Long-term population dynamics of three-spined stickleback Gasterosteus aculeatus in the White Sea during the 20th century has patterns similar to that of eelgrass Zostera marina. In this study we address possible mechanisms of such association through analysis of spatial distribution of juvenile stickleback in the wild and their substrate preferences in experimental conditions. Samples from different habitats (Z. marina, Fucus spp.) in 13 localities of Kandalaksha Bay have shown that the juvenile sticklebacks occurred mainly in the eelgrass beds. Their density was significantly lower in fucoids. In the experiments, carried out in August 2008–2009, the juveniles were offered the following types of substrates: brown macroalgae (dense and scarce), eelgrass and control (no substrate). In the experiments sticklebacks also showed a tendency to prefer eelgrass to fucoids, even if the density of the latter was higher. This may explain their higher densities associated with eelgrass in the wild.

Paramya is an enigmatic genus of Myidae (Bivalvia: Heterodonta: Myoidea) that includes three uncommon species: Paramya subovata (Conrad, 1845), Paramya recluzi (A. Adams, 1864) and Paramya africana Cosel, 1995. Paramya subovata is known as a commensal living in the burrow of the spoon worm Thalassema hartmani Fisher, 1947 (Annelida: Echiura: Thalassematidae), in North American coastal waters. However, the biology of the other two species remains unknown. In this study, we found P. recluzi living in the burrows of the two thalassematid echiuran species, Ikedosoma gogoshimense (Ikeda, 1904) and Arhynchite hayaoi Tanaka & Nishikawa, 2013, in intertidal flats in the Seto Inland Sea, Japan. Paramya recluzi was embedded in the burrow wall with its short siphons protruding into the host burrow lumen for respiration and filter feeding. To determine the phylogenetic position of P. recluzi, we performed a molecular phylogenetic analysis using the 18S, 28S, COI and H3 genes. Molecular analysis showed that P. recluzi belongs not to the family Myidae, but to the genus Basterotia (Galeommatoidea: Basterotiidae). Morphological examination of P. recluzi revealed that this species has many similarities with Basterotia (e.g. a single cardinal tooth on each valve and short siphons surrounded by tentacles). Thus, we propose that this species should be transferred from the genus Paramya to Basterotia. In addition, we also suggest that the other two species of Paramya (P. subovata and P. africana) should be transferred to the family Basterotiidae based on their shell morphology, anatomy and ecological characteristics.

An area in the central North Sea was surveyed in November 2011 in order to estimate the abundance and density of harbour porpoises (Phocoena phocoena). A total of 2833 km of pre-determined trackline were acoustically surveyed, of which 28% included visual effort. The poor sighting conditions during the survey limited visual effort and demonstrated the advantage of using acoustic techniques for studying harbour porpoise in winter months. Absolute abundance and density estimates were calculated from acoustic encounter rates using estimates of probability of detection and mean group size. The density of harbour porpoises in the west of the survey area was almost double that in the east, with UK waters to the south-west of the Dogger Bank having the highest density of the area surveyed. The overall acoustic encounter rate was higher than most other surveys in the North Sea. The mean density across the survey area of 0.63 (95% CI 0.27–1.52) individuals km−2 and distribution of porpoises was similar to that documented in the summer suggesting that high abundance of harbour porpoises in the west of the North Sea is not confined to summer months. This information is particularly relevant given plans for the construction of a large offshore wind farm on the UK section of the Dogger Bank; the resulting impacts, including acoustic disturbance from pile driving, will potentially affect substantial numbers of harbour porpoises.

Winter cooling and persistent mixing for more than a quarter of year (November to early March) along the North Eastern Arabian Sea (NEAS) results in nutrient enrichment of the euphotic column thereby triggering biological production. Hydrographic characteristics of NEAS during Late Winter Monsoon (LWM) and Early Spring Inter Monsoon (ESIM) and the influence on biological production are overviewed here. Winter convective mixing signatures were evident during LWM with low SST (24°C), high SSS (36.4), deep mixed layers (>100 m) and increased surface nitrate (~1 µM). Open ocean waters observed high chlorophyll a (1–2 mg m−3) and microphytoplankton abundance (1.2–1.5 × 104 cells l−1). Diatoms and green Noctiluca scintillans were the major microphytoplankton identified. ESIM observed gradual stabilization of water column with curtailment of winter signatures and strengthening of Noctiluca scintillans blooms. Mesozooplankton biomass was higher during LWM and decreased towards ESIM with intensification of Noctiluca blooms. However during ESIM, abundance of gelatinous zooplankton occurred in the bloom region. Inter-annual variations were observed in the biological responses along with the hydrographic changes. Thus the convective process during winter monsoon and stabilization of the water column during ESIM plays a significant role in the production pattern of NEAS.

Accurate discrimination of two morphologically similar species of Patella limpets has been facilitated by using qPCR amplification of species-specific mitochondrial genomic regions. Cost-effective and non-destructive sampling is achieved using a mucus swab and simple sample lysis and dilution to create a PCR template. Results show 100% concurrence with dissection and microscopic analysis, and the technique has been employed successfully in field studies. The use of highly sensitive DNA barcoding techniques such as this hold great potential for improving previously challenging field assessments of species abundance.

Spatial and temporal variability and bloom formation of the potentially toxic diatom Pseudo-nitzschia spp. was investigated weekly to monthly from October 2009 to October 2010 in a eutrophic estuary, the Golden Horn. Pseudo-nitzschia spp. were detected in 195 of 512 samples (38%) collected throughout the year. Two species, P. calliantha and P. pungens, were identified based on the SEM examination. Blooms of Pseudo-nitzschia occurred in the lower and middle estuary in January and May. The bloom in January mainly comprised P. calliantha. In the bloom in early May, P. calliantha made up 72% of the Pseudo-nitzschia cells and P. pungens 28%. However, the contribution of P. pungens increased to 83% in late May. The Pseudo-nitzschia blooms occurred at low temperature (9–15°C) and moderate salinity (17–18), and for P. calliantha a significant negative correlation was found with temperature and a significant positive correlation with salinity. The percentage of Pseudo-nitzschia cells decreased gradually from lower to upper estuary (59–14%), correlating with a decrease in Secchi depth (5.5–0.5 m). Principal components analyses (PCA) were used to explore the spatial and temporal variability of environmental factors in relation to Pseudo-nitzschia abundances, and showed that NH4, pH, Secchi depth and DO values were the most important factors reflecting spatial differences, while temperature, salinity, Chl-a and Si:N were more important factors showing temporal differences. High abundances of P. pungens correlated mainly with pH, Secchi depth and DO values, whereas P. calliantha also correlated with NO3 + NO2. Low light availability due to high concentrations of suspended material and very variable environmental conditions (e.g. pH, DO and NH4) may have limited growth of Pseudo-nitzschia in the upper estuary. Regular monitoring of Pseudo-nitzschia is important for improving the understanding of the influence of environmental parameters on bloom dynamics in the study area.

The imposition of male sexual characteristics onto the female (imposex) is present in wild populations of the non-native veined rapa whelk (Rapana venosa) in Chesapeake Bay, USA but does not appear to compromise reproductive function. Cultured whelks were used to test two hypotheses: (1) Observed imposex metrics will be similar to tributyltin (TBT) water concentrations at each of three sites; (2) Male and imposex/female whelks from the same site will have similar TBT body burdens. Cultured 2-year-old whelks were transplanted to three field sites in the York River, USA at the onset of their second reproductive season. Transplant site mean TBT water concentrations ranged from 1.4 ± 0.77 to 64.2 ± 57.8 ng l−1. Imposex incidence was 100% after 28 weeks with an observed M:F:IF ratio of 81:0:92 across all sites. Imposex stages (median vas deferens scale index = 4) and reproductive output were similar across sites. The imposex severity (IS = penis length/shell length) increased with increasing TBT concentrations. The relative penis length (RPLI) and relative penis size (RPSI) indices were positively related to site-specific TBT levels. Male whelks accumulated significantly higher TBT concentrations than female whelks at the site with the highest TBT concentration. Mean TBT concentrations in whelk egg capsules were significantly higher than concentrations in male or female whelk tissue. Egg capsule deposition provides a depuration mechanism for female whelks to reduce body burden of lipophilic TBT. Sex, season and reproductive status should be considered when using gastropod bioaccumulation to monitor TBT effects.

Stomach content analysis was used to assess the feeding habits of Acanthocybium solandri based on samples obtained on purse seine fishing trips off the Pacific coasts of Central and South America. A total of 226 samples were obtained; 160 stomachs contained food and 33 prey taxa were identified. Based on the Prey Specific Index of Relative Importance (%PSIRI), cephalopods and fishes were the main prey groups (50.4 and 49.5% PSIRI). Dosidicus gigas (23.4% PSIRI), Stenoteuthis oualaniensis (9.9% PSIRI) and Argonauta spp. (9.4% PSIRI) were the most representative prey. Acanthocybium solandri is a generalist predator based on the results of the Amundsen analysis and niche breadth (Ba = 1).

Swordfish (Xiphias gladius) is heavily exploited in the Atlantic Ocean by several European fleets and age and growth studies are essential for the accomplishment of the stock assessments carried out by ICCAT. The present study aims to validate the periodicity of growth increments on swordfish fin spines and provide first estimates of the growth parameters of South Atlantic swordfish. A total of 502 (231 males and 271 females) spine samples were collected from swordfish specimens onboard commercial longline vessels, from 2006 to 2009. Estimated ages ranged between 0 and 12 years, with age groups 3 and 4 dominating the samples. Marginal increment analysis suggested that growth bands were deposited annually in mid-spring. Fitted standard von Bertalanffy growth parameters (sexes combined) were L∞ = 317.133, k = 0.085 and t0 = −2.488. Minor, but insignificant, growth differences were observed between sexes.

This study tested for social monogamy in Alpheus brasileiro Anker, 2012. We also analysed egg production in this species. Sampling was conducted bimonthly from March 2013 to January 2014, and specimens were collected manually in the intertidal estuarine zone of Cananéia, São Paulo, Brazil. A total of 186 specimens (92 males and 94 females) were captured, and ~46% of them were found living in heterosexual pairs. The carapace length (CL mm) of paired males and females was positively correlated. We analysed 35 females carrying eggs underneath the abdomen: 28 of these females had eggs in stage I of development, four had eggs in stage II, and three had eggs in stage III. The average (±SD) mean fecundity for females carrying early (stage I) eggs was 149 (±93) eggs. Egg volume differed significantly among developmental stages, with a 35.4% increase in egg volume between stages I and III. The egg volume and size (CL) of females correlated positively. A positive correlation between the number of eggs and carapace length was found, with a proportional increase in the number of eggs according to the size of females. Our results suggest that the studied population of A. brasileiro is socially monogamous and provide the first insights into egg production in this species.

The taxonomy of Mediterranean populations of Diodora is assessed based on new molecular (COI and 28S) data. The recently described Diodora demartiniorum Buzzurro & Russo, 2005, is found to be a valid species restricted to the Gulf of Gabès (Tunisia) but possibly occurring also on the coast of Libya. However, specimens from the Aegean Sea previously identified as D. demartiniorum are molecularly (and morphologically pseudocryptically) distinct and represent a previously unrecognized species here described as D. giannispadai n. sp. It is hypothesized that the current distribution of these two species corresponds to glacial refuges during Pleistocene climate changes.

The infauna of Chabahar Bay (Iranian Coast of the Gulf of Oman) was investigated using shallow water (less than 10 m) grab-samples between June 2013 and March 2014. The magelonid fauna of these samples was studied and prioritized, with four species being present: M. fauchaldi sp. nov., M. symmetrica, M. cf. cincta and M. crenulifrons. The new species differs from all known magelonid species within the Persian Gulf region in possessing polydentate abdominal hooks. A fifth species, currently undescribed, was also found. The validity of M. pulchella originally described from Kuwait is discussed in light of its closeness to M. crenulifrons. The main distinguishing feature between the two species is the presence or absence of crenulation of the anterior prostomial margin, a character shown to be variable in M. crenulifrons. Although differences between the type specimens of both species suggests M. pulchella to be a valid species, examination of further material and DNA analysis is needed.

During quantitative surveys two new species of Cirratulidae from subtidal bottoms of the Atlantic coast of Argentina were collected. They belong to the genera Monticellina and Chaetozone. Monticellina morae sp. nov. is characterized by the presence of a long peristomium of smooth appearance, but triannulated at SEM, bearing the dorsal tentacles in the posterior part, with the first pair of branchiae posterolateral to the dorsal tentacles in chaetiger 1. The body is divided into three parts, an anterior region laterally expanded and with crowded segments, a middle region with beadlike chaetigers and an inflated and crowded posterior region. Chaetozone larae sp. nov. is characterized by an inflated dorsally and laterally expanded anterior crowded region. Peristomium biannulated laterally, with a dorsal crest on the first and second annuli that occupy the entire width, and then a narrow crest in the following annulus (interpreted as an achaetous segment). Capillaries are lanceolate, short and long, with acicular spines curved, forming partial cinctures. In addition, a comparative table of all described species of Monticellina is included and the distinctive characters are discussed.