One specimen of African threadfish was caught near Split (middle Adriatic) on 26 September 1973 and donated to the Museo Storia Naturale di Genova (MSNG). Tortonese reported on the extralimital capture of this species (under the name Scyris alexandrina) without any other data. This was neglected and this species was not put in the list of Adriatic fish. After revision of the specimen and data from the MSNG it could be suggested that the species must be in the list of Adriatic fish. This record represents the northernmost occurrence of this species in the world.

The general composition and abundance of microalgae in sediment, water column and stomach contents of scallops were studied at two Euvola ziczac beds on the south-eastern inner Brazilian continental shelf. These areas, which support an extensive demersal fishery, are hydrologically dominated by Tropical and Subantarctic Waters and exhibit a summer water intrusion of South Atlantic Central Water (SACW). The same genera of benthic diatoms, mainly <30 μmm, were found on sediment and scallop stomach samples. Despite the seasonal variation of hydrographic conditions, the composition and abundance of main benthic diatoms from sediment and stomachs did not change throughout the year. On the other hand, phytoplankton from the water samples collected above the seabed (mainly pelagic diatoms >30 μm and dinoflagellates) was composed of distinct taxa and presented a high seasonal variation in abundance. The prevalence of microphytobenthos in the scallop diet suggests the importance of this community to the sustainability of this valuable demersal fishery resource.

During the 2002 Antarctic Deep-sea Biodiversity (ANDEEP) programme to the Drake Passage, Weddell Sea Basin and South Sandwich Slope and trench, a new deep-water species of orbiniid polychaete was collected: Orbiniella andeepia sp. nov. Orbiniella andeepia appears to be most closely related to O. marionensis but differs in capillary setal structure, the type and number of acicular spines found in each podial lobe. Orbiniella andeepia is only the third deep-water species of Orbiniella to be discovered. It exhibits both a wide depth- and geographic-range within the Antarctic slope and abyssal sediments.

Larvae of Ibla cumingi from Daya Bay, China were cultured in the laboratory. Larval development includes six naupliar stages and a non-feeding cypris stage following the ground patterns of cirripeds. Larvae reached the cypris stage in nine days at ∼25°C after hatching. Morphological features including the cephalic shield, frontal horns, labrum, abdominal process, antennules, antennae and mandibles in all nauplii were described and illustrated using light microscopy. A full morphological description of cyprid larvae was provided using scanning electron microscopy. Attempts were made to compare the difference between the larval development model of I. cumingi and that of Ibla species.

Larval development of the parasitic barnacle Heterosaccus papillosus (Cirripedia: Rhizocephala: Sacculinidae) is described from larvae reared in the laboratory. Lecithotrophic nauplii of H. papillosus reached the cypris stage in 3·5 days, at 22–23°C. The development included five naupliar and the single cypris stage, thus following the typical pattern in the Rhizocephala Kentrogonida. Like the nauplii of all sacculinids, those of H. papillosus had a single pigmented nauplius eye, unsegmented frontolateral horns each with two long spines and a tubercle between the furcal rami, but they lack a flotation collar and have no seta on the antennal basipod. The male larvae are larger than female ones, the mean lengths in the two sexes never overlap. The most interesting feature of this species are the morphological differences between the male and female larvae. In the male nauplii III to V the anterior body margin is noticeably convex, that is not characteristic for female larvae. The male cyprid also has a more acuited anterior region, whereas that of the female is rounded.

The shell morphology of mud snails, Zeacumantus subcarinatus, both uninfected and infected by trematodes, was compared to determine if different trematode species induce different degrees of alteration in host shell shape. Snails harbouring either the echinostomatid Acanthoparyphium sp., or a double infection by the microphallid Maritrema novaezealandensis and an undescribed philophthalmid species, had a wider shell base relative to the rest of the shell spire, than uninfected snails or snails infected by only one of the latter two trematode species. These results are independent of any differences in shell length among the different infection groups. The findings of this study suggest that alterations in host shell morphology are species-specific trematode manipulations of host phenotype rather than a generalized host response to castrating trematodes.

Norway lobster (Nephrops norvegicus) larvae have been investigated in northern European waters, particularly in the Irish Sea where biomass estimation studies are used for the annual larval production method. However, nothing is known of their distribution in southern European waters, off the Portuguese coast or in the Mediterranean Sea. From zooplankton sampling off the Portuguese coast between October 1986 and March 2001, planktonic larvae of this species were known to occur from January to April off the north-west and south coasts. In the north, larvae were only observed over the shelf, shoreward of the upper limit of the adults' distribution. Larvae were never collected off the south-west coast of Portugal, even though this is one of the largest fishing grounds for this species off the Iberian Peninsula. The absence of larvae from all surveys in this region may relate to the local oceanographic conditions and shelf width.

A feeding frenzy of 12 octopuses of Vulcanoctopus hydrothermalis was observed from the manned submersible ‘Alvin’ at Parigo, a 2620 m deep hydrothermal vent on the East Pacific Rise. The aggregated benthic octopuses at the active vent used their arms and webs to forage on bathypelagic amphipods, apparently targeting their attacks based on contact with the swarming amphipods. Individual octopuses wrapped their arms around the mantles of smaller octopuses, apparently in competition for prey. Although members of the prey species, Halice hesmonectes, are individually small (<5 mm long), the density of their swarms may make them attractive prey for the octopus. Inactive sulphide spires encircled part of this vent site; octopuses that climbed these spires had easy access to the dense prey swarms. The presence of the spires may uniquely enable this site to support simultaneous foraging by large numbers of octopuses.

Reproductive patterns such as gonad maturation, production and release of gametes, fecundity and moulting play a major role in the continuity of populations and their adaptations to the environment they inhabit. The present study assesses the breeding cycle, moult activity and egg production in the hairy crab Pilumnus vespertilio, a typical inhabitant of intertidal pebble and rocky substrates of East African coasts. A total of 930 crabs was collected between January and December 2002 at Inhaca Island, southern Mozambique. Both oogenesis and spermatogenesis exhibit a continuous and synchronized pattern. Maturation of the female and male gonads occurs from early winter to mid summer and spawning is in summer. Moulting females showed two major peaks (January–March and October–December) whereas a single peak was recorded in males (October–December). Pilumnus vespertilio breeds continuously with high incidence in March and December and a strong decrease from April to July. Results revealed that both temperature and rainfall were positively associated with the relative abundance of egg-bearing females. The number of eggs carried by ovigerous females increased with size, ranging from 300 to 8000. The high reproductive activity of P. vespertilio may enhance larval survival and development, which guarantees juvenile recruitment in the study area.

Microzooplankton community composition, abundance, biomass and grazing impact were assessed, along with measurements of ciliate growth and mortality, during the onset of the spring bloom in the north-east Atlantic. The study was undertaken as part of the UK Biogeochemical Ocean Flux Study during 1 May to 15 June 1990. The microzooplankton community was composed of protozoans and metazoan developmental stages with respective mixed-layer depth integrated biomass values ranging from 127 to 638 and 74 to 394 mg C m−2. High numbers of aloricate ciliates (up to 35,000 cells l−1) dominated the microzooplankton community during early May prior to the onset of the spring bloom. Ciliate abundance then declined rapidly during mid-May with community growth rates ranging from −0·71 to 0·23 d−1. High abundances of metazoplankton (up to 400 l−1) were also recorded at this time and may have contributed to the decline in ciliate numbers. In late May and early June the protozoan community comprised a more even mix of dinoflagellates, tintinnids and aloricate ciliates. Phytoplankton mortality rates, measured using a dilution technique, ranged from 0·2 to 0·5 d−1. The microzooplankton consumed 8 to 44 μg C l−1 d−1, equivalent to between 16 and 40% of the chlorophyll biomass and 38 and 154% of primary production. These high rates of herbivory reflect the predominance of small (<5 μm in length) phytoplankton cells present throughout the first half of the study and support previous studies demonstrating the microzooplankton to be the main grazers of phytoplankton in the north-east Atlantic. However, there is also evidence that a disparity between predator and prey may have prevented a response by the microzooplankton to rapid increases in phytoplankton biomass and production during the spring bloom.

Libidoclaea granaria was collected as part of the by-catch of the Zygochlamys patagonica (Bivalvia: Pectinidae) fishery, between 36° and 39°40′S and at 80 to 128 m depth. Crab densities ranged from 0 to 150 individuals 100 m−2, with a mean of 9·8±20·4 individuals 100 m−2. Mature males and females ranged from 24 to 61 mm, and from 16 to 48 mm, carapace width (CW), respectively. The largest immature female measured 22·5 mm CW. The number of eggs carried by a female ranged from 1200 to 9300. Sponges were the most frequent epizoic organisms, followed by the lepadomorph cirriped Ornatoscalpellum gibberum, Serpulidae and Spirorbidae worms. Since all these organisms were reported on Z. patagonica beds, crabs are camouflaged to match their habitat. Small crabs usually had naked carapaces, indicating a high moult frequency. Larger crabs instead, had epibionts on their carapaces, suggesting a lesser moult frequency. The erosion of carapace spines and the heavy epibiosis of large specimens suggest the existence of a terminal anecdysis.

In the north-east Atlantic, the dominant reef-framework forming coral species, Lophelia pertusa and Madrepora oculata, form a symbiotic association with the polychaete worm Eunice norvegica. The polychaete–coral symbiosis was studied by visually observing and photographing live animals in aquaria over many months and using time-lapse video under infra-red lighting to record activity patterns. The polychaetes act as reef aggregating agents by joining coral colonies and enhancing the development of reef patches in deep water. The symbiosis was investigated using samples collected from a relatively shallow site in a Norwegian fjord and from a deeper open ocean site in the Porcupine Seabight. The potential functional roles of this symbiosis are considered. The reef aggregating behaviour of the polychaete symbiont allied with the ability of the coral host to anastomose its branches, the polychaete tubes and debris falling onto the reef structure will help to shift the balance between reef growth and (bio)erosion in favour of growth.

Phytoplankton blooms are known to influence barnacle recruitment and in boreal regions spring blooms work as an important trigger. Close to the west coast of the sub-continent of India, blooms tend to be triggered by breaks in the monsoon and the recurrence of the monsoon after a short break can stress the new recruits. The recruitment of Balanus amphitrite, an acorn barnacle, at Dona Paula Bay at the mouth of Zuari estuary, Goa, India was studied. Observations included variations in recruitment, larval abundance, development and reproduction. Adult conditioning and inter-brood variations were important factors in the larval ecology of this organism. The results indicate that the impulsive release of larvae during breaks between monsoons could be a short-sighted luxury for Balanus amphitrite in these waters. Temporal variations or recruitment failure in such environments can be attributed to inappropriate cue synchronization.

Ophelia bicornis sensu lato is a polychaete living in intertidal sandy habitats of Mediterranean and European Atlantic coasts, whose systematics have been strongly debated in the past few decades. In the present work the count of nephridiopores was coupled with genetic analysis carried out with DNA markers (inter simple sequence repeats) for a total of 30 individuals collected at six Italian beaches. Exact test, analysis of molecular variance, non-metric multidimensional scaling and assignment tests clearly separated individuals with five nephridiopore pairs from those with six pairs. This finding validated results of a recent allozyme study in which O. bicornis sensu lato was split into O. bicornis sensu stricto (six nephridiopore pairs) and O. barquii (five nephridiopore pairs). This paper represents a further contribution to the estimation of biodiversity within marine invertebrates.

Sphaerotylus antarcticus is a common Antarctic sponge characterized by a dense spicule fur that covers its surface. This sponge has been sampled at Terra Nova Bay from 22 November 2001 to 29 January 2002 at weekly intervals. On its spicules, a rich assemblage of benthic diatoms has been observed, mainly composed of Hyalodiscus sp., a centric sessile diatom, forming short colonies. The temporal trend of the abundances of these diatoms showed a maximum of 115×106 cells g−1 dry weight (dw) at the end of December. Almost all the diatom frustules observed in the sponge choanosome belonged to the planktonic species Fragilariopsis curta, which displayed a peak (50×106 cells g−1 dw) in the second half of January. Diatoms that were observed in the choanosome were of a size comparable to that of the inhalant pores, suggesting that sponges actively engulf diatoms, due to the pumping activity of their choanocyte chambers. Sponges, as active filter feeders, therefore represent one important vector in the transfer of energy from planktonic to benthic trophic chains in Antarctic habitats.