Age and length data of 291 franciscana dolphins (Pontoporia blainvillei) incidentally captured on the coast of Rio Grande do Sul State (RS), southern Brazil, were used to fit growth curves using Gompertz and Von Bertalanffy growth models. A small sample of franciscanas (N = 35) from Buenos Aires Province (BA), Argentina, were used to see if there are apparent growth differences between the populations. Male and female franciscana samples from both areas were primarily (78–85%) <4 years of age. The Von Bertalanffy growth model with a data set that excluded animals <1 year of age provided the best fit to data. Based on this model, dolphins from the RS population reached asymptotic length at 136.0 cm and 158.4 cm, for males and females, respectively. No remarkable differences were observed in the growth trajectories of males and females between the RS and BA populations.

International efforts are currently being made to establish networks of marine protected areas (MPAs) for the purposes of conservation of marine biodiversity. One of the primary objectives of MPA networks is to achieve representation of all marine biological diversity. Since we do not know the extent of biological diversity nor its distribution and function, we use surrogates to represent biological diversity. At a broad scale, measures of the physical environment are used, however at a fine scale biological assemblages have been shown to provide better representation of known biological diversity. While there are well known descriptions of assemblages for shallow water environments, few such descriptions of deep-sea benthic assemblages have been attempted. This paper provides descriptions of deep-sea epibenthic megafaunal assemblages based on a broad-scale video and stills image survey of the upper bathyal (200–1000 m) regions of the Rockall Trough and eastern Faroe–Shetland Channel. One thousand nine hundred and eighty-seven images were analysed from 139 video transects sampled from Dangaard and Explorer Canyons, Rosemary Bank Seamount, Hatton Bank, Wyville-Thomson Ridge, and the continental slope west and north-west of Shetland. Quantitative data obtained were analysed using cluster analysis and SIMPER analysis in Primer V.6 to identify benthic assemblages and their characterizing species. Thirty-one epibenthic megafaunal assemblages are defined by their characterizing species, and their distribution in terms of site, depth, temperature and substratum type. These 31 ‘biotopes’ provide consistent units for use in biological mapping efforts and assessments of representativeness in MPA network design. To facilitate the incorporation of these biotopes into existing deep-sea classification systems the biotopes have been assigned to broad substratum types. This is consistent with the use of substratum as a surrogate in many existing systems.

The spatial distribution of Farfantepenaeus shrimp was analysed in the Laguna Madre of Tamaulipas, Mexico. Sampling was carried out on submerged aquatic vegetation (SAV) habitats at five sites located along the coastal lagoon. Two nocturnal surveys were conducted during winter in 2005 (January–February), collecting a total of 3268 shrimp individuals. SAV beds were composed of a mixture of drift algae (mainly Digenia simplex), attached algae (mainly Penicillus capitatus and Udotea occidentalis) and seagrass (mainly Halodule wrightii). Farfantepenaeus aztecus was more abundant (39.5%) than F. duorarum (36.8%), and the remaining 23.7% corresponding to small unidentified Farfantepenaeus spp. were classified as recruits. Abundance of F. aztecus was significantly higher at sites 2 and 4, whereas F. duorarum did not show significant distribution differences along the Laguna Madre. Recruits, juveniles and total shrimp tended to decrease significantly at the northern part of the lagoon (site 1), where substrate was dominated by drifting algae and seagrasses were scarce or absent. The abundance of shrimp was positively related to seagrass biomass and/or water temperature, whereas there was a negligible or negative relationship with algal biomass. With the exception of subadults, a significant positive linear relationship between seagrass and shrimp abundance was fitted, indicating an increase in number of individuals of both species with increasing seagrass biomass. This suggests that seagrass is the most important component of SAV beds influencing the abundance of F. aztecus and F. duorarum along this hypersaline coastal lagoon.

The relative growth and population structure of the terebellid Nicolea uspiana were investigated in the intertidal zone of a rocky shore on the south-east coast of Brazil, from May 2006 to May 2007. Eight hundred and forty-seven individuals of N. uspiana were analysed: 391 males, 163 females, and 293 immatures. Although significant differences in some morphometric parameters were found, there was no sexual dimorphism between males and females. There were differences in total length, width of segment 5, and length of the notopodial region between matures and immatures. The negative allometry of the total length in relation to five other parameters showed that this feature is a good measure for estimating the individual size, which was then used in the analysis of population structure. This population of N. uspiana showed a bimodal size–frequency distribution, with immature and mature individuals found during the entire year. This pattern indicates continuous reproduction, with each cohort growing for at least three to four months and being responsible for two consecutive settlement peaks.

Even if artificial reef studies heavily refer to the distinction between resident and transient species, there is still no widely-shared available method to distinguish objectively these two groups. Such an absence makes any comparison between studies difficult. This study aims to test whether the four objective distinction methods successfully applied to a 21-year-long time-series on fish assemblage in an English estuary may be as successful when applied to marine artificial reefs. For such a purpose, we tested each distinction tool separately with reference to four different artificial reef fish assemblage datasets. Three of them were drawn from the literature. Results indicate that none of these tools, used either individually or collectively, provide an efficient solution to distinguish resident species for the four datasets considered. We suggest that one of the major reasons for this failure may lie in the relative sampling size. Nonetheless, as these four datasets are representative of the datasets generally reported in the literature, tools capable of distinguishing reliably and efficiently resident from transient species along artificial reefs have yet to be developed. However, such a development requires fish residence to be previously and accurately defined by artificial reef scientists and managers.

An ex-Royal Navy frigate, HMS ‘Scylla’, was placed on the seabed in Whitsand Bay, south Cornwall on 27 March 2004. After five years, the reef supported a mature steel wreck community. The colonization of the reef showed wide fluctuations in species abundance in the first two years but, by 2006, most species that dominated or characterized the reef after five years had settled. Significant colonization events included settlement of barnacles, tubeworms and hydroids within a month and remarkably high settlements of the sea urchin Psammechinus miliaris and the queen scallop Aequipecten opercularis in the first year together with starfish Asterias rubens, solitary sea squirts and ephemeral algae. The plumose anemone Metridium senile, a characteristic species of wrecks, arrived in late summer 2004 but the widely distributed dead man's fingers Alcyonium digitatum was not observed until spring 2005. Wrasse were slow to colonize the reef but were established in small numbers by the end of 2007. Sea fans, Eunicella verrucosa, were first observed in August 2007. The species count for the reef stood at 263 taxa by the end of March 2009. The inside of the reef remained poorly colonized even after five years. Areas coated with tributyltin (TBT) antifouling paint only had colonization where the paint had flaked-off or on non-toxic paint markings, but with some indication that colonization may be occurring by a very few species especially near to non-TBT areas. Many species characteristic of natural reefs had not settled and neither do they occur on older wrecks including branching axinellid sponges, some cushion sponges and the yellow cluster anemone Parazoanthus axinellae. The artificial reef developed a community that was distinctly different to nearby natural rock reefs and such artificial structures should not be considered as a replacement for damaged or destroyed natural habitats.

Using aquaria containing natural sediment, medium-term burrow development was investigated. After initial construction, and over the first month, relatively little burrow development was observed in terms of the number of openings and tunnels created. After an additional six months, however, there was a significant increase in the number of openings and tunnels constructed. In contrast to what might be expected from the number of openings and tunnels created during this period, a significant proportion of the sediment movement was sub-surface and relatively little sediment expulsion occurred. The concentration of nitrite, ammonia and phosphate in the burrow water was generally greater than that of the surface water, whilst the nitrate and sulphate measurements showed no particular pattern. Only the differences in phosphate concentrations were found to be significantly different. These results were indicative of Calocaris macandreae influencing rates of denitrification. This study also provided further evidence of carnivory and caching behaviour in this species.

Natural populations of Aurelia aurita scyphopolyps, settled on a wreck in the northern Adriatic Sea, were monitored for 22 months in order to study their seasonal cycle. The trend of Aurelia polyps is strongly dependent on water temperature with a peak of abundance in summer and low densities in winter. The strobilation process occurs only once a year, during the cold season, and the estimated number of released ephyrae is 780,000–2,600,000/m2. The species has been recorded only on the iron wreck while it is completely lacking from the close rocky cliff of Conero Promontory, suggesting that the increase of underwater structures of anthropogenic origin could be related to the increases of jellyfish biomass.

Pinna nobilis is an endemic bivalve of the Mediterranean Sea. In the last decades P. nobilis populations have declined drastically due to increasing anthropogenic pressure and it has been declared a protected species since 1992. Despite the need for conservation, knowledge of the ecology and monitoring of the main populations of P. nobilis are limited. This study considered a population living within a Posidonia oceanica meadow in the Gulf of Oristano (western Mediterranean, Italy). The study area, about 150 hectares, part of which is included within a Marine Protected Area and a Site of Community Importance, was subdivided in 3 sub-areas. The percentage cover of different habitat types (P. oceanica, dead matte and sand) in each sub-area was measured and meadow features (substrate coverage, matte compactness and shoot density) characterized. The hypotheses of differences in density, percentage of dead individuals, population structure, shell burial level and orientation of P. nobilis, were investigated according to sub-areas and to habitat type. The spatial distribution was patchy, and the habitat type resulted a key factor in determining both density and distribution. A strong edge effect was demonstrated: more than half of the observed individuals colonized the P. oceanica border. Matte compactness and shoot density were found to affect the density and distribution of P. nobilis. Shell burial level and percentage of dead individuals varied with sub-areas and habitat types. Size distribution was bimodal and common shell orientation was observed in two sub-areas. These results contribute to increase the knowledge of population ecology of this species and to provide useful information for implementing conservation policies.

The white-beaked dolphin Lagenorhynchus albirostris is the most numerous cetacean after the harbour porpoise Phocoena phocoena in the North Sea, including Dutch coastal waters. In this study, the diet of 45 white-beaked dolphins stranded on the Dutch coast between 1968 and 2005 was determined by analysis of stomach contents. Although 25 fish species were identified, the diet was dominated by Gadidae (98.0% by weight, 40.0% in numbers), found in all stomachs. All other prey species combined contributed little to the diet by weight (2.0%W). The two most important prey species were whiting Merlangius merlangus (91.1% frequency of occurrence (FO), 30.5%N, 37.6%W) and cod Gadus morhua (73.3%FO, 7.4%N, 55.9%W). In numbers, gobies were most common (54.6%N), but contributed little to the diet by weight (0.6%W). Three stomachs contained different prey compared to the others: one animal had taken 2250 gobies, accounting for 96.4% of all gobies found; one animal had fed on 29 small sepiolids; and one animal had solely taken haddock Melanogrammus aeglefinus. Squid and haddock were not found in any other stomach. The overall diet showed a lasting predominance of whiting and cod, without clear changes over time (35 years) or differences between sexes or size-classes of dolphins. This study adds to earlier published and unpublished data for Dutch coastal waters and agrees well with studies of white-beaked dolphins from other parts of the species’ range, in the North Sea and in Canadian waters, with Gadidae dominating the diet on both sides of the Atlantic.

Over a 52-month period beginning in May 2004 and concluding in August/September 2008, and coinciding with the period over which tributyltin was banned as a ship anti-foulant globally, a population of the dogwhelk, Nucella lapillus on the south-eastern coast of England, was studied for changes in population size and structure, reproduction and feeding behaviour. During the study period, the size of the N. lapillus population grew from ~25 individuals to >500, i.e. a 20-fold increase, and recovery from imposex was total. Significant changes in feeding behaviour were also reported. For example, peaks in N. lapillus predation were recorded over the winter months, but as population size increased, this temporal seasonality was masked due to the growing numbers of juveniles feeding on smaller and smaller individuals of Mytilus galloprovincialis (as opposed to barnacles) as the study progressed. Similarly, with freedom from imposex, the numbers of failed drilling attempts declined and numbers of prey with more than one drill hole increased as the incidence of kleptoparasitism increased. Predated M. galloprovincialis were also increasingly attacked in the antero- and postero-dorsal quadrants of their shells as the study progressed. Contrary to expectations, only a slightly positive relationship between predator and prey sizes was recorded overall however, suggesting that beyond a shell height of ~13 mm, when the transition from barnacle to mussel feeding occurs, M. galloprovincialis individuals of virtually any size are preyed upon by N. lapillus.

The aim of this study was to compare the population structure of the invasive bivalve Isognomon bicolor in three different areas on the coast of Rio de Janeiro State and to verify its temporal variation. All the areas presented high densities, reaching more than 1000 live individuals per 100 cm2. The number of dead individuals and recruits was higher in Ilha do Brandão (Angra dos Reis) than in the other areas. The individuals sampled at Praia Vermelha (Rio de Janeiro) presented the highest maximum and mean sizes, compared to those found at Ilha do Brandão. In this area, vermetid molluscs are dominant and build a complex reef structure where only a few individuals of I. bicolor can really grow.

The LS5096 h of prawn, Palaemon elegans, was determined at various salinities (0–45 ppt) with the Caspian Sea salt proportion. In addition, growth indices, survival and moulting at salinities 8, 13 and 18 ppt were also studied during four weeks. All the experiments were carried out in the laboratory (24±1°C). The results showed that more than 50% of the prawns survived at 1 to 30 ppt salinity range, while above and below this range, less than 50% survived within 24 hours. No significant differences (*P > 0.05) in growth parameters such as carapace length (CL) increase, specific growth rate (SGR) and also in survival and moulting rates were observed in prawns reared in salinities 8, 13 and 18 ppt. Mean intermoult period in each salinity was 8.12 ± 3.07, 8.61 ± 2.96 and 8.92 ± 3.47 days, respectively. Salinity 8–18 ppt was found to be the optimum range for P. elegans in the studied length range (CL, 6–9 mm).

Congrids inhabit the warm and temperate seas of the world, from the coastline to the slope of various continents. Many of its species are much valued by commercial and artisan fishing; nevertheless, at world level, there is great ignorance about the life cycle of the members of this genus. Some species of the genus, such as those from the North Atlantic, appear to be semelparous, for they cease feeding, decalcify, loose their teeth and migrate to deep waters to spawn. Specimens of the southern conger eel Conger orbignianus were examined for the purpose of learning about their biology in waters of the western South Atlantic. Histological sections were analysed from ovaries of coastal conger specimens from the North Argentina coastal littoral, the Argentine Sea deep waters, and the giant congers from southern Brazil. Two oocitary generations have been observed in coastal females typical of total spawners, with a previtellogenetic batch that does not reach maturity, and a vitellogenetic batch that does it together with its size, completely surrounded by adipose tissue. The ovaries of fish captured in deep waters occupied the whole abdominal cavity, with scarce adipose tissue and degraded body. The giant congers from southern Brazil were captured in very deep waters, healthy, with few atretic oocytes and abundant adipose tissue. Evidence of semelparity was found in the southern conger eel; the asistosis stage, the body degradation during the reproductive migration and gigantism might be common attributes in other species of the genus.

Morphogenetic events during the division of the marine ciliate, Euplotes vannus (Müller, 1786) Diesing, 1850 were investigated using protargol impregnation: (1) the opisthe's oral primordium develops de novo in a subsurface pouch above the marginal cirri; (2) the cirral anlagen for the frontal, ventral and transverse cirri in both dividers develop separately on the surface epi-apokinetally, cirrus I/1 and marginal anlagen for daughter cells are formed de novo separately; (3) the dorsal kinety anlagen occur in a non-typical primary pattern within the parental structures at mid-body, of which the 3 right-most ones produce the 3 caudal cirri for the proter; and (4) the opisthe acquires 2 caudal cirri from the end of the right-most 2 kineties. Based on the data available, the reasons for the variation in the number of caudal cirri in E. vannus are discussed.

Stomach content analyses were performed in 28 dolphins stranded between 1994 and 2007 on the beaches of Rio de Janeiro State (23°06′S 44°18′W/22°14′S 41°54′W), Brazil, comprising six delphinid species: Stenella frontalis (N = 10), Steno bredanensis (N = 7), Tursiops truncatus (N = 4), Delphinus delphis (N = 5), Lagenodelphis hosei (N = 1) and Stenella coeruleoalba (N = 1). Fish otoliths and cephalopod beaks were used to identify the prey species and to estimate the original length and weight. Seven different cephalopod species from six families and 15 fish species belonging to 10 families were identified. Although the fish contribution could be underestimated, cephalopods constituted the group of higher importance, revealing that these invertebrates may represent an important source of energy for delphinids in the region. In this context, the squid Loligo plei should be highlighted due to its important contribution. Most preys were coastal and demersal, and such consumption could indicate coastal foraging habits of the quoted dolphin species. Although dolphins consumed many species of prey in common, they fed on different size-classes of prey. The foraging area of the dolphins could be the same region used by fishing operations, which would represent a risk for incidental capture.

A large (100 km) rocky coast intertidal was sampled several times (from 2004 to 2006) to assess the affection degree of invertebrate assemblages impacted by a continuous oil spill. Twelve locations and two intertidal heights were selected along the coast representing two spatial scales (kilometres and tens of metres). Univariate and multivariate analyses of variance were used to test whether faunal assemblages exposed to different intensities of oil disturbance differ in terms of diversity, total cover, key species cover and trophic guilds. Whereas no significant differences in midshore assemblages were noted, the low intertidal zone exhibited comparatively lower abundance values of the limpet Patella ulyssiponensis at worst affected sites. Besides, a generalized increasing diversity trend was found in the low intertidal from 2004 to 2006. Natural variability of communities is also discussed as the cause of the differences we observed. With respect to spatial and temporal scales of variation, mid- intertidal communities showed a more consistent structure, while lowshore assemblages were markedly heterogeneous in practically all the variables measured.

To demonstrate the effectiveness of microarrays for the detection of jellyfish, we developed a low density DNA chip based on the mitochondrial COI gene sequences of scyphozoans (jellyfish). We designed species-specific oligonucleotide probes by sequence comparisons between scyphozoans and other cnidarians such as hydrozoans and anthozoans. Each amine-labelled capture probe was arrayed onto a silylated slide. PCR products of the COI gene were hybridized to the DNA microarray that contained COI consensus sequences. We tested the ability of the DNA chip to discriminate between species from the genera Aurelia and Chrysaora based on samples of both species from the polyp and ephyra stages. The array produced unique hybridization patterns for each of the two tested jellyfish species. Furthermore, we were able to simultaneously detect individual jellyfish species from mixtures of these two different species in the laboratory and from environmental samples. These results show that the low density DNA chip that we designed can be used as a technical platform for parallel molecular detection of various jellyfish species.

The Atlanto-Mediterranean holothurian Holothuria tubulosa is among the conspicuous benthic invertebrates in the shallow sublittoral zone. It is an edible species, harvested at the Aegean Sea and utilized as fishing bait. Considering the lack of information for the Aegean populations, a one-year survey, based on monthly or semimonthly samples, was carried out focusing on population structure, allometric relationships and reproductive status of H. tubulosa stocks in Pagasitikos Gulf. Population density varied around 9.93 individuals/100 m2. This value was rather low compared with other studied Mediterranean populations of the species, possibly due to the scarcity of seagrass meadows in the area studied. All measured biometric characters showed high plasticity, and all the examined morphometric relationships followed negative allometry indicating a change to the shape of the animal's body as it grows. Holothurians’ length was a moderate predictor of biomass since r values reached 60%; in contrast a very strong relation was observed between drained and gutted weight. Size–frequency distribution analysis was unimodal with the exception of spring where a second mode of larger sized individuals appeared. The gonadosomatic index showed a single spawning season per year, in late summer; accordingly the reproductive cycle of the species showed a clear annual pattern which was highly correlated with the seasonal variations of temperature.

Size-based analyses of marine animals are increasingly used to improve understanding of community structure and function. However, the resources required to record individual body weights for benthic animals, where the number of individuals can reach several thousand in a square metre, are often prohibitive. Here we present morphometric (length–weight) relationships for 216 benthic species from the North Sea to permit weight estimation from length measurements. These relationships were calculated using data collected over two years from 283 stations. For ten abundant and widely dispersed species we tested for significant spatial and temporal differences in morphometric relationships. Some were found, but the magnitude of differences was small in relation to the size-ranges of animals that are usually present and we recommend that the regression relationships given here, based on pooled data, are appropriate for most types of population and community analyses. Our hope is that the availability of these morphometric relationships will encourage the more frequent application of size-based analyses to benthic survey data, and so enhance understanding of the ecology of the benthic/demersal component of marine ecosystems and food webs.