The calanoid copepod Temora longiornis (Müller) has sub-cuticular secretory glands located on both the body and swimming legs. The glands are tri-cellular, consisting of a secretory cell (producing a proteinaceous secretion) opening through a cuticular pore, a collar cell surrounding the neck of the secretory cell, and a duct cell which lines the pore opening. The possible function of the secretion is discussed.

Mussels were fed four concentrations of seston (between 0·99 and 10·3 mg total seston I−1), comprising three levels of organic content (71·9, 63·6 and 40·8%), made up from natural silt and two species of cultured phytoplankton. Two of the seston concentrations were below, and two above, the threshold at which pseudofaeces were produced. Measurements of physiological traits (filtration rates, pseudofaeces production, selection efficiency, absorption efficiency, absorption rates and rates of oxygen consumption) were made after 2 days and, for two of the seston concentrations, also after 12 days. When fed at a high concentration of seston of low organic content, the mussels increased their filtration rate, rejected a higher proportion of filtered material as pseudofaeces, and increased the efficiency with which filtered matter of higher organic content was selected for ingestion; this resulted in a constancy of the relationship between ingestion rate and the concentration of particulate organic matter, regardless of differences in seston organic content. Between 2 and 12 d, the mussels increased absorption rates for organics, primarily by increasing absorption efficiency, both for total organics and for the carbohydrate component of the diet. We suggest that these responses to changes in the food environment comprise physiological adjustments which result in higher net rates of absorption than would be predicted from considerations only of the organic/inorganic ratio of the suspended particles and assumptions of a non-compensating feeding behaviour.

Rock pools are unique and complex habitats in intertidal areas. Quantitative studies of assemblages in pools are few. Abundances and distributions of species in pools on a rock platform near Sydney (Australia) were sampled for two years. Pools of four different depths (5, 15, 30 and 40 cm deep) and up to four strata within each pool (0–5, 5–15, 15–30 and 30–40 cm, from the top of the pool) were sampled, replicated at four sites. The abundances and distributions of most species of plants and animals in pools did not differ between strata nor at different depths in the pools. Abundances of only three species, the encrusting alga, Hildenbrandia prototypus Nardo, the trochid snail, Austrocochlea constricta (Lamarck) and the limpet, Cellana tramoserica (Sowerby) varied significantly between strata and depths. In contrast to other studies on rock pools, most species showed no significant temporal variations in mean abundances in the sites sampled. Significantly large, spatial and temporal, random fluctuations did, however, occur in abundances in individual pools. The consistency of abundances at larger spatial scales indicated that disturbance in these habitats may not be an important structuring process. The large variation between pools does, however, suggest that the history of each pool may have a more significant role in the character of its assemblage. Some implications of small-scale variability are discussed.

To examine density-dependent effects on growth in Cerastoderma edule (L.) (Bivalvia), growth rates of individual cockles established by chance at high and low densities on the same intertidal mudflat in two different years (1984 and 1989) were compared. Two-year-old cockles occurring at high densities (>2000 individuals m-2 in 1984) attained mean lengths from 16.1 to 18.8 mm on the lower shore at the end of their third growing season, while low-density cockles (<50 individuals m-2 in 1989) of the same age reached mean lengths in the range of26.5 to 30.3mm. In terms of individual weight the difference between cockles from the two periods was even more striking, as the flesh ash-free dry-weight of a cockle from 1984 constituted only 7% of that from a 1989 cockle. During both periods growth in cockles increased with the duration of tidal submersion, but the interannual growth differences exceeded by far the effect of differences in submersion time.

Since 1980 many papers dealing wholly or partly with the genus Fenestrulina have been published, mainly by Anglo-Saxon and South American authors: e.g. Gordon (1984, 1989), Hayward (1980), Hayward & Ryland (1990), Hayward & Taylor (1984), Moyano (1985). These studies have increased the number of species of the genus known around the world. However, few authors have worked on the genus Fenestrulina in European seas, probably because it was assumed that this taxon was well known in these regions.

Cephalothorax length and dry weight of copepodite stages and adults of the planktonic copepod Acartia clausi Giesbrecht in the Saronikos Gulf, Greece, were measured. Length-weight relationships and condition factor were also determined. The results were based on 17 zooplankton samples collected between November 1989 and June 1990, a period in which the abundance of A. clausi is significant. There was an inverse relationship between temperature and length, a pattern shown by many copepods. Temperature had the most significant effect on length, which was also affected by chlorophyll level. This strong temporal variation in length might possibly be considered as an adaptation of A. clausi to a continuously fluctuating environment. Length-weight regressions displayed high coefficients of determination (r2=0.98). Food, expressed as chlorophyll, affected the size and condition factor, and could act as a limiting factor on length and weight of A. clausi in the study area.

The stomachsof 23 striped dolphins (Stenella coeruleoalba Meyen, 1833, Cetacea), stranded along the Ligurian coast (western Mediterranean Sea), contained 32 species of cephalopods, crustaceans and fishes, totalling an estimated 2,723 prey specimens representing about 36 kg in weight. Cephalopods and bony fishes were equally important in the diet (50%). Todarodes sagittatus (34.5%) and Micromesistius poutassou (25.9%) were found to be the most important food species. Other species belonging to six cephalopod families, three crustacean families and nine bony fish families, contributed to the diet with variable numbers, weights, and occurrences, demonstrating the opportunistic character of striped dolphin feeding.

The relative abundance of the six copepodite stages (CI-CVI) of Calanus helgolandicus Claus (Copepoda: Calanoida) and Pseudocalanus elongatus Boeck (Copepoda: Calanoida) was recorded at a station in the English Channel throughout 1989. There was a pronounced seasonal variation in the abundance of the early stages. Increased recruitment from the nauplii corresponded in both species to rising primary production early in the year, producing small CI abundance peaks in March. The major period of naupliar development occurred after the April/May spring bloom. During seasonal peaks the CI and CII stages typically formed 40% of the copepodites of these species but were scarce at other times. The body carbon weight of Calanus and Pseudocalanus CIs decreased by 38% and 21% respectively from May to August, indicating an increase in food limitation for the nauplii. Summer was passed predominantly in the CIV and CV stage at low abundances.

The Pycnogonida are a group regularly recorded in deep-sea benthic samples, although normally in low numbers. Most analyses from such surveys record new species, and many of these remain known only from a few specimens, often only the types. However, the amount of deep sea-bed sampled is necessarily proportionately so small that it may be argued that any species taken are probably common, owing to their having been sampled at all. It is evident from the gaps in the (often world-wide) distribution of these known species and their limited occurrence that deeper water pycnogonid faunas are still at best poorly known (q.v. Child, 1982).

The species-specific abundance and biomass of marine planktonic ciliates were determined at monthly intervals at two stations in Southampton Water between June 1986 and June 1987. The two stations, an outer one at Calshot and an inner one at north-west Netley, were subject to differing marine and terrestrial influences. A total of 55 ciliate taxa were recorded during the sampling period; of these 34 taxa were identified to genus and 16 to species. The heterotrophic ciliate community at both stations was dominated by aloricate taxa which comprised >90% of the community abundance and biomass during some months. The loricate tintinnids were also common, especially at Calshot, during winter months. Oligotrichs dominated the aloricate community at both stations with haptorids prominent at north-west Netley. At Calshot, Strotnbidium sp. dominated the heterotrophic community abundance and biomass throughout the study period, while Askenasia sp., Strobilidium sp. and Tintinnopsis sp. were also common. Strombidium sp. also contributed most to heterotrophic community abundance at north-west Netley. Balanion sp. and Tintinnopsis sp. were also abundant. However, Cydotrichium sp. and Didiniunt sp. dominated community biomass at this station. Most taxa exhibited a seasonal cycle with low winter and high spring and summer abundances. Some taxa reached abundances of >2000 l1 However, maximum abundance of one species of Tintinnopsis was found during winter months. The autotrophic ciliate, Mesodinium rubrum, was also recorded at both stations achieving densities >105l1 at north-west Netley during ‘bloom’ conditions.

Observations were made on the reproduction and life history of five species of polychaetes collected from the continental slope off North Carolina, USA. Three species were studied at a 2000-m lower slope station off Cape Lookout (Aurospio dibranchiata, Microrbinia linea, and Pholoe anoculata) and the other two at a 600-m upper slope station off Cape Hatteras (Cossura longocirrata and Scalibregma inflatum). Aurospio dibranchiata, a surface feeding spionid, exhibited seasonally in egg diameter and size-frequency data, with the larger sizes occurring in late summer months. Pholoe anoculata, a small carnivorous scale worm, did not exhibit any evidence of seasonality in size-frequency data at the 2000-m station. Sexually mature specimens were absent from this population, but were present at shallower slope depths, indicating year-round recruitment into the lower slope from middle and upper slope populations.

The distribution of shore crabs, Carcinus maenas (L.), within the intertidal and shallow subtidal zones of a rocky shore in the Menai Strait, North Wales, was recorded regularly by diving throughout the tidal cycle. Samples were also obtained by searching the shore during low tide and by collecting crabs in baited pots. It was found that the smaller individuals (<35 mm carapace width) in the population tend to remain within the intertidal throughout the tidal cycle whilst others, mainly the red-coloured adults, appear to remain permanently below low-water mark. The remainder of the population, predominantly green males larger than 35 mm carapace width, migrate upshore with the flood tide and downshore again with the ebb. The behaviour of C. maenas on the shore appears to be affected, at least in part, by a tidally rhythmic pattern of responsiveness to directional light which is seen in freshly collected crabs in the laboratory.

The burial mechanism of Crangon crangon was examined in detail using high-speed video-recording equipment. Four stages of burial were identified which were associated with three modes of burial. As the mode of burial changed, a change in the angle of substratum penetration was also noted.

The effect of particle size on the burying ability of three discrete size classes of shrimp was examined using both artificially graded and naturally occurring sediments. Particle size was found to be a major influencing factor on the degree of burial achieved by C. crangon, but no significant effect of shrimp size on burying ability was found over the size range tested.

Between 1983 and 1989,66 stations in the north-eastern Irish Sea offshore from Sellafield, Cumbria, were sampled by Reineck box corer to assess the abundance and distribution of the benthic macro-infauna. A total of 40 taxa was identified, of which the predominant group was polychaetes. Cluster analysis of the abundance data showed a division into three station clusters. Simple discriminant analysis showed that the three clusters were correlated (P<0.01) with sand, silty sand and sandy silt sediments. However, the three station groups did not show any clear pattern of characterizing taxa with sediment classification. The bioturbating potential of each taxon is reviewed. A method of weighting abundance data by a factor representing an estimate of individual taxon bioturbating potential is also suggested. This technique is illustrated and discussed by using the weighted data in a further cluster analysis to identify probable areas of high inf aunal bioturbation off Sellafield.

A new species of the genus Clausophyes (Siphonophora, Calycophora) is described from four anterior nectophores collected in the Southern Ocean. This species is distinguished from others in the genus by the presence of a large, undivided mouth plate on the anterior nectophore. However, in order to establish the distinctiveness of two other species in this genus, namely C. moserae and C. galeata, which a recent author has suggested should have only sub-specific ranking, the anterior and posterior nectophores of those species are redescribed.

The dry weight and organic carbon content of eggs and components of Clyde spring herring eggs were measured at intervals during their development. Comparison with previously published data suggests that an increase has occurred in the weight of these eggs over the past thirty years. It is clear that only a small proportion of the material deposited in the form of herring spawn actually remains attached to the substratum when the larvae hatch and so is available for potential integration into the benthic food web. This was confirmed by the determination at intervals over two years of the organic carbon content of the gravel sediments on spawning grounds of the Clyde spring herring. Although the deposition of herring spawn resulted in an immediate marked increase in the carbon content of the spawning ground sediments, carbon levels quickly returned to pre-spawning levels and there was no evidence of any permanent or long lasting increase. This held true when the spawn died and decayed in situ and even when it was mixed into the sediment by wave action. The rapid decrease in carbon levels is attributed to the strong water movements which frequently occur over the spawning grounds.

Epipelic diatoms represented the dominant microphy tobenthos on the intertidal mudflats of the Severn Estuary, south-western Britain. Algal biomass (measured as chlorophyll a concentration) varied over a seasonal cycle and was strongly correlated with sediment shear strength and critical shear stress and therefore with position on the shore. High levels of diatom biomass were positively correlated with the concentration of colloidal carbohydrate within the surface sediments. The critical shear strength for incipient erosion was significantly correlated with position on the shore (moisture content) and with both chlorophyll a and colloidal carbohydrate, the latter being the best biochemical predictor for the incipient erosion threshold. The range of stress required to cause incipient erosion varied from 1.0 to 8.0 N m-2, with the sediment increasing in resistance landwards. Two-way analysis of variance using both moisture content and colloidal carbohydrate as variables explained the stability of the sediment better than individual pair-wise comparisons.

Spatial, seasonal and age-related differences in infection of the cockle, Cerastoderma edule, with the trematode Meiogymnophallus minutus were studied on the Exe Estuary, England. Prevalence of infection was 100% across all samples with mean abundances between approximately 300 and 1000 larvae per host (maximum=4930 larvae). Aggregration of M. minutus in cockles was extremely high (variancermean ratios >100) and increased linearly as abundance increased. Mean abundance was highest in cockles collected from muddy substrates where the average age of cockles was high. In summer, numbers of larvae fell to less than half of spring levels and then increased after infection by a new wave of cercariae in August. Cockles accumulated larvae for up to 2 y but not thereafter, and levels of aggregation fell in the oldest age class. A peaked pattern of mean abundance and aggregation with age may be a result of parasite-induced death of older hosts or may be due to the inability of cercariae to establish in older hosts.

Monthly samples of intertidal and near-shore Necora puber were collected over two years from a commercially unfished area around Plymouth (south-west England). A clear reproductive cycle, consistent between the two years, was observed, and relatively high numbers of ovigerous females were found from January to June. Zoeal release was estimated to occur from April to June. Ovigerous females had developing ovaries, indicating that sequential broods occur. During embryonic development, egg volume increased by 109%, and egg loss was significant, accounting for between 14 and 18.5% of initial brood number. Females suffering limb loss showed a further reduced brood size compared to females with a full limb complement. The sex ratio of immature crabs was 1:1, whereas the ratio for mature crabs was biased to males (1.46:1). Two sperm plugs were observed in 90% of early postmoult mature females, but 10% had only one or no plug intact, suggesting their failure to mate successfully. These results are reviewed in relation to the biogeography of N. puber and with reference to the developing fishery in the United Kingdom.

Notice is given of the presence of a previously un-reported oedicerotid amphipod species, Pontocra tes arcticus Sars, in the shallow sublittoral zone of the sandy beach at Kames Bay, Millport (Scotland). Distinguishing features from P. arenarius are the parallel-sided second coxal plates, strongly deflexed narrow rostrum and lack of sternal dark pigmentation patterns in both sexes. A key to the three species in the genus is provided.