Macrofaunal assemblages inhabiting stable offshore muddy sand substrata responded predictably to the effects of mild organic enrichment arising from sewage-sludge disposal off the north-east coast of England (western North Sea). At the disposal site, densities were elevated up to two-fold, but classical ‘indicator’ species were only marginally enhanced and there was no evidence of a significant waste-induced change in assemblage structure. The response following cessation of disposal was equally predictable, with a decline in densities to ‘reference’ levels some three years later. However, physical manifestations of disposal, including tomato pips and non-biodegradable artefacts, were still evident after this time.

Changes in diversity at selected monitoring stations tended to track each other over time and the employment of treatment/reference ratios and limit values for acceptable change provided a useful model for the simplified expression of trends. Predictions concerning the limited scale and intensity of the effects of sewage-sludge disposal appear to have been met, indicating that the management option of sea disposal was, at the time, an environmentally acceptable one.

Temporal trends in the benthic fauna were also correlated with winter values of the North Atlantic Oscillation Index for the preceding year. The densities and variety of species tended to be lower in response to warmer winters characterized by westerly airflows which were commonly encountered in the 1990s. Finally, the increasing importance of extended time-series data for the investigation of man-made impacts on the marine environment is highlighted, along with the accompanying requirement for continuity and quality assurance of sampling programmes.

Mesozooplankton was sampled during one year in the eutrophicated Vranjic Basin and the influence of environmental variables on its abundance and distribution was analysed. Parallel microzooplankton samples were collected in order to assess trophic relationships within the zooplankton community. Total mesozooplankton abundances were high, exceeding 2×104 ind m−3 in the warmer part of the year, but the biodiversity was low. The annual variability of this assemblage was mostly influenced by temperature. Copepods were dominant among net plankton groups, while ciliates dominated the protozoan community. The key species of the copepod community were Acartia clausi, Oithona nana and Euterpina acutifrons, occurring simultaneously throughout the year. High abundances of small copepod Oithona nana were determined in both meso- and microzooplankton samples, and comparisons of the catches from 125 μm net and 5-l Niskin bottles revealed no significant differences between them. Significant correlation determined between Acartia clausi and oligotrich ciliates indicates predator–prey relationship and the importance of the ciliate community in the energy transfer through the trophic web of this area.

Phytopigment concentrations (chlorophyll-a and phaeopigments), labile organic matter (proteins, carbohydrates and lipids), bacterial density and frequency of dividing cells were analysed in the sediments of a large coastal area covering the southern Adriatic continental shelf between Italy and Albania in order to describe the trophic status of coastal marine sediments. On average, sediments of the Italian coast displayed the highest phytopigment and biopolymeric carbon concentrations compared to sediments of the Albanian coast and indicated an increased nutritional status of this coastal ecosystem. Different trophic conditions were evidenced in terms of biopolymeric composition of sedimentary organic matter as an increase in protein and a decrease in the carbohydrate contributions to total biopolymeric carbon was observed moving from the Albanian to the Italian coast. Using a benthic approach for the evaluation of trophic status shallow Italian sediments (0–50 m) were mainly classified as eutrophic and were subjected to stronger anthropogenic disturbance. This was particularly evident in areas in front of city harbours (Brindisi and Barletta) that were classified as hypertrophic and displayed the highest biopolymeric carbon (BPC) concentrations and protein to carbohydrate ratio (PRT:CHO on average >1). In contrast Albanian sediments as well as deeper Italian stations (>50 m), resulted mainly in meso-oligotrophic and displayed lower BPC and PRT:CHO ratio (on average <1). The study of bacterial variables provided an improved approach for the conceptual definition of trophic state using benthic biochemical measures. An inverse relationship occurred between the nutritional contents and the bacterial density within meso-oligotrophic sediments. This may reflect an increase in ecosystem organization and complexity (i.e. increased abundance of the higher trophic levels) which may determine a reduction of the bacterial density at increasing trophic conditions. In contrast a positive correlation was found within eutrophic and hypertrophic sediments suggesting that at high organic matter concentrations the ecosystem is no longer capable of further organization.

Four species of gymnamoebae isolated from a sandy shore were subjected to hydrodynamic disturbance within microcosms. Increasing the level of disturbance increased the generation times of all four isolates. Generation times of a small Platyamoeba sp. and a limax amoeba were least affected by increasing disturbance. The greatest increase in generation times was observed in populations of two large (>15 μm) Mayorella sp. and Vannella sp. This study shows that hydrodynamic disturbance may be an important community structuring force within natural marine amoebae communities.

Recent studies indicate that monothalamous (single-chambered) foraminifera are an important component of meiobenthic communities in the brackish, coastal waters of the Black Sea. The dominant taxa include Psammophaga and Vellaria, both of which are common in estuarine settings in other parts of the world. Here, we describe Tinogullmia lukyanovae sp. nov. from the Crimean and Caucasus regions of the Black Sea. The new species is several hundreds of microns in size. It is characterized by a more or less symmetrical, spindle-shaped to cylindrical, organic-walled test with two terminal apertural structures, usually in the form of rounded or more elongate, nipple-like projections. The protoplasm is finely granular and a nucleus is not visible. The new species typically occurs in well-oxygenated water at depths of a few tens of metres or less. A specimen from a 250-m deep site off the Caucasus coast, tentatively assigned to T. lukyanovae sp. nov., is of particular interest because it occurs at a depth where the bottom water is anoxic and sulphidic.

Between May of 2000 and July of 2001 a study aiming to determine the seasonal variation of syllid local population abundances was carried out. Samples were taken every second month and consisted of two replicates, each one being a quadrat 20 cm wide. After fixing, the samples were washed and the draining water was passed through a 1 mm sieve; then the syllids were identified and counted. For each replicate a number of ecological indexes were calculated, namely population density, number of species and Shannon's and Simpson's diversity indexes, computing mean values for each sample. In order to identify the most representative species of the taxocoenosis the Ci (constancy index, frequency of the species ranging from 0 to 1) and Di (dominance index, relative abundance ranging from 0 to 100 considering all the collected individuals) were computed for each one.

Analysis of the eight samples yielded 6548 individuals and 48 species belonging to the four subfamilies of Syllidae, of which Exogoninae and Syllinae were the most abundant and diverse. During the study period, the syllid taxocoenosis suffered dramatic changes. The abundance, that in May of 2000 was 33,375±775 individuals/m2, diminished to 2162.5±37.5 in September. After this date, the population density slowly increased. The number of present species evolved in a very similar way. Twelve species occurred in all the samples, although just six were abundant enough to yield Ci×Di products exceeding 5, thus being considered as good descriptors of the taxocoenosis. The variation of population density for most of these species more or less paralleled that of the total population of syllids. With regards to relative abundance, the taxocoenosis was always clearly dominated by Exogoninae species, especially by Salvatoria vieitezi, whose dominance scores always fluctuated around 45%. Syllis prolifera was the only important non-Exogoninae species in terms of dominance, although this parameter showed strong variation in this species.

Prionospio patagonica inhabits temporary silty tubes intertidally and shallow subtidally in brackish water estuarine environments in southern Chile. The species is gonochoristic with the female:male ratio being close to 2:1. Females and males release gametes into water. Pelagic planktotrophic larvae were caught in the plankton in the River Valdivia estuary in October–November and in March. Development of the adult morphology is described and illustrated beginning from the 2-chaetiger larval stage. One pair of lateral eyes first appears in the early larva, and shortly after that the right median eye develops. The left median eye appears after settlement, in juveniles with 10–11 segments. Developed 6-segment larvae have three dark red eyes, short palps of equal length, no nototrochs, one pair of small cells with grasping cilia on the pygidium, a small ciliated pit, gastrotrochs on segments 2–6, long serrated bristles in notopodia, adult capillaries in noto- and neuropodia on segments 2–5, single hooks in both rami on segment 6, and one pair of provisional papillae on the pygidium. A ventral buccal bulb is present below the short oesophagus and two pairs of provisional protonephridia are present in segments 1 and 2. The wall of the anterior part of the midgut has a characteristic brown pigment. The 6-segment larvae, about 400 μm long, settle and undergo gradual metamorphosis. In adults, hooks are gradually lost from noto- and neuropodia but sabre chaetae appear from segment 7 and retain their anterior position as growth proceeds. Up to 14 pairs of cirriform branchiae develop from segment 2, and three adult cirri appear on the pygidium. The afferent and efferent arms of each branchial blood loop are interconnected by capillary loops. A greenish heart body is present in the main dorsal blood vessel in anterior segments. Up to 21 pairs of metanephridia develop in anterior sterile segments, beginning with segment 4. Transparent gonoducts are present in fertile segments.

The need to use biomonitors representative of the sedimentary compartment has been recognized, particularly in estuaries. Thus, trace metal contamination has been monitored in an infaunal polychaete worm Nereis diversicolor and sediments in the Seine estuary and comparatively in the relatively clean Authie estuary (French coast of the English Channel) over two years taking samples every three months at both sites. No correlations were shown between total metal (Ag, Cd, Cu, Pb, Zn) concentrations in raw sediments and ragworms. Because these worms are known to be good biomonitors of the bioavailabilities of sedimentary trace metals, it follows that total sediment metal concentrations have a poor predictive ecotoxicological value. Using a correction factor to minimize the influence of weight, it is possible to make a good estimation of the average metal concentrations in a population of worms at a given site, sampling only a limited number of specimens. Metallothioneins are often considered to be good biomarkers of the presence of significant availabilities of trace metals. Metallothionein-like proteins (MTLPs) are present in N. diversicolor, but there is no significant relationship between MTLPs and metal concentrations. This situation might result from the importance of metal-containing granules, both extra- and intracellular, in ragworms.

Shells inhabited by hermit crabs are unique microhabitats with an abundant epi- and endofauna. Using polychaetes as an example, communities associated with the whelk Stramonita haemastoma, the hermit crabs Clibanarius erythropus and Calcinus tubularis, as well as empty, damaged shells were investigated. No polychaete community was associated with live S. haemastoma: only 30% of the investigated gastropods harboured polychaetes. Hermit crab-occupied shells supported polychaete communities dominated by Spirorbidae in the case of Clibanarius erythropus and by small Sabellidae, Spirobranchus polytrema and Dipolydora armata in Calcinus tubularis. The polychaete fauna associated with empty shells was similar to that on shells previously inhabited by one of the hermit crab species but different from those of the surrounding hard bottom. The reproductive strategy of the some polychaetes species is adapted to life on this small-sized habitat.

A detailed illustrated key to the identification of the European species of the genera Palaemon and Palaemonetes is provided. This key has been elaborated taking into account recent changes in the species composition of both genera for European waters, such as the invalidity of Palaemon garciacidi, which is a synonym of P. longirostris, and the presence of an introduced species, Palaemon macrodactylus that has been recently recorded at different localities along the Atlantic coast. The key is based on external morphological characters to facilitate its use by non-specialists. Data on the coloration, habitat and distribution of all species are also given.

Three species of the callianassid genus Nihonotrypaea occur in the Ariake Sound estuarine system, southern Japan; they consist of two tidal-flat species (N. harmandi; N. japonica) and one boulder-beach species (N. petalura), with maximum population densities of 1440, 343, and 12 ind m−2, respectively. Nihonotrypaea harmandi and N. petalura are distributed along the coastline from the outermost part of the sound to the open sea, while N. japonica occurs in the middle part of the sound. Nihonotrypaea japonica has an extended reproductive period from late winter to autumn, while those of the other species are from late spring or summer to autumn. Interspecific comparisons were made for recently laid egg size (as volume) and clutch size (as number of eggs per female). Only in N. japonica was a seasonal egg size variation observed, being significantly larger in winter to spring (mean=0.106 mm3) than in summer (0.080 mm3). By contrast, clutch size was significantly smaller in winter to spring, resulting in nearly the same clutch volume per female (product of the mean egg volume and clutch size) between the seasons. Among the three species, the egg size was ordered as N. japonica (overall mean volume through the seasons=0.092 mm3)>>N. petalura (0.057 mm3)>N. harmandi (0.054 mm3). The clutch size was ordered as N. harmandi>N. petalura≈N. japonica. The clutch volume was ordered as N. japonica≈N. harmandi>N. petalura. The smallest clutch volume value for N. petalura female showed an opposite trend to the relative size of the major cheliped found in a previous study.

Investigations were made on reproduction and population dynamics of Leptochela gracilis on the western coast of Korea, Yellow Sea, between May 2000 and October 2001. The egg volume was significantly larger at later egg stage than at early egg stage. Brood loss did not occur during the incubation period. Based on dry weight, the reproductive output (mass of incubating eggs/mass of female) averaged 0.18. The mature females first appeared in May, reached a peak in July and August, and then did not appear after September. The main breeding season was summer, although slightly different between the two years. A similar pattern could be found in monthly changes of gonadosomatic index (GSI), showing relatively higher GSI during the annual breeding season. A significant difference in ovarian dry weight between females with non-eyed eggs and eyed eggs indicates that ovarian maturation occurred during the embryonic development, suggesting that females were potentially consecutive breeders, capable of multiple spawning within a reproductive season. The size at which 50% of females were mature (CL50) was estimated as 7.63 mm carapace length. Females grew faster and reached a larger size at age than males (L∞=12.43 mm CL and K=0.90 y−1 for females, and L∞=12.22 mm CL and K=0.58 y−1 for males).

The present work reports the existence of extended parental care in a hermit crab species of the genus Calcinus. The species shows a high energetic investment in egg production, only producing one to six large-sized eggs. The larval development is extremely abbreviated, with the larvae hatching at an advanced zoeal stage, a rather uncommon feature among marine and non-symbiotic decapods. The sequential moults end in a glaucothoe-type larval stage that is retained inside the female's host gastropod shell, probably in complete lecithotrophy. The high maternal reproductive investment displayed by this species is certainly maximized through the retention of juveniles until they enter a suitable gastropod shell, since it considerably reduces the chances of intra- or interspecific predation.

Two types of alvinocaridid shrimp postlarvae were taken at plume depth over the Kairei and Edmond hydrothermal vent fields in the south-west Indian Ocean. These postlarvae were superficially indistinguishable from similar postlarvae taken previously over hydrothermal vents in the Atlantic. The micronekton invertebrate taxa in the water column over the Kairei and Edmond sites were similar to those in the Atlantic. The most frequently taken deep-water fish at Kairei was an unidentified cyemid snipe eel, whereas in the Atlantic its place was taken by Gonostoma bathyphilum and species of the melamphaeid Scopeloberyx. Previous sampling over East Pacific Rise hydrothermal sites at 13°N failed to take any alvinocaridid postlarvae, but the ostracod Gigantocypris agassizi was a major component of the micronekton.

The composition and spatial distribution of the mollusc fauna on the subtidal soft bottoms of the Ría de Aldán (Galicia, north-western Spain) were studied by means of quantitative sampling and multivariate analyses. The faunal distribution was mainly conditioned by a sedimentary gradient that was defined by a decreasing grain size from the mouth towards the inner margins of the ría. Several assemblages were determined which could be defined according to the classic terms of ‘community’ and ‘facies’. A ‘Venus fasciata community’ and a ‘facies of Goodallia triangularis–Pisione parapari’ are present in coarser sandy sediments of the outer ría area. The communities characterized by ‘Venus gallina’ and ‘Tellina fabula–Tellina tenuis’ were found in the fine sand bottoms at the centre and margins of the ría. The shallower and muddier sediments in the inner ría showed a mix of typical species from the ‘Abra alba’ and the ‘Venus gallina’ communities, and in the Río Aldán's mouth could be distinguished a facies of a protected zone.

Aspects of the feeding behaviour of Ergalatax contractus (Muricidae) were studied. Field experiments demonstrated that large numbers of individuals of this species, comprising ∼90% of a suite of gastropod scavengers, were attracted to baited traps in the subtidal sands of Lobster Bay, Cape d'Aguilar Marine Reserve, Hong Kong. Laboratory experiments identified the effective chemo-detection distances of E. contractus as 60 cm in still and >80 cm in flowing water, respectively. The average times to arrival at bait in still and flowing water were 92.3 and 69.0 min, respectively, but were significantly less for individuals experiencing a longer period of starvation. The mean time taken for E. contractus to consume a meal was 70.6 min.

Comparisons were made between Ergalatax contractus and Nassarius nodifer, representative of a suite of sympatric scavenging nassariids in Lobster Bay. The nassariid arrived significantly faster at bait in both still (30.2 min) and flowing water (20.8 min) than E. contractus and fed faster (25.7 min), as is typical of representatives of the Nassariidae. Although the two species partition carrion resources temporally, manipulation experiments provided evidence for inter-specific competition between them. That is, although E. contractus possesses the morphological and behavioural characteristics of a predator, its opportunistic scavenging abilities have led to its success and numerical superiority on the shallow subtidal sands of Lobster Bay. The dominance of E. contractus in Lobster Bay, and elsewhere in Hong Kong, is unusual. Here, the normally predatory E. contractus, far outnumbers all other scavengers, possibly because of an enhanced, largely allochthonous, supply of food which it is able to exploit by virtue of its previously identified opportunistic habit of scavenging the leftovers of other predators. The presence of inter-specific competition between E. contractus and a sympatric suite of nassariids enhances, not impedes, carrion exploitation.

Ostrea edulis was extremely rare in the wild in Strangford Lough from the early 1900s until renewed spatfall was observed at a number of sites in the 1990s. A monitoring programme was undertaken to investigate the presence and distribution of planktonic oyster larvae at nine sites around the lough between June and September in 1997 and 1998 as a precursor to studies of spatfall patterns. Larval densities at sites in the northern basin of the lough were significantly higher than those in the southern basin where larvae were lacking or in low numbers. Densities and sizes of oyster larvae showed significant temporal variation suggesting pulsed larval release. Larval densities also showed significant spatial variation with higher densities at sites closer to commercial stocks pointing to these as the main source of oyster larvae. This hypothesis was supported during a larval flux study over a complete tidal cycle which indicated a 90% net tidal movement of O. edulis larvae from the entrance of the bay where commercial stocks were held to the main body of the lough. Thus the maintenance of dense commercial stocks of flat oysters may provide the key to the redevelopment of native oyster beds in Strangford Lough and elsewhere by providing an initial broodstock nucleus from which larvae can be exported.

Direct observations of sex change were made on Patella vulgata, which has long been considered a protandrous hermaphrodite based on indirect methods. Thirty per cent of the male limpets that were marked during the spawning season in 2003 were female when they were re-examined during the spawning season in 2004. This confirms that protandry does occur within the superfamily Patellidae.

A review of existing literature records of echinoderms from Malta and a study of a large collection of specimens was carried out between 2000 and 2004 so as to update and produce a validated checklist of echinoderms occurring in Maltese waters. Seventy different species of echinoderms are recorded, including a number of species for which only single records exist for the Maltese islands and five species that were not found in the present study. The Maltese echinoderm fauna includes 45% of the 153 recorded Mediterranean echinoderm species, and apart from two aliens, is typical of the central Mediterranean region.

Time-lapse video was used to record movement paths of Strongylocentrotus droebachiensis on a rocky bottom at 8 m depth, both at a grazing front and in recently formed barrens in the wake of the front. Urchins did not exhibit strong directionality in movement and we did not detect any differences in movement variables between the front and barrens. Density of conspecifics had a negative effect on the speed, move length (distance), and daily displacement of urchins, but did not significantly affect the proportion of time spent moving, the linearity index and the number of moves taken per day. The frequency distributions of turning angles between moves and steps were non-uniformly distributed, indicating directionality in individual paths. A correlated random walk model was used to predict the displacement of urchins through time and provided a good fit with observed data. Our results provide insight into the foraging behaviour of S. droebachiensis and are consistent with previous observations of small-scale movement in this species.