The behaviour of two ectosymbiotic animals, Peregrinamor ohshimai (a bivalve attached to the ventral cephalothorax of the host), and Phyllodurus sp. (a bopyrid isopod attached to the second pleopod of the host), during ecdyses of the host thalassinidean Upogebia shrimps was studied by time-lapse video of infested shrimps. In the intermoult stages of the hosts, both ectosymbionts did not move. However they moved on to the newly emerged body of the host at the time when the host moulted. Peregrinamor ohshimai began to move just after the host started moulting, whereas Phyllodurus sp. moved prior to ecdysis of the host and waited near the fissure from which the newly moulted body emerges first. There are highly correlated morphological relationships between the symbionts and the hosts. It is suggested that both ectosymbionts grow with the same host individuals after infection, keeping morphological affinity with their hosts without being discarded during ecdyses of the hosts.

The stomachs of 427 giant red shrimps, Aristaeomorpha foliacea, caught in the Strait of Sicily (Mediterranean Sea) during four seasonal surveys contained 73 cephalopods, or 8·6% of prey. Cephalopods ranked third as prey following crustaceans (49·2% of prey) and bony fish (20·5% of prey). The following cephalopod taxa were identified: Heteroteuthis dispar, Sepietta oweniana, Brachioteuthis sp., Abraliopsis morisii, Onychoteuthis banksii, Ancistroteuthis lichtensteinii, Histioteuthis bonnellii, H. reversa, Taoniinae sp., Octopodidae sp.; the dominant species was Heteroteuthis dispar (13 specimens). All remains pertained to small and very small specimens, including early juveniles; rostral length of 13 beaks (=17·8% of cephalopods) measured <1 mm. Early juveniles were found in stomach contents only in summer and winter. Cephalopod size was found to be positively correlated to shrimp size. No seasonal nor predator sex-related differences were found in the quantities and frequencies of ingested cephalopods.

This study was aimed at understanding the diet and the digestive function of the deep-living Lophogastrida species Lophogaster typicus (Mysidacea: Lophogastrida). Scanning electron microscopy (SEM) investigations have revealed that the mandibles exhibit typical features of a carnivorous diet, i.e. large and sharp incisor process and small molar one with only few scales. The analysis of gut contents confirms morphological data as crustacean remains have been recognized. However, the presence of a large quantity of unidentifiable soft particulate matter also indicates a saprophagous tendency. The external asymmetrical edge of the labrum consists of a small grinding area. The entire external face of the labrum exhibits numerous pores, which are related with glandular units. These units are organized into acini of two to four large cells. Two types of acini have been observed, i.e. with dark or clear cells. According to ultrastructural and cytochemical data, labral secretions are believed to be mucopolysaccharidic (for clear acini) and enzymatic components (for dark acini), and are therefore involved both in coating and in digesting the food. Moreover, presence of neuronal endings and endocrine cells, both associated with glandular units, and comparison between glandular units in starved and fed animals suggest a controlled release of the secretions. Therefore, the labrum plays a crucial role in the digestive function of the lophogastrid crustacean L. typicus, as it involves both mechanical and chemical breakdown of the food.

Squid of the genus Alloteuthis from the Aegean Sea and eastern Mediterranean were identified as A. media. It is not possible to distinguish A. media from A. subulata by relative fin length. Both ‘species’ are probably intraspecific forms. Egg size varied from 1·5 to 2·3 mm. Oocyte maturation in the ovary occurs in batches. The potential fecundity is some 1000–4000 eggs, most of these being released during continuous spawning accompanied by female growth.

Adults of the isopod Paragnathia formica inhabit burrows in saltmarsh banks from which they release larvae during autumn high tides. Larvae pass through three moult stages, each of which feeds ectoparasitically on estuarine fish (including Pomatoschistus microps), before a final moult to a non-feeding adult stage. The entire energetic reserves for survival and reproduction up to nine months (females) or 16 months (males) later are therefore acquired during these three brief periods of parasitism. Application of a plankton sampling technique showed larval density in the water to vary considerably between successive high tides. High densities of larvae (1 per 1·2 l) occurred on only one tide during a week-long study, when a corresponding peak in parasite prevalence in the fish population (10%) was recorded. Peak larval release was observed as the tide rose, at a time when host fish have been reported to be in greatest abundance. Considerable larval longevity was demonstrated in the laboratory in the absence of food (mean=43 d). Data are interpreted, in conjunction with field observations, in relation to larval parasitism opportunities post-birth.

The location and orientation of epizooic barnacles on the surface of their host is crucially important to the survival and growth of the animal and is determined at the time of settlement by the cyprid larva. The present study examines the location and orientation of Chelonibia patula barnacles on the upper surface of the carapace of the crab Portunus pelagicus from the Mediterrannean coast of Israel. Cirral activity behaviour patterns, such as turning angles of the cirral fan, types of cirral motion, and beat duration were determined with respect to the angular deviation of the rostro-carinal axis (RCA) of the barnacles from the direction of the incoming flow. While small barnacles (up to 1 cm rostro-carinal length) perform normal feeding beats and turn the cirral fan towards the incoming flow at all angles up to 180°, larger barnacles (>1 cm rostro-carinal length) do not extend their cirri when oriented at RCA angles exceeding 120°. Nearly all the sampled barnacles are oriented on the carapace at RCA angles of no more than 120° with respect to the anterior margin of the host crab, which is the predominant direction of incoming flow and food. It is concluded that larval choice of orientation at settlement is determined according to the direction of the current and the anticipated food-gathering ability of the adult barnacle.

An investigation of the oil spill after the wreck of the tanker ‘Erika’ on 16 December 1999 showed that the maritime area around the town of Le Croisic (between the Vilaine and Loire river estuaries) was severely contaminated by the resulting black tide. Samples of sediment, oil and water were collected during several missions to the Le Croisic headland and analysed. The toxicity of the oil was tested on two organisms, the harpacticoid copepod Tigriopus brevicornis and the alga Enteromorpha intestinalis. The tests showed only slight degradation of the oil after three months. In laboratory conditions, the toxicity of the sediment contaminated by the oil was apparent on the copepod after four days of exposure. Seawater in contact with the oil also had an effect on the alga.

This study employed a suite of three biomonitors to investigate trace metal pollution in the Thames estuary, a region of significant clean-up of contaminants and the cumulative return of fauna and flora over the last two decades. The biomonitors chosen are the brown seaweed Fucus vesiculosus (bladder wrack), the barnacle Balanus improvisus and the talitrid amphipod crustacean Orchestia gammarellus, in order to obtain data on the bioavailabilities of Zn, Cu, Cd, Pb, Fe, Ag and Mn in the Thames estuary in 2001, as a basis for future comparisons as pollution is further reduced in the Thames. Accumulated metal concentrations in these organisms represent integrated records of the total bioavailabilities of the metals to that organism at that location over a previous time period, and comparisons of accumulated concentrations in a biomonitor between sites are indeed comparisons of the recent contaminant bioavailabilities to that biomonitor. All three biomonitors showed geographical differences in trace metal bioavailabilities along the Thames estuary. There was general agreement in the conclusions to be drawn from each of the three species used. Raised bioavailabilities of zinc, cadmium, lead, iron and manganese are present, particularly in the middle region of the Thames investigated, downstream of the effluent discharges of the sewage works at Beckton and Crossness.

The qualitative and quantitative monthly composition and the annual temporal changes in a shallow (3·3–6·3 m) community of Crustacea: Decapoda associated with soft bottoms (very fine–muddy sand) and the seaweed Caulerpa prolifera in the south of Spain (Valdelagrana Beach in the Bay of Cadiz) has been studied for two years from February 1994 to January 1996. This community showed a similar pattern in both analysed cycles and could be characterized by a change or succession in the abundances of two groups of species: in autumn–winter Hippolyte inermis and Hippolyte varians (species associated with seaweeds); and in spring–summer: Philocheras monacanthus, Diogenes pugilator (characteristic of sandy bottoms) and Macropodia parva. The results of the ordination analysis of monthly samples is related to the absence or abundance of these dominant species although it does not define the two seasonal groups. The analysis of monthly richness, equitability, diversity and k-dominance curves, during the two years, showed a stable and rich community (with more than 6100 specimens caught belonging to 49 species) despite the human influence and the proximity of the Guadalete River.

The population dynamics of the shore crab Pachygrapsus marmoratus was studied at two different rocky shores, Cabo Raso and Avencas, within the central Portuguese coast. The population structure at these shores, obtained by pooling monthly samples, revealed marked discrepancies. Unimodal, right-skewed size–frequency distributions at Avencas contrasts with the bimodal distributions obtained at Cabo Raso, corresponding to early recruits and larger adults. Recruitment timing and intensity together with habitat complexity are probable causes of the differences observed. At Cabo Raso an intense recruitment season was recorded from September to November, but very small juveniles were always present in samples. Monthly polymodal distributions are apparent but the size structure too complex to identify age groups through the sampling period. At Avencas, the influx of new juveniles is temporally restricted and year groups recognizable from main recruitment events taking place around October. Young-of-the-year crabs grow quickly to mature size and join the reproductive stock in the next breeding season from late March to early September in the study region. The growth pattern in both sexes follows a seasonal trend with minimum growth during the breeding months and maximum growth rates from late winter to early spring. Life span may reach four years, probably more in males. At Avencas, population maintenance seems to be highly dependent on favourable conditions promoting adequate settlement intensity and timing. Early recruitment is presumed to enhance the reproductive output of young-of-the-year individuals which comprise the bulk of breeding crabs. At Cabo Raso settlement rates are much higher and recruitment timing may be less critical since most breeding crabs belong to the 1-y+ class.

The distribution of the recently discovered association of the parasitic isopod Ceratothoa steindachneri (Isopoda: Cymothoidae) with the lesser weever fish (Echiichthys vipera) is reported. Ceratothoa steindachneri appears to have colonized the south-west coast of the UK between the 1960s and the 1980s, possibly as a result of range expansion due to climate change. The occurrence of C. steindachneri in E. vipera from Arcachon, France, indicates that this association has been occurring for over 100 years. Our data confirm that C. steindachneri is able to parasitize a broad range of fish hosts.

Published and unpublished records of epipelagic calycophoran siphonophores from around southern Africa were examined for zoogeographic structure. There is a close match between prevailing patterns of surface ocean circulation and zoogeography, which while similar to previous studies of intertidal taxa and euphausiids, is different from them in some key details. Separate subtropical provinces are associated with both the Angola and Agulhas Currents, and the latter system has a marked influence on the composition of (warm-temperate) assemblages along the south coast of South Africa. The nearshore waters in the Benguela upwelling ecosystem (cold temperate) are distinct, but the Lüderitz upwelling cell does not appear to act as an internal boundary within the Benguela ecosystem, as has been previously noted for benthic communities. Species richness is greater in oceanic than coastal waters, and peaks in subtropical waters. High diversity is also noted offshore in the area between Capes Agulhas and Columbine, where water of Indian, Southern and Atlantic Ocean interact. Indicator species for each major water mass were tentatively identified.

Munida subrugosa was sampled monthly from November 1997 to November 1999 in the Beagle Channel by means of an epibenthic trawl. The reproductive cycle started in May, reflected by the occurrence of ovigerous females. Maximum size of oocytes, maximum value of gonadosomatic index in females (16·8 g mm carapace length [CL]−1) and males (1·6 g mm CL−1), and the proportion (∼70%) of ovigerous females with full egg-clutches occurred in June. Since the proportion of ovigerous females in October was ∼5% and the planktonic larvae reportedly hatch in September, the embryonic development lasted ∼90–120 days. Females and males attained physiological maturity at 9·9 and 8·0 mm CL respectively, and males reached morphometric maturity at 24·4 mm CL. Fecundity was correlated with female size (r=0·85) and was between 124 and 10,750 eggs per female. Average diameter of recently extruded eggs was 0·69 mm (SD±0·06 mm). At the beginning of the reproductive cycle, ovigerous females had partial broods of ∼300 eggs, which represented <5% of complete clutch.

Aspects of the population dynamics of the undulate ray, Raja undulata (Chondrichthyes: Rajidae), one of the more abundant elasmobranch fish captured along the Portuguese south coast (Algarve), were studied for the first time. Some traditional elasmobranch vertebral enhancing techniques were compared and the most precise for this species determined to be the cedar wood oil immersion and the alizarin red S stain. The sample consisted of 14 age-classes, with age-classes 3 to 8 being the most represented. Evidence of an annual deposition pattern of a pair of bands (one opaque and one translucent) was found by marginal increment analyses. Von Bertalanffy growth parameters were estimated and no differences found between males and females (all data: Linf=110·22 cm, K=0·11 y−1 and t0=−1·58 y).

The shell selection and utilization patterns of three sympatric hermit crab populations (Clibanarius antillensis, C. sclopetarius, and C. vittatus) and shell availability were studied in a tropical intertidal low energy area. Shell availability (except for C. antillensis) was low and the hermit crabs showed overlap in size (mainly C. sclopetarius and C. vittatus). The influence of shell availability and selection on shell use was dependent on crab species. Clibanarius antillensis used mainly shells of Cerithium atratum, the most available shell species, while Clibanarius sclopetarius and C. vittatus occupied shells with lower availability in the studied area such as Chicoreus senegalensis, Stramonita haemastoma, Leucozonia nassa and Cymatium parthenopeum. The three species selected different gastropod shells with only Clibanarius antillensis using almost exclusively its preferred shell species in nature. The relationship between shield length and the weight of the used shell was not dependent on crab species or shell species, indicating that the size (not species) of the shells defines what size (not species) of crabs will occupy them.

The recent establishment of the lessepsian species Leonnates persicus (Annelida: Polychaeta: Nereididae) in Izmir Bay (Aegean Sea) was investigated. A total of four specimens were collected at three stations in December 2001, with two specimens having eggs within their coelomic cavities and parapodia. A re-description of the species together with its ecological and distributional aspects are provided.

A new species of Hirondellea was trapped in large numbers (N=441) in the Atacama Trench (Pacific Ocean) at 7800 m depth. The species accounted for 47% of the total number of amphipods collected and was the second most abundant amphipod after Eurythenes gryllus. Adult males and females reached maximum lengths of 13·5 and 14·1 mm. Length–frequency histograms showed no clear evidence of growth classes, but instars could be determined by using a combination of morphological criteria and size–frequency data. Growth factors based on mean lengths of successive instars ranged from 1·09 to 1·24 except at moults immediately prior to maturity when factors were in the range 1·02–1·04. Females moult from the pre-adult to the adult instar, without body growth. Moulting modalities of immature males are unclear. Equations obtained from regression analysis between wet weight and total body length indicate an allometric growth. Females grow at a rate of 10% higher than males, and both females and males display growth rates lower than those observed for juveniles, but growth increments at each instar of females are not significantly higher than those of males. The relationship between total body length (L) and wet weight (W) of all instars of Hirondellea sp. nov. is expressed by the power curve W=0·012 L3·279 (W in mg and L in mm).

This study was conducted between January and December 1995 at Armação do Itapocoroy, Penha, Santa Catarina, southern Brazil. Monthly samples were carried out in the morning, afternoon, and evening using two over-trawls with 6 m at the opening, 3·0-cm mesh at the outer part and 2·0-cm mesh in the bag. Dardanus insignis was collected year round but with higher densities in September and October. The hermit crabs were more abundant during the evening than the afternoon but no differences were recorded between morning and both evening and afternoon. Females were slightly more abundant than males but the sex ratio did not differ from 1:1. Females were more abundant in the smallest size-classes (<1·8 cm) while males outnumbered females in the largest ones (>2·2 cm). The individuals of this population of D. insignis have a mean cephalothoracic length of 1·89±0·40 cm (range 1·00 to 3·90 cm) and a mean weight of 40·26±27·06 g. The size distribution showed an unimodal pattern, with males being larger than ovigerous females, which, in turn, were larger than non-ovigerous females. Dardanus insignis showed a seasonal reproductive pattern with a peak from September to November and complete absence of ovigerous females from April to August. The von Bertalanffy growth function (VBGF) with temporal oscillation fitted for this population of D. insignis had the following parameters: L∞=4·40 cm, K=0·60, C=0·95, WP=0·35. Recruitment was estimated to start in September and was extended to the following months. Estimates of longevity ranged from 20 to 62 months. A mortality rate of 2·21 was estimated based on the length converted catch curve. The cephalothoracic length of males and females showed, respectively, positive and negative allometry with both cephalothoracic width and crab weight.

The habitat and feeding preference of two gastropod mesoherbivore species, Ansates (Helcion) pellucida and Lacuna vincta, inhabiting the kelp Laminaria hyperborea were investigated by studying the distribution, habitat choice and food preference of the herbivores between new and old kelp fronds. Nitrogen content and chemical defence (phlorotannin) level of the kelp fronds were measured in order to determine whether they were correlated with the feeding preference of the herbivores. The habitat choice of Lacuna vincta was correlated with the food preference of this species, while the habitat choice of A. pellucida probably was due to some other factor, e.g. competition or mortality. Ansates pellucida preferred to reside on the old fronds of Laminaria hyperborea, but consumed an equal amount of both tissue types. Lacuna vincta, however, preferred the new Laminaria hyperborea fronds both as habitat and food. There was a large variation in the phlorotannin content among the tissue samples of L. hyperborea. However, there were no overall statistically significant differences in tissue nitrogen or phlorotannin content between the new and the old L. hyperborea fronds.

Juveniles of 33 non-resident fish collected in three sheltered shallow coves (eastern Adriatic) fell into three groups: (a) occasional (10 species); (b) present in the study site only for short periods and at small sizes, in transit to a nearby Krka Estuary (11 species); and (c) species that spend most or all of their juvenile phase in sheltered coves (12 species). This note provides suggestive evidence that shallow water habitats inside sheltered coves could play an important role as nurseries for fish groups (b) and (c) during their early life stages.