Terebellomorph polychaetes are reported from hydrothermal vents and cold seeps collected in the Pacific and Atlantic Oceans. Two new species of Terebellidae, Neoamphitrite hydrothermalis sp. nov. and Streblosoma kaia sp. nov., are described from hydrothermal vents of the western Pacific. These are the first terebellid species described from hydrothermal vents. New records from hydrothermal vents and cold seeps and new geographical records are presented for nine additional species belonging to Ampharetidae, Alvinellidae, Terebellidae and Trichobranchidae. A synoptic table with diagnostic characters for all species of the genus Streblosoma Sars, 1872 is provided. Keys for all terebellomorph species currently known from hydrothermal vents and cold seeps, respectively, are included. Additionally the new combination Neoamphitrite pachyderma (Hutchings & Glasby, 1988) comb. nov. is proposed.

In order to determine the changes in the relative importance of different kinds of preys as larval anchoveta Engralis ringens grows, the present study reports information about feeding incidence, type, size, and carbon content estimates of preys, at the beginning of the main spawning season in mid-winter off central Chile. Our results show a mixed diet initially dominated by phytoplankton and later switching to zooplankton in older larvae. While larval anchoveta grows, they feed on preys whose widths do not vary much compared to their body length and volume. These preys might be different taxa or a single species whose body widths vary little among life stages (i.e. nauplii and copepodites). Differences in estimated carbon content were observed among food items and a marked increase in carbon consumption was observed in the larger larval sizes (>9 mm standard length). These ontogenetic changes in feeding are coincident with the increased proportion of larger preys and also with the number of preys consumed by larger larvae.

Specimens of twaite shad, Alosa fallax were sampled from commercial purse seiners and trammel netters in Izmir Bay during November and December 2007. A total of 287 prey items from 14 taxa from 208 stomachs were recorded. The primary food of twaite shad was found to be fish, especially anchovy Engraulis encrasicolus, which was the most frequent (%F = 66.11) and abundant (%N = 63.64) prey item, and also had the highest percentage by weight (%W = 81.91). Decapoda, Isopoda, Ostracoda and Copepoda (Calanus spp., Candocia armata, Temora stylifera from Calanoida and Corycaeus spp. from Cyclopodia), were recorded occasionally with low values for all indices. The study showed that in the Aegean Sea Alosa fallax is a predator of small pelagic fish, E. encrasicolus, A. boyeri, S. pilchardus, and some crustaceans. Benthopelagic P. acarne and demersal S. hepatus were first recorded in diet of twaite shad.

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 aim of this study was to analyse the genetic diversity and population structure in the razor clam Ensis siliqua along the European Atlantic coast taking into account their recent history of exploitation and the ‘Prestige' oil spill. To this end we examined the genetic variability of microsatellite markers in 211 razor clams from five populations in Ireland, Portugal and Spain. Microsatellite data revealed a low genetic differentiation between the Spanish and Portuguese populations (FST = 0–0.032) and a moderate differentiation of these populations and the Irish samples (FST = 0.071–0.100). Although we observed changes in genetic diversity in accordance with the level of exploitation and the distribution of the oil spill, these changes were mild and not significant after Bonferroni correction. This could be the result of a genuine low impact, lack of statistical power and/or the capacity of this species to recolonize quickly after the impact of anthropogenic stressors. Supporting the latter argument we found a significant temporal heterogeneity of allelic frequencies in samples coming from the same sampling locality that could be attributed to the movement of adults or larvae from unaffected source populations.

Charybdis hellerii is one of several poorly known non-indigenous crabs in the Caribbean. In this study we report on the reproductive dynamic of a shallow subtidal population that invaded Isla Margarita, Venezuela, south-eastern Caribbean Sea > 15 years ago and has persisted in the region up to date. Male and female crabs, both large and small, were found year-round at the study site. The size–frequency distribution indicated a lifespan of 2–3 years. Charybdis hellerii reproduces continuously but with very low intensity during the year. Small individuals (<25 mm carapace length) were uncommon and intermittently found during the study period. Sex-ratio varied between 0.1 and 0.65 (mean ± SD = of 0.46 ± 0.14) and did not differ significantly from 1:1 ratio during most of the year. The size of the smallest brooding female was 36.81 mm carapace width (CW). Behavioural size at first maturity (movable abdomen) in males and females was estimated to be 22.39 mm CW (confidence limits: 18.35–24.72) and 37.43 mm CW (35.55–39.09), respectively. Reproductive output, estimated as the ratio of embryo to female body dry mass, varied between 0.052 and 0.084 (0.07 ± 0.008). Also, reproductive output was size-dependent with large females allocating proportionally less resources to egg production than small females. The reproductive schedule here reported for C. hellerii disagrees with the generalized idea of exotic populations ‘thriving’ in an environment free of natural enemies (e.g. predators, competitors and diseases).

Cetacean species and their habitats are under threat and effective marine management mitigation strategies require knowledge and understanding of cetacean ecology. This requires data that are challenging and expensive to obtain; incidental sightings/strandings data are potential underused resources. In this study, incidental cetacean sightings (N = 6631) and strandings (N = 1856) in coastal waters of Cornwall, south-west Britain (1991 to 2008) were analysed for evidence of spatial and temporal patterns or trends. Eighteen species were recorded sighted and/or stranded; key species were identified as bottlenose dolphin (Tursiops truncatus), harbour porpoise (Phocoena phocoena), common dolphin (Delphinus delphis), Risso's dolphin (Grampus griseus) and minke whale (Balaenoptera acutorostrata). There were significant decreases in bottlenose dolphin sightings and pod size but an increase in harbour porpoise and minke whale sightings. Cetacean strandings showed a recent decrease over time although there was a significant positive trend in harbour porpoise strandings that correlated with sightings. Incidence of sightings and strandings were both greater on the south coast than the north coast. When Marine Tour Operator data were analysed, distinct species-specific inshore and offshore habitat use was evident. With rigorous interrogation and editing, significant patterns and trends were gained from incidentally collected data, highlighting the importance of public engagement with such recording schemes and the potential of these underused resources.

Parasitism is increasingly recognized as an important determinant of population dynamics, productivity and community structure in intertidal ecosystems, and yet there is very little known about the effect of parasites on polychaetes, which represent a major component of the benthic fauna. We surveyed 11 polychaete species from a mudflat in Otago Harbour, New Zealand, and found that seven of these were infected by five parasite species: four trematodes and one apicomplexan gregarine. The gregarine found in Spirobranchus cariniferus and a strigeid trematode using Streblosoma toddae as its first intermediate host are both likely to have negative fitness impacts on their hosts. Other trematodes found were at the metacercarial stage and thus use polychaetes as second intermediate hosts. The most common, an opecoelid, infected the polychaetes Heteromastus filiformis and Abarenicola affinis at relatively high abundance. There was no indication of parasite-induced mortality in these two hosts based on the relationship between host size and infection intensity. However, a comparison of intact H. filiformis individuals with those that fragmented during collection revealed a significantly higher number of opecoelid metacercariae per segment in the fragments than in the complete individuals, suggesting that infection may compromise the structural integrity of the polychaetes. These results suggest that there exists a great diversity of both trematodes and host–trematode associations within the polychaete fauna, whose ecological impact remains to be quantified.

A male specimen of Tripedalia cystophora (Cubozoa: Tripedaliidae) was collected from Lake Wyman, Boca Raton, Florida, USA. This is the first report of this species from the continental United States and brings the total known number of cubozoan species living in this region to four. Lake Wyman is a natural lagoon/estuary ecosystem which is part of the Atlantic Intracoastal Waterway. The box jellyfish was found in shallow water around the roots of the red mangrove, Rhizophora mangle, where it was observed feeding on copepods attracted to light. This finding may indicate a local population in the waters of south Florida, USA, but an isolated occurrence cannot be ruled out.

Habitat use of Manta alfredi and M. birostris was assessed at 20 localities in the Indian and Pacific Oceans based upon 3328 photographic observations. Geographical relationships of the two species were scored as either microallopatry, microparapatry or microsympatry at each locality. Our study revealed a mosaic habitat occupancy by the two species within their macrosympatric range.

Three new species of free-living marine nematodes Micoletzkyia longispicula sp. nov., Micoletzkyia filicaudata sp. nov. and Micoletzkyia nanhaiensis sp. nov. from the Yellow Sea and the South China Sea are described. Micoletzkyia longispicula sp. nov. is characterized by spicules elongated and straight, 7 a.b.d. long, pear-shaped proximally and pointed distally; gubernaculum conical, without apophysis, and tubular supplement headlike proximally. Micoletzkyia filicaudata sp. nov. is characterized by slender body with relatively long filiform tail (8.1 a.b.d.), spicules elongated and straight (4.4 a.b.d.), cephalate proximally and pointed distally, gubernaculum tubular, with dorsal apophysis. Micoletzkyia nanhaiensis sp. nov. is characterized by spicules slender and curved, 2.5 a.b.d. long, cephalous proximally and chapiter-shaped distally, and gubernaculum with relatively long dorsal apophysis. A key for all known species of Micoletzkyia is proposed.

The present paper is the first annotated account listing all species of Cirripedia: Thoracica recorded from the Canary Islands (eastern Atlantic Ocean) together with notes on their distribution and ecology. Voucher specimens have been deposited as reference material in the collection of the Instituto Canario de Ciencias Marinas. Seventeen species are listed and seven of them are recorded for the first time for the Canaries: Lepas hilli, Conchoderma virgatum, Xenobalanus globicipitis, Chthamalus sp. (cf. C. proteus), Acasta cyathus, Balanus trigonus and Perforatus perforatus.

The sexual system of two caridean shrimps (Processa riveroi and P. bermudensis) was investigated, stimulated by reports of male to female sex change (protandry) in Processa edulis from European waters. Shrimps used in the study were obtained from monthly samples taken from March 1982 to February 1983 in a Thalassia–Syringodium seagrass meadow in Puerto Rico. Observations on size, sex, and reproductive condition were used to construct monthly size–frequency distributions and sex-ratios by size-class (SC). Males were smaller than reproductive females, but there was extensive overlap in size between males and immature females. A sex-ratio (SR) analysis by SC of the overall year-long population sample showed an equal or female-biased SR in the smallest SC, a male-biased SR in 1–3 intermediate SC, with larger SC dominated by females incubating embryos. Such a population structure might result from slower growth in males than females and higher mortality in larger males. Observations on and allometric analysis of sexual characters failed to identify transitional individuals (sex-changers) intermediate in reproductive morphology between males and females. Thus, a hypothesis of protandry is rejected, and that of gonochory (separate sexes) is accepted in these two Processa species, revealing possible variation in sexual systems among Processa species.

The stomach contents of 1096 specimens of Chelidonichthys lucerna were examined in order to analyse their diet composition according to fish size, sex, depth and season. Sampling was carried out from May 2005 to March 2007 during several bottom trawl surveys in the Adriatic Sea (north-east Mediterranean). Feeding activity was more intense in juveniles than in adults. The most important prey was Crustacea (mainly Decapoda: Brachyura, such as Goneplax rhomboides, Liocarcinus spp., Philocheras spp.) and Teleostei (mainly European anchovy Engraulis encrasicolus and black goby Gobius niger). There was no difference between male and female diet. Feeding habits varied with size, with fish dominating the stomach contents of larger specimens. Finally, fish increased in winter and crustaceans in summer. Chelidonichthys lucerna shows a generalist and opportunistic foraging behaviour, preying mainly epibenthic and nectobenthic organisms.

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.