Studies of cyanobacterial bloom dynamics show that the highest biomass accumulation of Nodularia spumigena is observed in the shallowest area of the Gulf of Gdańsk in summer. In the same region and time, the highest fish abundance is observed. Mostly young individuals of gobies, small sandeel, flounder, three-spine stickleback and young herring occur. In this work we compare how toxic blooms of cyanobacteria influence the number and structure of fish communities in a coastal zone. The results obtained in our study were rather unexpected. More fish species were caught and the biomass of fish was higher during a bloom than in a month following the sampling (no bloom).

The present study aimed to describe the reproductive cycle and estimate the size at sexual maturity of the Manila clam (Ruditapes philippinarum) in the Tagus Estuary (Portugal). Specimens were collected monthly from September 2013 to December 2015 during fishing surveys using bivalve dredges. The gametogenic cycle was described in detail using gonad histology and monitored throughout the study period by the monthly variation in the frequency of gonad maturation stages, mean gonadal index and mean oocyte diameter. This invasive population of R. philippinarum displayed synchronous gonadal development between sexes, with ripening occurring mainly in April and May followed by an extensive spawning period until November–December. Individuals reached the size at first sexual maturity at 29.4 mm in shell length (i.e. before 1 year old). Furthermore, the reproductive strategy, dynamics and potential were compared between the invasive R. philippinarum and the native congeneric carpet shell clam (Ruditapes decussatus). Overall, the data gathered in this study constitutes valuable baseline information to propose conservation strategies and implement management measures to minimize the harmful impacts caused by this invasive species on local ecosystems and native biodiversity, particularly over populations of autochthonous bivalves.

Nymphonella tapetis (Pycnogonida, Ascorhynchidae) is an endoparasitic sea spider affecting bivalves. Recently, sea spiders have been found on a massive scale in the commercially important Manila clams (Veneridae, Ruditapes philippinarum) in Japan (Tokyo Bay). Simultaneously, mass mortality has occurred in this area. Local fishers assumed that this mass mortality was caused by the parasitic sea spider, despite the effect of the parasite and parasite intensity on the host being unknown. To evaluate the susceptibility of the Manila clam to sea spider infestation and the impact on mortality levels, we established six treatments at different infection intensities (density of newly hatched larvae of sea spiders) over a 6-month long laboratory experiment. We monitored mortality and three susceptibility indices (clearance rate, sand-burrowing speed and adductor muscle strength) under sufficient food conditions. Parasitization by sea spider affected clearance rate and sand-burrowing speed. The pattern of parasitic intensity effects on survival of Manila clam hosts was shown to be dependent on the levels of parasite numbers, i.e. clams with lower parasitic levels (total of <200 hatching larvae of sea spider given to a host) have a higher survival rate, and high mortality of host clams was shown in excessively higher parasitic densities (400–4000 individuals). Such pattern of parasitic effects on host survival might be one of the causes of mass mortality of Manila clams occurring in the field.

The metamorphic responses of mussel (Mytilus coruscus) larvae to pharmacological agents affecting G proteins and the adenylate cyclase/cyclic AMP (AC/cAMP) pathway were examined in the laboratory. The G protein activators guanosine 5′-[β,γ-imido]triphosphate trisodium salt hydrate and guanosine 5′-[γ-thio]triphosphate tetralithium salt only induced larval metamorphosis in continuous exposure assays, and the G protein inhibitor guanosine 5′-[β-thio]diphosphate trilithium salt did not exhibit inducing activity. The non-specific phosphodiesterase inhibitor theophylline and the cAMP-specific phosphodiesterase IV inhibitor 4-(3-Butoxy-4-methoxybenzyl)imidazolidin-2-one exhibited inducing activity, while the non-specific phosphodiesterase inhibitor 3-Isobutyl-1-methylxanthine only showed inducing activity at 10−4 M in continuous exposure assays. The cyclic nucleotide analogue N6,2′-O-Dibutyryladenosine 3′,5′-cyclic monophosphate sodium salt did not exhibit significant inducing activity. Both the adenylate cyclase activator forskolin and the adenylate cyclase inhibitor nitroimidazole exhibited inducing activity at 10−4 to 10−3 M concentrations in continuous exposure assays. Among these tested agents, the adenylate cyclase inhibitor (±)-miconazole nitrate salt showed the most promising inducing effect. The present results indicate that G protein-coupled receptors and signal transduction by AC/cAMP pathway could mediate metamorphosis of larvae in this species.

Edible marine gastropods are consumed in northern Patagonia without regulations or knowledge of nutritional composition and food quality. We determined total lipids (TL), fatty acid (FA), paralytic shellfish poison (PSP) and metal contamination in six edible marine gastropods: Buccinanops globulosus, B. cochlidium, Trophon geversianus, Odontocymbiola magellanica, Tegula patagonica and Nacella magellanica. TL was lowest in the foot (0.29–0.56%) and maximum in organs (1.43–3.2%), presenting less TL than other edible species around the world. Saturated FA were similar to other consumed marine gastropods worldwide and dominant in all species studied (33.26–48.19%), while monounsaturated FA reached about 30% only in 2 species, but did not exceed 18% in the other species. Polyunsaturated FA reached up to 23.77%, but generally did not exceed 14%. Highly unsaturated FA (AA, EPA and DHA), reached about 27%. The dominant FA was palmitic acid (0.217 to 2.43 µg mg−1).Differences in FA could be related to the different alimentation of the species. Limit of PSP consumption was exceeded in a few months only for two species. Lead was not detectable (<4 µg g−1) while cadmium ranged from 0.07 to 15.32 µg g−1. Our results can be useful to ensure the safety food of these resources, which are being consumed and exported in low quantities in Argentina, but may be commercialized massively in the near future. Monitoring these and other food resources is essential and should be performed in any established fishery of the species reported here to guarantee the safety human consumption.

The beach of Porto de Galinhas is socially and economically important because of the reef environment that attracts a large number of tourists. In order to contribute to the monitoring of the environmental quality of the area, which is subject to strong human pressure, phytoplankton composition was analysed in four fixed sampling station, during 4 months of the dry and rainy periods, at high and low tides and at diurnal spring tides. The phytoplankton community structure and the abiotic parameters varied according to seasonality. Phytoplankton biomass ranged from 0.42 to 5.66 mg m−3 and density ranged from 0.50 to 14.3 cell 103 l−1. A total of 192 taxa were identified, belonging to six divisions. The most representative taxa were Ochrophyta (64.6%), followed by Dinophyta (19.3%). Ostreopsis ovata, Trichodesmium erythraeum, Protoperidinium bispinum, Paralia sulcata, Thalassiosira leptopus and Fragilaria capucina were the most representative species of the environment. Ostreopsis ovata was the only highly frequent and dominant species. The Easterly Wave Disturbance contributed to the occurrence of a large number of freshwater species that were observed on the site. The environment was characterized as oligotrophic, tending toward mesotrophic in the rainy season. The high number of taxa associated with high evenness was indicative of environmental balance. Continental interference was perceived due to the variation of abiotic parameters and of the variation of the phytoplankton community structure.

Ninety-six field trips were conducted between summer 2010 and 2012 in order to understand the occurrence and habitat use of Bryde's whale (Balaenoptera edeni) in the Cabo Frio region, South-eastern Brazil. Bryde's whales were present in the study area between November and July, being observed during all seasons, but occur more frequently during the autumn (Nindividuals = 16) and spring (Nindividuals = 13), followed by summer (Nindividuals = 5) and winter (Nindividuals = 2), respectively. Bryde's whales were observed in water depths ranging from 20.1–100 m. Furthermore, during 2240 min of video recordings, the most frequent behaviour observed was foraging (40.2%; 900 min). Travelling comprised 28.1% (630 min) of observations, while in 33.1% (710 min) behaviour could not be determined. Taking into account the pattern of occurrence, the use of deeper bathymetric bins and the frequency observed, the foraging behaviour of Bryde's whales observed in our study seems to be associated to prey dynamics. Our data show that the study area is frequently used for foraging by this species in Brazilian waters.

The invasive sabellid Branchiomma bairdi (McIntosh, 1885) was collected in the Estany des Peix lagoon (Formentera Island, Balearic Sea, Western Mediterranean). This species is native to Bermuda (Western Atlantic Ocean), being widely distributed through the Caribbean Sea. However, it has been described as invasive worldwide, being also present in the Indo-Pacific region, the Eastern Atlantic Ocean and the Mediterranean Sea. We here provide the first record of the species for the Balearic Sea, together with a comparison to other morphologically similar alien species, Branchiomma boholense (Grube, 1878), which is supposed to have also been introduced in the Mediterranean basin. We also include comprehensive taxonomic descriptions of both taxa based on the type material, a dichotomous key for the Mediterranean species of Branchiomma and hypothesize the most likely way of introduction of B. bairdi in the Balearic region.

Some Antarctic littorinoideans have a remarkable convergence with Naticoidea in shell and operculum features. Two naticid-like species of that group are studied in their phenotypic features in order to improve their taxonomy and to discuss the meaning of that convergence, as the former are herbivore-detritivore and the latter active predatory organisms. One of the studied species is the littorinid Laevilacunaria antarctica (Martens, 1885). The other belongs to a new genus – Pseudonatica, with the type species also newly described: P. antarctica, the genus is tentatively placed in Zerotulidae. Another Pseudonatica is also described, P. ampullarica, based only on shells collected by Marion-Dufresne French expedition off Brazilian coast, this finding expands the occurrence of zerotulids northwards. Besides the similarities of shell and operculum, other structures of these Antarctic species also show singular similarities with naticoideans, such as the wide foot, the complexity of opercular attachment in pedal opercular pad, the wide oesophageal gland, and the coiled arrangement of the pallial oviduct. The phenotypic characters were coded and inserted in a previous large phylogenetic analysis on Caenogastropoda (Simone, 2011), furnishing a wide basis for discussion on the characters, taxonomic position, evolution and adaptations of these organisms.

The coast of Brazil is an important low latitude nursery ground for humpback whales (Megaptera novaeangliae). The number of humpback whales in this region has increased and its population is reoccupying areas where it has been depleted during the whaling period. The goal of this study was to conduct land-based observations during 2014 and 2015 to characterize patterns of habitat use and relative abundance of humpback whales that migrate to one of these reoccupation areas: Serra Grande, Bahia state. The observed mean group size was 2.12 ± 0.96 individuals and did not vary through the reproductive season nor between years. Dyads (32.9%) and singletons (26.7%) were more frequently observed, and groups with calves represented 21.2% of the sightings. The mean number of whales counted per hour increased from 2014 (3.44 ± 3.35) to 2015 (5.12 ± 4.18). Habitat use varied during the season; whales used shallower waters closer to shore as the season progressed. The spatial distribution of groups with calves was dependent on the presence and number of escorts. Spatial segregation of groups with calves closer to shore is a key factor in understanding the overall distribution of whales in the area, suggesting that social strategies are affected by environmental factors, as seen in other wintering grounds. Small-scale studies from land-based stations, in areas such as this where there is no previous knowledge about the species, are cost effective. They provide information about the overall behavioural and spatial patterns while anthropogenic activity is still low, allowing habitat protection and management decisions before implementation and increase of human activities.

Polychaetes of 31 species from 17 families (Amphinomidae, Chrysopetalidae, Eunicidae, Glyceridae, Hesionidae, Iphionidae, Lumbrineridae, Maldanidae, Nereididae, Oenonidae, Phyllodocidae, Polynoidae, Sabellidae, Serpulidae, Syllidae, Terebellidae, Trichobranchidae) were studied from five locations around Abu Musa Island, the Persian Gulf. Perinereis iranica sp. nov. is described as a new species for the Persian Gulf. Perinereis iranica sp. nov. is most similar to members of the Perinereis cultrifera species complex, which are also found in the Persian Gulf, but can be most easily distinguished from them by the number, shape and arrangement of paragnaths in Areas V and VI. Perinereis camiguana is compared to members of the genus Pseudonereis, and found to resemble them closely, but until type specimens can be re-examined, we recommend treating this species as Nereidinae incertae sedis. Fifteen species, belonging to 13 genera: Eunice ‘sp_Abu Musa’, Marphysa ‘sp_Abu Musa’, Glycera cf. tesselata, Hesione splendida, Lumbrineris ‘sp_Abu Musa’, Notoproctus ‘sp_Abu Musa’, Nereis sp. cf. N. pelagica, Eteone ‘sp_Abu Musa’, Harmothoe liaoi, Potamilla ‘sp_Abu Musa’, Branchiosyllis cf. exilis, Trypanosyllis ‘sp. 1_Abu Musa’, Trypanosyllis ‘sp. 2_Abu Musa’, Terebella ‘sp_Abu Musa’, Terebellides cf. stroemi are reported for the first time from the Persian Gulf; nine species remain to be named formally. Three genera: Notoproctus, Eteone, Terebella are recorded for the first time from the Persian Gulf.

The sabellariid worms are important ecosystem engineers in coastal zones, due to their ability to construct sand reefs, modify environments and structure biological communities. This article describes the reproductive biology of Sabellaria wilsoni on a beach of the Amazon coast. Each month between May 2008 and April 2009, specimens were collected for morphometric and histological analyses for sexing and determination of gonadal maturity. In females, the number and diameter of the oocytes at different stages of vitellogenesis were also recorded. The results showed that the species is dioecious, with sexual reproduction, females larger than males, and a female-biased sex ratio (overall, 1.6♀: 1♂). Four distinct stages of gonadal maturation were identified in the males and females – (i) initial development, (ii) maturing, (iii) mature and (iv) spawning. Sexual maturity is attained rapidly, and reproduction is continuous, with two breeding peaks, one in the dry season, related to the increased intensity of hydrodynamic conditions and reef erosion; and the other in the rainy season, when the availability of space and nutrients increases. The reproductive strategy of the species reinforces the classification of the sabellariids as r-strategists, adapted to colonize habitats with unstable environmental conditions.

The specific humoral immune response of sea bream, Sparus aurata (L.), against Vibrio anguillarum O1 and Photobacterium damselae subsp. piscicida (Phdp) after immunization with commercial and experimental bacterins was analysed quantitatively and qualitatively. Specific anti-V. anguillarum O1 and anti-Phdp levels provoked by the adjuvanted commercial vaccine reached higher levels in comparison to the aqueous commercial and experimental bacterins. Infection of vaccinated fish with V. anguillarum O1 bacterial cells acted as a boost of the humoral immune response, except for the sera of the group vaccinated with the adjuvanted vaccine. Infection with Phdp acted as a boost of the humoral immune response mainly for the group vaccinated with a monovalent Phdp bacterin and to a lesser degree for the group vaccinated with the aqueous commercial vaccine. Western blot analysis of the sera against V. anguillarum O1 whole cell antigens revealed strong reactions to only a few antigens below 54 kD and above 15 kD and weak reactions to other antigens. Similar reactions were observed from the sera isolated from the controls. Western blot analysis of the sera against Phdp whole cell antigens revealed strong reactions to only a handful of antigens below 20.7 and below 6.4 kD. Sera from the control group, as in the case of V. anguillarum O1, reacted with Phdp whole cell antigens. No differences regarding antigen reactions between monovalent and bivalent formulations were noted, in contrast to the adjuvanted and aqueous bacterins.

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).

The stomach of Decapod crustaceans is a complex structure with great interspecific variation. Several studies suggest that the anatomy of the gastric mill varies according to the diet of species in different groups. An alternative view suggests the gastric mill's structure is related to phylogenetic aspects rather than to the diet of a species. The morphology of the gastric mill of Ovalipes trimaculatus, a portunid crab target of fisheries in Argentina and Chile, was studied through stereo-microscope and scanning electron microscope images. Ovalipes trimaculatus has a stomach that corresponds to a macrophagous and predatory diet. The gastric mill is similar to that of other portunids, especially those with predominant animal component in their diet. Our results support the idea that this structure has a basic pattern, given by shape and elements forming the gastric mill; and upon that pattern, trophic habits adaptively shape certain traits.

Coccolithophores and Parmales are important functional groups of calcified and siliceous marine nanophytoplankton. Large-scale biogeographic distributions of the two groups were investigated based on 71 samples that were collected in the Atlantic Ocean. Using a scanning electron microscope, a total of 48 taxa of coccolithophores and eight taxa of Parmales were recorded, with Emiliania huxleyi, Tetraparma pelagica and Triparma strigata as the predominant forms. The highest abundances of coccolithophores (376 × 103 cells l−1) and Parmales (624 × 103 cells l−1) were observed in waters north-east of the Falkland Islands and the South Georgia Island, in close association with the Subantarctic Front and Polar Front, respectively. Three major biogeographic assemblages, i.e. the Falkland Shelf Assemblage, the Southern Ocean Assemblage and the Atlantic Ocean Assemblage, were revealed in cluster analysis. Additionally, canonical correspondence analysis indicated that temperature significantly affects the latitudinal patterns of the two algal groups. High abundances of Parmales were closely coupled with those of E. huxleyi in waters of the Southern Ocean with low temperature (<10°C). However, the number of coccolithophore species, along with the Shannon–Weaver diversity, significantly increased with elevated temperature, suggesting more diverse assemblages in tropical waters.

Octopus mimus is the main octopus targeted by the small-scale fishery in the Eastern Pacific. Commercial catches of octopus from the Reserva de Producción Faunística Marino-Costera Puntilla de Santa Elena (REMACOPSE) Marine Protected Area in Ecuador were sampled from July to December 2013 in order to describe the reproduction and population structure of this octopus. The 4171 sampled octopuses ranged from 56 to 250 mm in mantle length (ML) and 45 to 3178 g in body weight (BW). Mean octopus weight did not change monthly. Males were mostly mature while the majority of females were immature. Presence of some mature and a few spent females in all months sampled suggests that the population shows an extended spawning period. No spawning peak could be properly defined. Sex ratios did not significantly shift from the expected 1:1 in most samples. Females mature at a larger size (1234 g, BW; 165 mm, ML) than males (487 g BW; 114 mm ML). We recommend considering a minimum legal size of 1200 g BW. A year-long sampling programme for O. mimus should also be completed in order to detect any spawning peak.

Pleuroncodes monodon, an important fishery resource and key species in the Humboldt Current Large Marine ecosystem, has a prolonged reproductive period from winter until end of summer, and during this time females incubating their embryos are exposed to seasonal variation in food availability and in temperature. Additionally, in order to ensure successful reproduction and survival of embryos, changes occur in the main internal reserves and/or sources of energy of P. monodon. The aim of this study was to determine the extent of seasonal variation (winter vs summer) in the lipid content and fatty acid composition of ovigerous females and their embryos. The results show that a higher percentage of saturated and polyunsaturated fatty acids are found in females in winter. Similarly, the composition of fatty acids in embryos found here indicates that winter embryos have more saturated fatty acids and essential fatty acids (C18:2n6cis, C18:3n6 and C22:6n3) than do summer embryos. According to PCA analysis of fatty acid profile, samples from summer may be distinguished into two isolated groups with conspicuous variations in fatty acids profile of embryo and hepatopancreas. While in winter, the opposite pattern occurs in the fatty acid profile of embryo and hepatopancreas. These variations may be related to relevant physiological processes (reproduction and growth) and of their ontogeny (development and survival of offspring). Seasonal variation in the lipid content and composition of fatty acids of P. monodon could directly impact this species’ reproduction and survival and subsequently could have consequences on the food web and fishery exploitation.

Bottlenose dolphins (Tursiops truncatus) are abundant in many coastal ecosystems, including the coastal Everglades. Understanding spatial and temporal variation in their abundance and group sizes is important for estimating their potential ecological importance and predicting how environmental changes (e.g. ecosystem restoration) might impact their populations. From August 2010 to June 2012, we completed a total of 67 belt transects covering a total of 2650 linear km and an area of 1232 km2. Dolphin densities varied spatially and temporally. The highest densities of dolphins were found in coastal oceans and inland bays and were lowest in rivers. Use of rivers, however, increased during the dry season while densities in other habitats remained similar across seasons. Dolphins appeared to prefer portions of bays close to mangrove-covered islands over open waters. A resighting rate of 63.6% of individuals across the 2-year study suggests that at least a portion of the population is probably resident within study regions over long time periods. The largest groups (mean 6.28, range 1–31) were found in open waters and bays despite apparently low predation pressure. Indeed, shark bite scars – likely the result of unsuccessful predation attempts – were conclusively observed on only 1% of individuals. Although further studies are warranted, the high densities of dolphins suggest that they are an important upper trophic level predator in the coastal Everglades, but their ecological importance probably varies in space and time.