Reproductive phenology among temperate hermit crabs, reproductive seasons of nine sympatric species and some reproductive characteristics of four Pagurus species were investigated in Tosa Bay, southern Shikoku, Japan. Females of P. filholi, P. maculosus, P. minutus and P. nigrivittatus had clutches mainly in winter and were found to breed multiple clutches within each reproductive season while four Diogenidae species and P. japonicus mainly reproduced in summer, suggesting that interspecific variation in reproductive phenology of temperate hermit crabs might be determined by allopatric adaptation with phylogenic constraints. There was interspecific variation in the length of reproductive seasons among the four Pagurus species and the variation was considered to reflect the interspecific difference in the number of clutches per reproductive season, not in the ovigerous period per clutch. The length of reproductive seasons among the four species seemed to relate to maturity size and/or interspecific differences in thermal adaptation.

The mole crab Emerita talpoida occurs in the swash zone of sandy beaches. Although crabs move with the tide, field studies found that the smaller crabs are distributed higher intertidally than the larger crabs. The present study tested the hypothesis that the rhythm, timing of activity, and activity amplitude with respect to tides would be different among megalopae, juveniles, small females, small males, mature males and large ovigerous females and underlie the observed field distributions. Activity of individuals in columns was observed under constant conditions with a video system and quantified as the number of ascents from the sand each 0·5 h. All life history stages had a circatidal rhythm in vertical swimming with median free running period lengths near 12·4 h and activity peaks after the time of high tide. Period length and time of activity peaks did not differ significantly among the life history stages. Activity amplitude was related to tidal amplitude of consecutive high tides at the collection site. Larger crabs had greatest activity after the lower amplitude high tides whereas small crabs had equal activity amplitude on consecutive tides. The test hypothesis was partially supported because the difference in activity amplitude predicts an oscillation between overlapping distributions of small and large crabs after low amplitude high tides, with the smaller crabs distributed higher on the beach after high amplitude high tides. The rhythm was not affected by a light:dark cycle and could be entrained by mechanical agitation.

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.

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.

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 new mangrove barnacle, Fistulobalanus sumbawaensis sp. nov. from Sumbawa Island, Indonesia shares the common morphological characteristics with the subfamily Amphibalaninae in having a shell wall of six, porous compartmental plates; radii solid; alae not cleft; basis calcareous, tubiferous in single layer. This new species belongs to the genus Fistulobalanus mainly in having parietal tubes arranged in two or more rows; primary tubes with transverse septa; subsidiary tubes formed between the primary septum and outer lamina. In particular, the new species is similar to F. patelliformis in the shape of the shell, the transverse section of subsidiary tubes, the tergum and some characteristics of trophi and the cirri. However, this new species is easily distinguishable from all members of the genus Fistulobalanus in having no coloration or striations on the external surface of the shell, subsidiary tubes only appearing inside the ribbed part of the shell, and the scutum having a short adductor ridge.

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.

The morphology of burrows constructed by the upogebiid mud shrimps Austinogebia narutensis and Upogebia issaeffi was studied using resin castings of burrows in situ on Mukaishima Island, Seto Inland Sea, Japan, where the two species occurred sympatrically. The burrow structure of both shrimps is a relatively simple Y-shaped pattern, which is typical of the family Upogebiidae. Total burrow length, and length and overall width of the U-shaped section of A. narutensis were greater than those of U. issaeffi, possibly because A. narutensis is the larger species. When the ratios of the burrow measurements to the mean burrow diameter were compared to exclude possible size effects, the burrows of A. narutensis had a wider and shallower U-shaped section than those of U. issaeffi. Because the casts were made where the two species occurred sympatrically, the differences in the burrow morphology were not due to the differences in environmental factors but to the difference in the shrimp species, whether they are adaptive or not.

Two species of the genus of large gastropods Cymbium were observed on the tidal flats of the Banc d'Arguin, Mauritania: C. pepo and C. tritonis. Average densities on a flat studied in detail were 0·0009 and 0·0014 individuals per m2, respectively. Both species leave the tidal flats in April and are absent until at least September. Their density on the tidal flats was maximal on sandy sediments. Probably the distribution of their prey species determines the distribution of Cymbium. Prey species observed were the bivalves Anadara senilis (97%), and an occasional Solen vagina and Venerupis sp. The annual predation pressure of Cymbium on intertidal Anadara was estimated to be <1%.

Samples of Ostrea edulis were collected during 1999 and 2000 from five sites in Scotland, and from one site each in Northern Ireland, Ireland, France, The Netherlands and Norway. Samples were scored at four microsatellite loci. Mean numbers of alleles per locus varied from 12·6 to 16·6 and observed heterozygosity per locus ranged from 0·801 to 0·845. Samples derived originally from hatchery seed showed significantly fewer alleles per locus and significantly reduced expected heterozygosity compared with wild populations. However, observed heterozygosity did not differ significantly between the two groups. Significant deficiencies of heterozygotes were present at one or more loci in four of the ten populations sampled and a significant excess of heterozygotes was present at one locus in a hatchery-sourced Scottish population. Genetic distance indices revealed that the Norway population was the most distinct from all others and that hatchery-sourced populations were also relatively distinct from other wild populations. However, genetic subdivision was generally low implying high historical ‘migration’ rates for these populations.

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.

Calyptogena gallardoi sp. nov. is described from eight articulated and 15 separated valves collected by dredge at ∼760 m depth off the Bay of Concepción, central Chile (∼36°S). In general outline, C.gallardoi sp. nov. is close to C. pacifica and to a new species of Calyptogena from Peru, from which it differs in details of the shell shape and hinge margin. Bivalves of the genus Calyptogena are typical constituents of marine chemosynthesis-based communities, and are therefore indicators of reducing environments. In the area of occurrence, the presence of C. gallardoi sp. nov. is related to methane seepage, associated in turn with the extensive gas–hydrate fields recently reported for the Chilean margin along 35°S to 45°S. Gas-saturated sediments as well as fragments of other chemosynthetic endosymbiont-containing clams of the families Vesicomyidae, Lucinidae, Thyasiridae and Solemyidae were also retrieved in the area.

Calyptogena gallardoi sp. nov. is the first species of Calyptogena s.s. and the second species of the family Vesicomyidae so far described for the south-eastern Pacific area.

More than 127 specimens of the bivalve mollusc Idas simpsoni were collected from the skull of a fin whale Balaenoptera physalus. The skull was trawled up from a depth of 430 m near Mljet Island in the south Adriatic Sea. This is the first finding of I. simpsoni in the Adriatic Sea.

A new species of the genus Tambja is described from the western Atlantic on the coast of Brazil. To date, the genus Tambja was represented in the Atlantic Ocean by nine species but only three of them have been recorded from the western Atlantic: T. gratiosa from the Gulf of Mexico, T. divae from Brazil and T. oliva from the Caribbean coast of the Isthmus of Panama. Tambja stegosauriformis sp. nov. is easily distinguished from all its congeneric Atlantic species of the genus by having very well developed light blue tubercles scattered on the yellowish-orange ground with an elongate crest behind the gill until the end of the tail. The anterior margin of the notum is very wide and elevated and it extends into a kind of lapel around the rhinophores. This peculiar external morphology and its conspicuous coloration characterize this species.

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.

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.

Species of marine bivalve molluscs identified in the last nine years in the Greek waters have been used to update the checklist published in 1996 (Fauna Graeciae VII) by inserting necessary changes and adding new records. The updated version includes 13 new species among which three are exotics (non-Mediterranean species), five rare, two new deep sea and one previously considered a fossil species. Also, as a result of new resources, the distributions of pre-existing native molluscs have been updated to include new habitat areas. The nomenclature is also up to date based on the CLEMAM Database. Thus five species are now excluded either because they are junior synonyms of pre-existing valid species (2) or because of old spurious records (3 species). Additions and corrections of the 1996 checklist have resulted in a total of 308 bivalves in Greek waters.

The condition of three intertidal Paracentrotus lividus populations, which inhabit an area between Rabat and Casablanca (Morocco) known by its high wave energy and its substantial anthropogenic disturbances were described. The growth rate of the juvenile sea urchins in this intertidal zone was low compared with more sheltered populations. A sharp increase in the gonad index was observed between January and March at the beginning of a period of algal production, and was concomitant with increases in seawater temperature and food consumption rate. This gonad index increase was followed by a single spawning period occurring between March and June, probably triggered by the phytoplankton bloom induced by upwelling conditions. Larval development in all three populations was severely inhibited and could be explained, in part, by high and generalized Cu contamination throughout the region. Specific contamination of particular populations by Pb or Hg was attributed to local industries and the incomplete dispersion of pollutants in spite of the high hydrodynamics along the Moroccan Atlantic coast. One of the three populations studied showed strong indications of abnormal development; the degradation of its condition appeared to be due to the presence of a wadi (temporary river) which can seasonally reduce the salinity, directly affecting the sea urchin physiology and indirectly enhancing the metal toxicity.

A re-assessment of the rocky sublittoral biota at Hilsea Point Rock in south Devon, UK was undertaken 50 years after the first descriptive surveys. The overall appearance of the fauna and flora in 2003 was much as described in the 1950s but with some species not re-found in 2003 and some species added to the lists from the 1950s.

Colonies of the phlebobranch ascidian Perophora japonica were found in August 2003 in Humboldt Bay, northern California, growing on a submerged settling panel. This species has a unique terminal budding in addition to the usual subterminal stolonial budding: bright yellow stellate plaques form at the tips of many stolons. The plaques break off, float away and reattach, subsequently forming new stolons and new colonies. The presence of these plaques, and the larger size of the zooids, distinguish it from the native Perophora annectens. This is the first North American record for this species.