Survey work was carried out in the Greater Minch area on the west coast of Scotland in 1997. The survey covered an area of 17,000 km2, extending from Kinlochbervie in the north-east to the Stanton Banks in the south-west. Acoustic and ground-truth surveys were conducted using the seabed discrimination system RoxAnn© and underwater television cameras. This paper examines the macro infaunal component of the benthic community from 28 stations sampled throughout the region. From these, 198 taxa were identified, while species per station ranged from 11 to 69 with a maximum abundance of 2100 individuals per m2. Biomass ranged from 2·3 g m−2 to 103·1 g m−2, with a mean value of 21·0 g m−2. Multivariate statistical analysis of the infaunal data revealed the presence of three benthic assemblages, which were closely related to habitat type. An investigation into the dominant feeding guilds or isotrophic groups from each assemblage revealed that surface deposit feeding dominated the very fine sand habitats while both surface and subsurface deposit feeding were very common in the silt communities. A combination of feeding types (namely carnivorous, suspension and surface-deposit feeding) was associated with the sand habitats. The findings of this study are discussed in relation to those in similar habitat types.

The presence of suctorian ciliates attached to the cuticle of heavily ornamented free-living marine nematodes, especially the family Desmodoridae, has been reported. Observations of nematode hosts and their attached ciliates were made from samples extracted from very fine muddy sands of tropical Australian sea grass meadows. Measurements of the point of attachment of the ciliates revealed that they tend to position themselves near the anus/cloaca of the nematode host.

Specimens of the marine isopod Excirolana chiltoni collected in Hokkaido (northern Japan) showed epibiont protozoan ciliates belonging to two species of loricate suctorian: Acineta hokkaidensis sp. nov. and Acineta excirolensis sp. nov. Acineta hokkaidensis is larger, with an elongated body covered by a lorica. The short stalk had 15–18 longitudinal striations. The contractile vacuole was located apically. The macronucleus was posterior. Two fascicles of capitate tentacles located at the edges of the apical area project through the anterior aperture of the lorica. The suctorians were found on the pereiopods and antennae of the isopod. Acineta excirolensis which is smaller and triangular in shape, showed a very wide lorica and a noticeably long stalk. At the edges of the apical region there were two lobulate actinophores, each with a fascicle of capitate tentacles. The contractile vacuole was anterior and spherical, and the macronucleus was central. These suctorians were attached as planobionts on the pereiopods of the isopod. The taxonomic position of both species was analysed in relation to other similar species previously described.

The detail of the characteristic double whorled branchial crown of the tubiculous polychaete Bispira volutacornis, with its internal skeleton of large vacuolated cells and ciliated radioles, is consistent with the feeding apparatus of sabellids at large. Studies show that ingested particulate matter has at least one dimension less than 15 μm. Feeding seems to be most readily accommodated at current speeds from 1 cm s−1 to 3 cm s−1 with the crown apex angled downstream. Particulate matter passes through the alimentary canal in 7·7 h at 14°C, for an average sized specimen of 97 segments. Whilst the tube provides protection against predatory fish and crustaceans (with ample evidence of sub-lethal cropping of the branchial crown), it also has a role in irrigation and respiration. The worm will retreat within the tube when current flow exceeds 8·7 cm s−1.

Field studies were carried out along a Mediterranean rocky shore to describe the foraging behaviour of the hermit crab Clibanarius erythropus, a common intertidal Diogenidae. The spatial strategy adopted during foraging activity was investigated through monitoring the movement of ten individuals, each followed for two hours. This revealed that hermit crabs maximized the space explored while in search of food and that shell type was one factor influencing the extent of movement. The evaluation of hermit abundance on different algal substrates provided clues to understanding the pattern of food utilization. This study shows that ‘generalist’ hermit crabs display a certain degree of selectivity, mostly foraging on assemblages of filamentous algae and corticated macrophytes. The conclusion is that C. erythropus selects substrates where good foraging can occur; whether hermit crabs eat within the selected substrates every food item they encounter or select food at the level of individual items is still an unanswered question.

During remotely operated vehicle operations on the UK continental shelf to the west of Shetland (60°6′N 4°4′W) at a depth of 400 m, Munida sarsi, a common benthic crustacean was observed actively preying on the northern krill Meganyctiphanes norvegica. Video footage shows the individual using its chelipeds to catch prey items as they swarm around its burrow. These initial observations indicate that predation forms a new feeding strategy for a species previously believed to be an active scavenger.

The feeding behaviour of stage I–III phyllosoma of the spiny lobsters Jasus edwardsii and Jasus verreauxi was recorded to determine the sequence of events and sensory mechanisms involved in the feeding process. All phyllosoma exhibited a characteristic tumbling behaviour prior to making contact with an individual Artemia and feeding behaviour was similar between the two species. Tactile contact with pereiopods 1 or 2 was necessary to initiate a prey capture response which involved spearing of Artemia, using the terminal dactyl present on these two pereiopods and then passing the prey forward to the mouth with the maxillipeds.

Scanning electron microscopy (SEM) of the pereiopods revealed two morphologically distinct receptors present on the distal segments. These receptors are suggested to have tactile and chemoreceptive roles.

The abundance patterns of copepods on the Juan de Fuca Ridge was examined. One species was studied in detail. Twelve non-parasitic species are recorded from the Juan de Fuca, but only three dirivultid species and some unidentified harpacticoids are abundant in collections. Densities are estimated at 0·5 copepod cm−2 on vestimentiferan tubes to over 8 cm−2 on chimney surfaces. Aphotopontius forcipatus is most abundant at new vents and Benthoxynus spiculifer is most abundant at mature vents. Vents with reduced or undetectable fluid flow have higher diversity of copepod fauna.  The life cycle of the siphonostome Stygiopontius quadrispinosus begins with a centrolecithal egg brooded singly or doubly on the female. Hatching and naupliar stages are unknown in benthic samples. The preadult stage (copepodite V) recruits to the vent habitat. Pre-adult males attach to pre-adult females and fertilize at the final copepodite VI moult. As the sex ratio is highly skewed in favour of females, males probably inseminate many females and there may be mate competition in populations where males are rare. Reproduction is probably continuous or semi-continuous. Abundance is greatest on sulphide edifices near the points of hot water egress. This copepod co-occurs with the alvinellid polychaete Paralvinella sulfincola.

The feeding biology of Bathypecten vulcani, a peri-hydrothermal vent pectinacean, was investigated using histological and scanning electron microscope studies of the gills and stomach contents of specimens sampled from the 9° and 13°N sites of the East Pacific Rise. Salient characteristics were compared with those of Bathymodiolus thermophilus from the same and similar habitats. The gills of Bathypecten vulcani displayed heterogeneous organic and mineral particles on their frontal surface. The digestive tract possessed well-developed structures (whose anatomical and cytological characteristics indicated full functionality), typically found in bivalves from littoral aerobic environments, as well as in Bathymodiolus thermophilus, which is capable of suspension-feeding: oesophagus, stomach, crystalline style, digestive gland, and intestine. Observations of stomach contents revealed diverse particles from the photic zone, including debris from diatoms and coccolithophorans. In contrast to Bathymodiolus thermophilus, bacteria were rarely observed in the digestive tract, indicating a more complete reliance on surface-originating particles.

The sediment surface within the Osbornia belt of a mangal on Pulau Hoga, Tukang Besi Islands, Sulawesi, Indonesia, is dominated inter alia by deposit-feeding gastropod molluscs at a mean density of some 230 ind m−2 although, unusually, species of Cerithidea do not occur. Densities of the two most numerous species, the potamidid mud-whelk Terebralia sulcata and the Cerithidea-like cerithiid mud-creeper Cerithium coralium, are inversely correlated, although the species occurred together in 42% of quadrat samples. Within and beyond the normal range of field densities of each species (C. coralium mean 153 m−2; T. sulcata mean 75 m−2) there was no evidence of intraspecific depression of feeding rate, as assessed by the production of faecal pellets, although this was significantly reduced in the occasional very high density aggregations of C. coralium (>1100 m−2). The presence of the larger T. sulcata did appear to have a strong inhibitory effect on feeding in C. coralium; the converse, however, could not be demonstrated. Abundances of Terebralia palustris and C. coralium were also inversely correlated where the two co-occurred.

The diet and predatory behaviour of the nudibranch Roboastra europaea (Mollusca) is described and compared with other nudibranch-hunting opisthobranchs. The natural diet in the Strait of Gibraltar was studied by the analysis of gut contents. Roboastra europaea is a specialist predator of nudibranchs, and the diet is comprised essentially of the polycerids Polycera sp., Polycerella emertoni, Limacia clavigera and conspecific R. europaea. One or several Polycera species appeared as the most dominant prey.  The complete assemblage of potential prey of this predator—the fundamental diet—was assessed in laboratory trials that included all likely prey groups. This predator consistently rejected both non-nudibranch species and non-polycerid nudibranchs. Roboastra europaea is exclusively a predator of polycerids and previously unencountered polycerids are also potential prey items.  As most of the hunter opisthobranchs, R. europaea exhibited cannibalistic behaviour, to the extent that aggressiveness prevailed over mating in intraspecific encounters. Roboastra europaea as prey showed a complex result in laboratory trials: (a) if one individual was small enough complete ingestion proceeded; (b) if there was not enough difference in size, a cannibal attack proceeded, but if ingestion was not possible, it could result in mating behaviour.

The common phenomenon of sublethal predation in soft-bottom bivalves usually involves nipping of siphons. Here we show that foot cropping, hitherto documented only in Donax spp., is widespread in the New Zealand cockle Austrovenus stutchburyi (Veneridae). Depending on the locality, cropping frequency ranged between 14 and 34% of cockles, and the average proportion of the foot area cropped ranged between nine and 21%. Estimates of biomass lost to croppers at the time of sampling varied between 235 and 2040 mg ww m−2. It is emphasized that foot cropping in Austrovenus is likely to affect the population dynamics of the cockles.

The aim of this study is to improve rearing device of Crepidula fornicata (Mollusca: Gastropoda) reported in the literature, by determining the best arrangement between densities and feeding frequency in reared enclosures. Optimal growth (26·4 μm d−1) and survival rates (55·1%) were obtained when larvae were reared at 500 ind l−1 and fed every two days.

Natural abundance, 13C/12C ratios (δ13C) of Californian sea hares, Aplysia californica, (Gastropoda: Opisthobranchia) were measured for comparison with the animals preferred red algal diets, Plocamium cartilagineum and Laurenciapacifica. Isotopic compositions of animals collected from around Santa Catalina Island, did not reflect those of the favoured red algal diets, nor the majority of algal species found in the field. However, animals held in seawater tanks and fed diets with a constant carbon isotopic composition exhibited δ13C values similar to their food. Fast turnover tissue, such as the muscle tissue of actively growing juveniles or egg masses laid by adults, showed δ13C values within ±2‰ of the algal diet. Slow turnover tissue, such as the muscle tissue of large adults, reflected the diet over several months. Stable carbon isotope ratios thus proved a useful tool to clarify the extent to which specialized feeding in A. californica can occur upon algae which are only moderately to rarely common.

Stomach contents of 533 jumbo squid, Dosidicus gigas, ranging between 14·5 and 87·5 cm dorsal mantle length were collected on a monthly basis in the central Gulf of California from November 1995 to April 1997. Fish prey were identified by sagittal otoliths, cephalopods by beaks and crustaceans by exoskeletal features. The diet was dominated by Benthosema panamense, an abundant near-shore nyctoepipelagic myctophid that forms dense aggregations. Another myctophid, Triphoturus mexicanus, several micronektonic squid, pelagic red crab and small pelagic fish such as northern anchovy and Pacific sardine played a secondary role. The largest differences in diet were due to spatial and monthly changes, while differences regarding squid size or sex were smaller. Prey size (averaging 5–7 cm) and prey number did not vary with size of jumbo squid. Jumbo squid in the slopes of the Guaymas basin feed on abundant schooling mesopelagic micronekton of annual nature with a quick response to environmental changes, which could partly explain the large annual fluctuations of this commercial resource.

Specimens of the onychoteuthid squid Moroteuthis ingens were collected from four sites in the Southern Ocean: Macquarie Island, the Falkland Islands, the Chatham Rise (New Zealand) and the Campbell Plateau (New Zealand). Spatial variations in diet among these areas were investigated using stomach contents and lipid and fatty acid profiles. Myctophid fish were prominent prey items at all sites, and the diet at New Zealand sites contained temperate myctophid species that were not identified at other sites. The diet at the Falkland Islands differed considerably from other sites due to the large proportion of cephalopod prey that had been consumed by M. ingens. This is likely to be due to the absence of key myctophids, such as Electrona carlsbergi, and the abundance of smaller squid such as Loligo gahi and juvenile M. ingens over the Patagonian Shelf. Stomach contents data could not be used effectively to determine dietary differences between the Chatham Rise and Campbell Plateau, largely due to differences in sample sizes between these sites. Lipid class and fatty acid profiles of the digestive gland indicated that the diet of M. ingens differed significantly between the Chatham Rise and Campbell Plateau, despite the relative proximity of these sites. We conclude from total lipid content that this was due to a reduction in food availability to M. ingens at the Campbell Plateau. The highly productive waters of the Subtropical Front pass over the Chatham Rise, whereas the Campbell Plateau is situated in less productive sub-Antarctic water. Differences in oceanographic conditions are likely to have driven dietary variations between these two sites.

Population structure and biology of Octopus vulgaris was investigated along the south-eastern coast of South Africa. Samples were collected inter- and sub-tidally as a precursor to the establishment of an experimental octopus fishery in the region. In total, 300 (intertidal) and 147 (subtidal) O. vulgaris were collected over a two year period. Females were found to dominate the intertidal area (sex ratio 2:1), while no difference was found subtidally (sex ratio 1:1). Of those collected intertidally, immature females were most prevalent while males ranged from immature to mature. Mature females were only found subtidally. A marked size difference was apparent, with the subtidal octopus being substantially larger. Although brooding females were found throughout the year, numbers peaked in summer. Individual fecundity ranged between 42,000–790,000 eggs. The total number of eggs produced and the number of eggs per egg string were correlated to female size. Diet did not vary greatly between the inter- and sub-tidal areas, with the main prey items being crustaceans, teleosts and octopus. It appears that the immature females use the intertidal area to feed and grow, before migrating to deeper areas to mature and spawn.

Seasonal variations in feeding physiology and scope for growth of green mussels Perna viridis (Bivalvia: Mytilidae) were investigated in Ma Wan, an estuarine mariculture site located in the southern waters of Hong Kong. Total particulate matter, particulate organic matter, particulate inorganic matter and organic fraction of seston (f), and food availability were monitored monthly from January to December 1998. Feeding rates, including clearance rate, filtration, ingestion and absorption, and absorption efficiency were higher in summer and autumn and lower in winter. Pseudofaeces were produced but the preferential selection of organic materials by P. viridis was not concluded. Scope for growth in  July and October were higher than in February. Activities of digestive enzymes including amylase and cellulase in the digestive diverticula and crystalline style were high in May and July and lower in February and October and correlated with f. Faster growth rates obtained for P. viridis in Hong Kong's summer are considered a result of enhanced feeding and absorption at high temperatures and f values.

The filter feeding bivalves Mulinia edulis and Mytilus chilensis, were exposed to a broad spectrum of concentrations and qualities of seston in order to compare the results of filtration rates measured volumetrically and gravimetrically, by both the traditional clearance method of Coughlan (1969) and the biodeposits method. Filtration rates, measured gravimetrically by both methods, tended to give similar results for both species, increasing with increase in seston and with decrease in seston organic content. With volumetric measurements, the filtration rates for both species also increased with the concentration of seston, however, in Mulinia edulis, the effect of the organic content of the food was less than that observed using gravimetric units, which is seen in the smaller slope of the regression equation (TFRv=−0·49). In the case of Mytilus chilensis there was no verifiable effect of the quality of the food on the filtration rate when expressed on a volume basis. The filtration rates of Mulinia and Mytilus measured by two methods and two units showed a similar behaviour with increase in the concentration of seston.

The diet of all chaetognath species found in a broad pelagic area of the eastern Mediterranean was investigated through gut content analysis. Eight chaetognath species were recovered from four depth intervals between 0 to 300 m in the Ionian, Cretan and Rhodes Seas and in the Cretan Passage. The mean food containing ratio (FCR) value for all chaetognaths combined was 0·048. Copepods comprised nearly 65% of the total food items consumed. The epipelagic species Sagitta enflata, Sagitta serratodentata atlantica, Sagitta bipunctata and Sagitta minima fed mainly in the 0 to 50 m surface layer, while the mesopelagic species Sagitta lyra, Sagitta decipiens, Sagitta hexaptera and Krohnitta subtilis fed in deeper layers. Sagitta s. atlantica showed the highest mean FCR in the integrated water column (0 to 300 m) of the whole sampling area. The estimated impact of chaetognath predation on copepod communities ranged from 0·3 to 7·8% of the copepod standing stock, and was higher in the Ionian Sea and the Cretan Passage than in the Cretan and Rhodes Seas. Sagitta s. atlantica, S. lyra, and S. decipiens had the most important predation impact among the eight chaetognath species found in the 0 to 50 m, 50 to 100 m and 100 to 300 m depth layers respectively.