A detailed cartography of surficial sediments from Golfo San Jorge, Argentina is presented. Cluster analysis and principal components analysis (PCA) were applied considering the weight percentage of every granulometric fraction, carbonate concentration and the depth of 39 stations carried out during research cruises on board the RV ‘Captain Oca Balda’ (INIDEP).  The results defined three sectors: Sector 1, an area near the coast including Dos Bahías and Tres Puntas capes; Sector 2, a deep area far from the coast; and Sector 3, a coastal area and a south-east area between Tres Puntas cape and the inner area of the gulf. The first sector is characterized by the predominance of a coarse granulometric fraction and carbonate content. The second is defined by depth and presence of a fine granulometric fraction; while the third sector is considered a transitional sector, between the first and the second, dominated by fine sands. Sectors belong to environments of different kinds of energy or hydrodynamic conditions.

Submarine cliffs are typically crowded with sessile organisms, most of which are ultimately exported downwards. Here we report a 24 month study of benthic fauna dropping from such cliffs at sites of differing cliff angle and flow rates at Lough Hyne Marine Nature Reserve, Co. Cork, Ireland. The magnitude of ‘fall out’ material collected in capture nets was highly seasonal and composed of sessile and mobile elements. Sponges, ascidians, cnidarians, polychaetes, bryozoans and barnacles dominated the sessile forms. The remainder (mobile fauna) were scavengers and predators such as asteroid echinoderms, gastropod molluscs and malacostracan crustaceans. These were probably migrants targeting fallen sessile organisms. ‘Fall out’ material (including mobile forms) increased between May and August in both years. This increase in ‘fall out’ material was correlated with wrasse abundance at the cliffs (with a one month lag period). The activities of the wrasse on the cliffs (feeding, nest building and territory defence) were considered responsible for the majority of ‘fall out’ material, with natural mortality and the activity of other large mobile organisms (e.g. crustaceans) also being implicated. Current flow rate and cliff profile were important in amount of ‘fall out’ material collected. In low current situations export of fallen material was vertical, while both horizontal and vertical export was associated with moderate to high current environments. Higher ‘fall out’ was associated with overhanging than vertical cliff surfaces. The ‘fall out’ of marine organisms in low current situations is likely to provide an important source of nutrition in close proximity to the cliff, in an otherwise impoverished soft sediment habitat. However, in high current areas material will be exported some distance from the source, with final settlement again occurring in soft sediment habitats (as current speed decreases).

Intertidal meiofauna were collected from various locations around the Pina Basin, Recife, Brazil. The basin is a shallow restricted environment which receives large quantities of untreated sewage, and is therefore polluted, eutrophic and hypoxic. The meiofauna were identified to major taxa (nematodes, copepods, polychaetes, oligochaetes, turbellarians, gastrotrichs, rotifers, ostracods, acari, and juvenile amphipods and bivalves) and counted. Subsamples of nematodes were extracted and identified to the level of genus. The nematode community structure was typical of organically-enriched intertidal areas world-wide. Various environmental measurements were made, including sediment structure, salinity, dissolved oxygen and biochemical oxygen demand in the overlying water. Of these the latter two were shown to be most closely linked to variation in meiobenthic community structure. A much closer link was shown between variation in nematode assemblage structure, biochemical oxygen demand in the overlying water and gravel content of the sediment.

To investigate the palatability of abundant sub-Arctic sessile or sluggish invertebrates and their value as a food source, in situ experiments with natural consumer assemblages were performed in the Kongsfjord (Spitsbergen). These experiments were complemented with quantitative laboratory assays, using a generalist predatory starfish. Feeding preference and avoidance reactions were similar in both assays. Natural assemblages of predators in situ rejected nine out of ten species tested, and 12 out of 16 species were rejected in laboratory assays, indicating a high percentage of unpalatable invertebrates. Results were compared to the biochemical composition of the investigated species to see whether palatability and feeding preferences coincide with nutritional quality of the prey. Although nutritional quality, expressed as protein, lipid, nitrogen, carbon and water content, may account for some of the feeding preferences found, no overall relationship between nutritional value and palatability or feeding preferences was detected.

Periodic surveys of the subtidal epifaunal community on the gorgonian Melithaea flabellifera were conducted over a five year period at the Izu Peninsula, southern Japan. The occurrence patterns of epifaunal species on M. flabellifera were examined. The epifauna consisted of 16 species representing five phyla. The amphipod Incisocalliope symbioticus dominated (usually >80%) and occurred throughout the study.

The re-establishment of adult Lanice conchilega washed out from the sediment was studied in the laboratory in calm and wave conditions. Worms left in their tubes on the sand surface buried and built new tubes within 48 hours. In still water the fringe of the new tube was thinner and extended to all directions, while under a wave regime the individual branches were thicker and positioned perpendicularly to the direction of the waves.

The seasonal distribution of Leonnates persicus was studied along depth transects (10–200 m) of three stations located in the Levant Sea during February–November 2000. Leonnates persicus particularly dominated the slightly gravelly sand bottom of stations between 10 and 150 m. Its distributional pattern showed a seasonal trend: it inhabited depths between 40 and 150 m in February and May when surface temperature was below 21°C, whereas it preferred shallower waters (10–60 m) during the warm season (>29°C in August). The density of the species in the area varied between 10 and 130 ind m−2, with a maximum at 25–30 m off Erdemli in August.

The effect of light–dark cycle on the timing of larval release from jelly masses of the Mediterranean polychaete Eupolymnia nebulosa (Terebellida) was investigated. The larval emergence from the jelly mass occurs mainly during daylight. Results suggest that the larvae of E. nebulosa do not track the light–dark cycle endogenously.

The regeneration of cirri was followed in two common intertidal barnacle species, following non-lethal predation by an intertidal teleost. While >50% of damaged Semibalanus balanoides individuals showed some degree of cirral re-growth within 16 days, this level of regeneration was not reached in Chthamalus montagui until 32 days after removal of the cirri. Full re-growth of cirri required at least two moults in both species.

Enoplometopus callistus is reported for the first time from the Cape Verde Islands. In January 2001 two specimens were captured in depths of 100–150  m as by-catch in the lobster fisheries. One of them was dissected and kept in alcohol for future reference, the second one was put into an aquarium. The existing data on the distributions of the two Atlantic species of this genus, E. antillensis and E. callistus, indicate that the latter is restricted to the waters of the East Atlantic.

Although decorating behaviour is widely reported as a predator avoidance strategy among marine crabs, few studies have provided experimental evidence for this. Significance of decorating behaviour of the majid crab Tiarinia cornigera as antipredator response was examined by the field tethering and laboratory experiments. Survival of decorated crabs was significantly higher than that of non-decorated crabs after two days in an intertidal rock pool. In a laboratory experiment, crabs used more algae for decoration in the presence of predators (puffer fish) than when predators were absent. These data demonstrate that T. cornigera decorates with algae in response to predators to reduce predation pressure.

The patterns and variability of pinnation angle along the length of apodemes, and the scaling of apodeme surface area, were investigated in the American lobster (Homarus americanus) and the snow crab (Chionoecetes opilio) to assess the morphological variation between legs and species, and how these may affect force generation. Muscle fibre pinnation angle shows general patterns of decline along the disto-proximal axis of the apodeme, but the specific patterns of each apodeme or leg are highly variable. There is only small change in pinnation angle along the length of the apodeme or between flexed and extended positions. It appears that changes in pinnation angle are not of sufficient magnitude to contribute significantly to force generation in these pinnated muscle systems. The apodeme surface area as a function of carapace size shows positive allometry for all legs of the snow crab, and for some of the apodemes of legs 2, 3, and 5 of the lobster. The flexor apodeme within the snow crab is larger than the extensor in legs 2 to 4 implying a greater force generating ability in flexion than extension, and legs 2 to 4 all possess much larger apodemes than leg 5. The lobster indicates some specialization of apodeme surface area between the legs along the length of the body, with the anterior legs having larger flexor apodemes than extensor. This pattern is reversed for the last pair of legs. This suggests that each of the four walking legs of the lobster may generate approximately equal forces in extension, while leg 4 has the ability to generate greater forces in flexion than legs 2 or 3, which in turn likely produce larger forces than leg 5. The apodeme surface area is suggested to play a much greater role in determining force generation in crustacean walking legs.

This research reports on the kinematics of lobster and snow crab walking, documents changes in the moment arms of the mero-carpopodite joint during rotation, and examines scaling effects of morphological and mechanical variables in these crustacean species. Forward walking lobsters and lateral walking crabs were recorded and images analysed to describe the kinematics of these animals, and subsequently morphometric and moment arm measurements made. During forward walking the lobster maintains fixed mero-carpopodite joint angles during both the power and recovery strokes, though each of the walking legs maintains different joint angles. Legs 3 and 5 are maintained at angles which appear to equalize the flexor and extensor moment arms, and leg 4 joint angle appears to maximize the extensor moment arm. The snow crab has a joint excursion angle of between approximately 50° to 150° and, during flat bed walking, the leading and trailing legs move through similar excursion angles. The length of the meropodite for both species are longer for the anterior two leg pairs relative to the posterior two pairs and the rate of growth of the meropodite is largely isometric for the lobster while consistently increases with positive allometry in the crab. The flexor and extensor moment arms generated as the joint undergoes flexion/extension show two distinct patterns with the extensor moment arm being maximized at relatively low joint angles (55°–115°) and the flexor moment arm reaching a plateau at joint extension with angles between 95° and 155°. The flexor apodeme possesses the largest moment arms in all legs for both species, suggesting the flexors are able to generate greater torques. It appears that, mechanically, these laterally moving animals may be ‘pulling’ with the leading legs to a greater extent than ‘pushing’ with the trailing legs.

Moult cycle of Liocarcinus arcuatus in the Ría de Arousa (Galicia, north-west Spain) was analysed in relation to: (a) temporal changes; (b) spatial variability associated with both different environmental patterns (type of bottom, depth, etc.); (c) sex; and (d) body size. A total of 4275 females and 4103 males of L. arcuatus were caught in three different areas of the Ría de Arousa, selected as being representative of two types of habitat: a beach zone and two mussel raft culture zones (in the inner ría and in the outer area). Five moult stages were established on the basis of the degree of calcification in the exoskeleton. Only a small portion of the population (less than 15% in practically the whole year) were found monthly in one of the early postmoult stages (Stages A and B). Spatial and temporal variability of the moult cycle of L. arcuatus in the Ría de Arousa was found to be significant (P<0·001). There were no important spatial differences in the moult cycle of L. arcuatus females, by contrast, males showed a greater degree of spatial variability.

Spatial distribution patterns of two sessile gastropods belonging to Vermetidae, Vermetus triquetrus and Dendropoma petraeum, were studied in June 2001 in north-eastern Sardinia (Mediterranean Sea, Italy). Density of individuals was assessed within quadrats positioned on a shallow (0·1–1 m depth) rocky substrate of different lithological types (limestone and granite), at a hierarchy of spatial scales. Density of D. petraeum is significantly greater on granite than on limestone, while V. triquetrus does not show any differences related to rock type.

Temporal variations in copper, iron and zinc levels in the periwinkle, Littorina littorea, were investigated to determine whether levels were affected by the sex of the organisms and/or by the presence of two species of trematode parasite. Significant monthly changes in concentrations of all these metals were found, with levels varying according to periwinkle sex and parasite infection. Periwinkles infected by either Cryptocotyle lingua or Renicola roscovita had reduced copper and iron concentrations compared to same-sex uninfected periwinkles, although infected periwinkles generally contained higher concentrations of zinc. Periwinkles infected by the more invasive C. lingua rediae had lower copper concentrations than those infected by R. roscovita sporocysts. These results clearly indicate that in areas of high parasite prevalence L. littorea is not an ideal metal-biomonitor.

Feeding, as estimated by egestion rate, in coastal epibenthic mud snails Hydrobia ulvae living continually submerged in lagoon-like conditions varies significantly with time of day. Both in the field and in the laboratory, egestion rate is maximal around mid-day and minimal at twilight. This variation, here ranging in magnitude from mean lows of some nine faecal pellets h−1 to highs of 34 h−1, is consonant with likely rhythms of availability and productivity of their microphytobenthic food.

The Asian date mussel, Musculista senhousia (Mytilidae), is a good example of a species that has dispersed outwards from its native area through human-mediated transport, establishing sustainable populations in distant parts of the world. The date mussel, which is endemic in the Western Pacific region, appeared and became very abundant in the Sacca di Goro, a brackish lagoon in the Po River Delta (northern Adriatic Sea, Italy) in the early 1990s. Effects of M. senhousia on macrobenthic biodiversity were assessed over a ten year time period. At the study site, the increase in abundance and spread of M. senhousia resulted in an alteration of the pre-established macrobenthic community. Changes in benthic dynamics seemed apparent, through the inhibition of epifaunal, suspension-feeding taxa (Ficopomatus enigmaticus, Mytilaster minimus), and the enhancement of detritivores (Neanthes succinea, Streblospio shrubsolii, Microdeutopus gryllotalpa). It is hypothesized that the Asian date mussel was initially successful because it exploited a naturally disturbed, sparsely occupied environment, rather than interjecting itself among and displacing existing species. Musculista senhousia acted, at least initially, as a colonizer rather than an invader.

The first record of Musculista senhousia in the Taranto seas (eastern-central Mediterranean Sea) is reported. The species was mostly found on bottoms with pleustophytic algal felt where densities up to 3800 specimens per square metre were estimated. The sizes in the sampled population ranged from 5·16 to 30·59 mm. Two main modal components were detected around 11·67±0·67 mm and 18·00±2·38 mm.

The impact of experimental dredging was assessed on the venus clam Chamelea gallina from seabeds off the Lagoon of Venice. Commercial-sized clams were collected using high water pressure and mechanical sorting (HP), as in professional fishing, and low water pressure without sorting (LP). To highlight the effects of acute stress due to the different approaches in harvesting clams, various biological responses were evaluated at both organism and cell level. Filtration and respiration rates showed opposite behaviour, the former significantly decreasing, the latter increasing, when mechanical stress was higher. Consequently, lower values of scope for growth in HP clams were observed. The survival in air test exhibited significantly lower median survival time values (LT50) in more severely stressed animals. The haematocrit value and phagocytic index significantly decreased in HP samples, revealing a detrimental effect on mechanisms of immunological defence. Acid phosphatase and β-glucuronidase activity was also affected by increasing mechanical stress, even though an opposite trend was shown in the two investigated enzymes. Lastly, higher damage levels were detected in shells of HP clams.