenotypic variation was not corroborated with genetic data, which were obtained using the mitochondrial DNA gene cytochrome oxidase I as a marker. These opposite results suggest that environmental factors, such as diet and parasitism, can be determining shape differentiation.

Ceratothoa collaris is reported for the first time outside its known geographical range, which was restricted to north-western African coasts (from Senegal to Tunisia). Many specimens of different developmental stages were collected off the Lebanese coast in the eastern Mediterranean. In addition to an update of the geographical range, synonymy and host specificity, an accurate redescription of the species is given on the basis of new and old materials.

This one-year study investigated spatial and temporal variations in the abundance and biomass of the pink shrimp species, Farfantepenaeus paulensis and Farfantepenaeus brasiliensis, in the Conceição Lagoon, southern Brazil (September 2003–August 2004). The influence of salinity, water temperature, and rainfall on shrimp distribution was evaluated. Shrimps were caught monthly at three areas within the Conceição Lagoon (Canto, CA; Centro, CE; and Costa, CO). A total of 744 shrimps were sampled, with F. brasiliensis being the dominant species. The two penaeid species were present throughout the year and significant differences were observed between seasons, with F. paulensis being more abundant during the summer and F. brasiliensis in the autumn, suggesting differential migration timing to the sea, differences in recruitment time and an ontogenetic temporal partitioning. Farfantepenaeus paulensis exhibited a homogeneous spatial distribution, whereas F. brasiliensis was more abundant in CE and CO, suggesting that habitats in this coastal lagoon are heterogeneous. Among the abiotic factors, temperature and salinity seemed to be important variables in defining seasonal and spatial patterns, respectively, of the abundance of F. brasiliensis.

A massive attack of caprellids is reported here, that is related to a local mortality event of gorgonians in North Sulawesi. Three species of sea fans were affected by the presence of Metaprotella sandalensis, a caprellid widely distributed in the Indo-Pacific. The degree of damage here documented was in relation to the skeletal features of the gorgonian species. The amphipod gut contents were analysed, highlighting an unusual trophic source for caprellids and a new predator for gorgonians. This phenomenon is discussed also evidencing parallels between colonial marine invertebrates and their predators and terrestrial plant–herbivore interactions.

The hydroid assemblage of the Siladen Island coral reef (North Sulawesi, Indonesia) is made up of 107 species belonging to 51 genera and 28 families. The study of their spatial distribution has identified three different zones which are well-characterized: (1) the reef flat, where hydroids are mainly represented by cryptic species living in the shady crevices of the corals, epibiontic on sponges or sea grasses; (2) the edge of the reef characterized by hydroids growing mainly on the shady side of the corals, with the exception of the tufts of the large colonies of the stinging zooxanthellate Aglaophenia cupressina; and (3) the vertical reef, where hydroids reach their maximum diversity and abundance and are often involved in symbiotic relationships.

The number of hydroid species shows a seasonal trend with a summer minimum (July–September) and a winter maximum (November–February). The strong correlation between these variations and the abundance of rainfall suggests that food availability, strictly related to the seasonal amount of rain, represents the main abiotic factor triggering the hydroid species richness and the abundance of this tropical assemblage.

Measuring the impact of anthropogenic factors on marine mammals is critical to the conservation of these species. Recently, the effect of personal watercraft on marine mammal behaviour and well-being has become a topic of increasing concern. The purpose of this study was to examine the immediate effects of high-speed personal watercraft on Atlantic bottlenose dolphin (Tursiops truncatus) behaviour. Opportunistic surveys were conducted from a research vessel in the Mississippi Sound (30º13′22.6″N 89º01′36.5″W) from September 2003 through to August 2005. The passing of a high-speed personal watercraft significantly increased dolphin dive duration, dolphin group cohesion and dolphin breathing synchrony. Additionally, in 47% of the encounters a dolphin group's behaviour changed within one minute of the presence of a high-speed personal watercraft. The most notable changes were an increase in dolphin travelling behaviour and a decrease in feeding behaviour following the boat's presence. The results demonstrated an immediate, short-term change in dolphin behaviour, suggesting that an increase in the frequency of high-speed personal watercraft in this area could produce long-term detrimental effects. Research on the long-term effects of boat traffic on marine mammals is clearly needed to assess and hopefully mediate any potential long-term effects.

Amphinomida is an ‘isolated’ clade within the polychaete group Aciculata and traditionally includes the families Amphinomidae, Archinomidae and Euphrosinidae. Archinomidae were erected for a single species, the hydrothermal vent polychaete Archinome rosacea. Originally, A. rosacea was assigned to Euphrosinidae although it shares more morphological similarities with Amphinomidae. In this study we assess the position of Archinome, Euphrosinidae and Amphinomidae by using molecular data from nuclear 18S rDNA and 28S rDNA. Parsimony, maximum likelihood and Bayesian analyses are performed on the nucleotide datasets covering in total 19 terminals from Amphinomidae, Euphrosinidae, Archinomidae and outgroups. Our results conclusively show that Euphrosinidae and Amphinomidae are sister taxa and that Archinome is sister to Chloeia within Amphinomidae. Based on these results the family name Archinomidae is treated as a junior synonym of Amphinomidae.

In a study investigating the composition and spatial and temporal variation of the benthic macrofauna associated to the discharge of domestic sewage off Fortaleza, north-eastern Brazil, a new species of Syllis was found. This new species, S. guidae sp. nov., is characterized by having blades of falcigers with subdistal tooth about same length as distal tooth, but stouter than it, with spines on cutting edge almost reaching the tip of subdistal tooth, blades of falcigers with conspicuous subdistal triangular process and unusually long anal papilla between anal cirri, measuring about one-quarter of their length. Syllis guidae sp. nov., is herein described and compared with the most similar congeners.