The fine-scale structure of a bloom of the coccolithophorid Emiliania huxleyi has been mapped for the first time with an airborne thematic mapper (ATM) scanner (visible bands at 420–450 nm, 450–520 nm, 520–600 nm, 605–625 nm and 630–690 nm). The airborne results are in close agreement with simultaneous satellite observations from the visible band (580–680 nm) of the advanced very high resolution radiometer (AVHRR

A testate amoeba with organic test, isolated from sediments in the Firth of Clyde, Scotland, has been assigned to a new genus as Ovulina parva (Protista: Filosea) based on its unique light microscopic and fine structural morphology. The hyaline to amber test is ovate (~15×ll µm) with a terminal aperture that is either unadorned or with a shallow collar. Hyaline, long-tapering, pointed, sometimes branched, pseudopodia emerge directly from the aperture or from the periphery of a thin web of hyaline cytoplasm. The nucleus (~5 μm) with a central nucleolus (~2 μm) is located at the posterior of the cytoplasm. The fine structure of the test, examined by scanning and transmission electron microscopy, shows it is entirely organic with an irregular to granular surface. Scattered elongate pits (~1 μm long) without perforations are distributed irregularly on the surface. Ectoplasm is distributed within a fine fibrillar envelope lining the test. The endoplasm is ovoid and contains anteriorly located vacuoles enclosing densely-staining bodies with chromatin-like filaments which appear to be bacterial prey in late stages of digestion. This is further corroborated by light microscopic observations that bacteria are cleared from the surface of the culture dish within the circumference of the pseudopodia. The mitochondria (0.5–1.0 μm) have tubular cristae and some are located in the vicinity of peroxisomes (~0.5 μm) surrounded by a single membrane and with a finely granular matrix. Minimum doubling time in our cultures was 28.4 h, and the testate amoeba exhibits remarkable salinity tolerance growing in media ranging from 0 to 35% salinity.

A new species of sponge, belonging to the genus Delectona, has been observed in the scleraxis of Corallium rubrum from three Mediterranean banks (Alboran, Elba Island and Bosa Marina). The species, described here as Delecfons ciconiae, shows a spicular complement composed of spiny rhabds, very irregular in shape and size, whose derivation from amphiasters has been suggested; toxiform centrotylote oxeas; slender, irregular amphiasters and subcircular or ovoid rough discs. The taxonomic position of this species, within the Clionidae, has been discussed.

A new Myxillidae species from the Strait of Gibraltar, Myxilla tarifensis, is described. It is easily distinguished by a characteristic irregular isodictyal reticulation of acanthostyles which are smooth or slightly spined at the heads, as well as by strongyles as ectosomical megascleres, sometimes with very small and short spines at the ends. Moreover, the recent synonymization of the genera Dendoryx, Burtonanchora and Pseudomyxilla is accepted. A brief diagnosis is given of the Myxilla species found in the Strait of Gibraltar.

Two types of electron-dense inclusions are described using transmission electron microscopy from the marine nematode Tripyloides marinus (Nematoda; BÜtshli, 1874) isolated from a metal-enriched site and a site of low metal contamination. These were classified as granular, intracellular inclusions in the intestinal syncytium, and fluid-filled vesicles along the cuticular margin of the epidermis. Energy-dispersive x-ray analysis (EDX) showed that the intestinal granules were largely comprised of P and S, with variable levels of Ca, Cu, Zn, Fe and Br, and that the epidermal vesicles contained high levels of Br and S with variable levels of Ca, Cu, Zn, Fe and P. It is suggested that intestinal granule formation may be involved in the detoxification of heavy metal sulphides and might result in a heightened ability of the species to colonize metal-enriched sediments. The function of the cuticular vesicles is unclear, but might be linked to a predatory or microbial defence mechanism (Woodin et al., 1987), or as part of a metal detoxification system.

This paper summarizes the available information on the distribution and biology of Maxmuelleria lankesteri. This large echiuran was described almost a century ago but its local abundance and potential importance as a bioturbator were recognized only recently. The species is widespread around the British and Irish coasts, most commonly in fine muds. A deep-burrowing, nocturnal deposit feeder, M. lankesteri is unlikely to be seen by divers, but its presence can be deduced from the form of ejecta mounds and proboscis tracks. The worms are very difficult to capture intact. Body size in a sample from Loch Sween, Argyll, was approximately normally distributed. Very small individuals are rarely found. Developing oocytes were found in the coelom over the spring and summer. Mature eggs accumulate in the gonoducts, with maximum loads found from October to December, possibly indicating a single annual spawning during the winter. Despite intensive examination of a large number of adult females, no dwarf males were found, leaving open the question of their existence. The large, yolky eggs indicate lecithotrophy or direct development. Larval stages have not been recognized. The apparent scarcity of developmental stages and of very small adults suggests that recruitment may be sparse and infrequent.

Ninety-six species (97, 677 individuals) were collected over the course of 6 h in five suprabenthic sledge hauls from a very dense Ampelisca fine sand community from the Bay of Morlaix (western English Channel). All the species migrated into the water column at night (98% of the specimens collected in the suprabenthos were found in the night hauls). The 23 most abundant species collected were classified into five groups based on their height within the water column, but two groups predominated: the upper suprabenthic species, abundant at 0–80–145 m above the sea-bed; and the lower suprabenthic species which were abundant only near the sea bottom (-0–1–0–75 m high). Three different patterns of nocturnal vertical migration were distinguished based on the timing of maximum swimming activity: at dusk; at the beginning of the night; or later in the night. Sexually dimorphic patterns of free-swimming behaviour was observed in Ampelisca and some other species of Amphipoda (Bathyporeia teniupes, Metaphoxusfultoni), and Cumacea (Bodotria pulchella, Pseudocuma longicornis), with many more males than females migrating into the water column at night. Finally, the density of suprabenthic crustaceans in nocturnal hauls was amongst the highest reported from infralittoral or circalittoral suprabenthic studies on other parts of the Atlantic Ocean sampled during spring.

Results of a comparative study on the distribution, growth and reproductive bionomics of two species of sand-dwelling oedicerotid amphipod, Pontocrates arenarius and P. Altamarinus are presented. Pontocrates arenarius is a littoral species with highest population densities between mean tide level (MTL) and low water springs (LWS) while P. altamarinus lives in the immediate sublittoral between LWS and -2 m Chart Datum. Both species are iteroparous, have female biased sex ratios, year-round breeding and life cycles largely based on two generations per year. The percentage of ovigerous females in the total population indicates breeding activity, and temporal changes in this percentage (arcsin transformed) have been tested for correlations against seasonal variation in five environmental factors (mean maximum weekly air temperature, mean minimum weekly air temperature, mean weekly sea temperature, day length, and mean weekly windspeed). Based on these analyses, differences in the timing of peak reproductive activity between these two species are interpreted as indicating the operation of different mortality agents, i.e. abiotic factors in the littoral P. arenarius and biotic effects (e.g. predation by fish) in P. altamarinus from the sublittoral.

Iorania concordia gen. nov., sp. nov. (Crustacea: Decapoda) belonging to the family Alvinocarididae is described from the Mid Atlantic Ridge, TAG location (26°09'N 44°50'W). The taxonomic position in the family and distinguishing characters (rostrum, armature of telson, form of first maxilliped) of the new genus are presented, and a possible evolutionary feeding hierarchy within the family is suggested. A key is given to the genera of the Alvinocarididae.

From May 1993 until January 1994, 788 male and 1604 female crawfish, Palinurus elephas in total, were examined from the South Wales and Cornish fisheries. Mean carapace length (CL) of Cornish crawfish was 125.6 mm for males, 132.4 mm for females and 135.0 mm for berried females, while mean CL for Welsh crawfish was 155.8 mm for males, 138.7 mm for females and 138.6 mm for berried females. The overall size distribution of male Welsh crawfish differed significantly from that observed in the Cornish population. An analysis of variance gave significant (P<0.05) differences for the factors; Site, Sex and the Sex/Site and Month/Sex interactions. Male crawfish reached greater overall size than female crawfish, but for specimens of equal CL, total lengths (TL) of females were longer than those of males. Males were heavier than females of equal CL or TL.

South Georgia, an extremely isolated island within the Antarctic Convergence, was covered by an extensive icecap until ~10,000 years ago. In consequence the depauperate intertidal fauna is of recent origin and consists almost entirely of brooders or direct developers which probably arrived as a result of rafting. Environmental conditions between the tidemarks are comparable with northern Norway and Greenland, so the absence of mussels and barnacles is due to isolation from the nearest feasible sources of colonization (the Falkland Islands and Magellan), and not to a hostile environment. Intertidal animals (eight species studied) have median upper lethal temperatures that are positively and linearly related to maximum height of distribution on the shore. Thermal niche width (median upper lethal temperature minus median lower lethal temperature) is also positively correlated with maximum height of distribution on the shore with species below mid-tide level having narrow niches in contrast to species above mid-tide level that have wide niches. There is no relationship between freezing resistance and position on the shore. Salinity and desiccation tolerances were also greater in animal species from the upper shore than in those from the lower shore. In the case of those species also studied elsewhere (Lasaea rubra (Mollusca: Bivalvia); Nacella condnna (Mollusca: Gastropoda) and Tigriopus sp. (Crustacea: Copepoda)), evidence is presented to show that no special adaptation is exhibited by South Georgian animals, and that upper zonation limits are controlled primarily by physical tolerance. This is particularly marked in the case of N. condnna which has similar thermal tolerances on the Antarctic Peninsula, on Signy Island and at South Georgia; in consequence it can only inhabit the extreme lower shore at South Georgia, yet penetrates to mid-tide level at Signy Island.

Breeding and population statistics were assessed from February 1993 to September 1995 in a mixed population of the mudsnails Hydrobia neglecta and H. ulvae in the intertidal zone of a macrotidal bay on the Atlantic coast of Brittany, France. The biology of H. neglecta in the mixed population was identical to that found earlier for the same species when living allopatrically elsewhere in the bay, and was also that generally characterizing directly-developing species of Hydrobia that occur in coastal lagoons. The population of the larviparous H. ulvae also showed various features otherwise typifying lagoonal populations of this species: very high juvenile mortality, repeated failure of whole cohorts to recruit, and an age structure dominated by large and relatively old individuals. The number of eggs per capsule was normal for an intertidal H. ulvae population but the number of capsules laid was remarkably low. Why both species should behave in this intertidal marine habitat as if it were lagoonal is unknown. The failure of the cohorts of H. ulvae deriving from spring eggs in the bay may help explain why the majority of lagoonal populations of this species are dominated by old mudsnails and show negligible recruitment. There was no evidence of competitive displacement of H. neglecta by H. ulvae in spite of received wisdom that H. ulvae is the competitive dominant under fully marine conditions; mortality of H. ulvae was more than three times that experienced by H. neglecta regardless of age of the snails.

Five, possibly six, north European species are confirmed in the prosobranch genera Rissoa and Pusillina: R. parva (Da Costa); R. lilacina Récluz; R. membranacea (Adams) (types A & B); P. inconspicua (Alder) and P. sarsi (Lovén).

The five species differ ecologically in salinity tolerances, with R. membranacea and P. sarsi being the most tolerant and regularly occurring at salinities of 7–10%0, while R. parva, R. lilacina, and P. inconspicua tolerate salinities down to 20%0 (for shorter periods 15%0). There are also differences in the ability to survive occasional, short exposures to highly reduced salinity with 50% survival for R. membranacea after 80 h; R. lilacina, 30 h; P. sarsi, 25–30 h; and for P. inconspicua after 15 h exposure to freshwater at 8°C. At higher temperatures the survival is lower. There is a difference in the requirements on water circulation, with R. parva and R. lilacina preferring more current-swept and exposed environments.

Rissoa membranacea occurs in two types, possibly species, with planktotrophic and lecithotrophic larval development respectively. In Scandinavia, populations with lecithotrophic development have a restricted occurrence between Sjaelland and Jylland in Denmark, but may be more common in the UK and France. Such specimens are always accompanied by the planktotrophic form, and it can not be excluded that the two forms are conspecific and this is a case of poecilogony. There is also a possibility that P. sarsi actually constitutes a series of populations of P. inconspicua adapted to local, more brackish conditions by larger egg size and veligers, but the two are regarded as distinct species.

Mytilus edulis (Mollusca: Bivalvia) collected as spat from the wild in 1990 and held in the laboratory for 18 months were divided into four groups: fed (control); starved; fed with 100 ppb added copper; and starved with 100 ppb added copper. Following >60% mortalities in the starved and copper stressed groups (but negligible mortalities in the control) surviving mussels from all four groups were genotyped at seven allozyme loci (Gpi, Lap, Pgtn, Idh, Odh, Gsr and Est). Allele frequencies did not vary significantly between any of the four groups at any loci, except Gsr where fed and starved groups differed. Mortalities were not genotype dependent at the Pgm locus but, in contrast, genotype frequencies at most other loci varied significantly between groups. At the Gpi, Lap, Gsr and Odh loci there were significant changes in proportions of heterozygotes following copper induced mortalities such that, in general, heterozygotes survived longer and homozygotes succumbed sooner. No similar pattern was evident in relation to mortalities caused by starvation; at only one locus (Idh) was there evidence of a significant effect but this was not apparently independent of the effect of copper.

The mussel Mytilus edulis (Mollusca: Bivalvia) feeds on suspended matter filtered from the sea-water by cilia on the gill surfaces. The bivalve will clear the inhalant water of all particles >2–3 (xm including both sediment and organic matter. Marine sediments act as sinks for a variety of pollutants which may be concentrated up to 1000 fold above water levels. In a series of experiments, the uptake of zinc by M. edulis from filtered sea-water was compared with that from sea-water containing particulate matter acting as model sediments. The materials were two different ion-exchange resins, inorganic granules and hydroxyapatite particles. The accumulation of zinc from the particles was related to the amount of zinc adsorbed by the particles and to their surface properties.

The size of fish and squid prey of Loligo forbesi was investigated using otoliths, beaks and statoliths collected from stomach contents analysis of samples obtained from Scottish and Irish waters between 1990 and 1993. Loligo forbesi was found to consume a large range of prey sizes, but prey size was always less than the predator size. Season was shown to significantly influence the predator size-prey size relationship for sprat and sandeel prey, but this itself could be influenced by seasonal changes in the size of prey. Fish prey size increased with increased predator size up to a mantle length (ML) of 200 mm. Loligo forbesi of mantle length >200 mm consumed a range of prey sizes, with no clear increase in the size of prey. For most prey taxa the relationship between prey size and squid size was similar, the exceptions being dragonets and silvery pout. Cannibalism by L. forbesi was mostly limited to larger L. forbesi (>150 mm ML) feeding on smaller (20–50 mm ML) conspecifics.

Statolith microstructure was studied in 162 specimens of Illex coindetii (mantle length ranging from 48 to 300 mm) captured on the shelves of Sierra Leone and Western Sahara between May and November 1987. Growth increments were revealed in all statoliths studied, but they were not well-resolved as in other congeneric species Illex illecebrosus and Illex argentinus. Age and growth rates were estimated assuming that growth increments within statoliths were produced. In both regions, differences in growth rates between sexes (females become larger than males) occurred first in length and then in weight. Geographical differences in sex-specific growth (Western Sahara squid grow faster and attain larger sizes than Sierra Leone squid) was apparent after 150 d in females and 120 d in males. Illex coindetii in Sierra Leone started maturing at smaller sizes but at approximately the same age as the Western Sahara squid. Small sized early maturing groups of I. coindetii with a life span of ~0.5 y occurred in both regions. However, large sized late maturing squid with a life span of ~1 y were encountered only in the Western Sahara. In waters of the west African shelf, I. coindetii spawn throughout the year.

A hydraulic dredge survey was conducted during January – June 1994 in north-west, north and east Iceland, to provide a first assessment of ocean quahog, Arctica islandica (Mollusca: Pelecypoda) resources in these areas. Ocean quahog was found in significant concentrations and high density. The combined high-density areas were 91.7 km2 with a minimum biomass (live weight) of 304.80 tonnes. Information on population structure and meat yield were also provided. The population in the areas was characterized by unimodal size distributions comprised of mostly larger-sized individuals. Most quahogs were between 70 and 90 mm with no individuals <17 mm which might be due to the selectivity of the dredge or because of poor recruitment in the population. Little difference was observed when comparing the mean shell length for the quahogs from the three areas. The mean shell length in the north-west area was 75.4 mm and 74.8 mm in the north and east areas. The shell length frequency distribution for the north-west area was different in shape from the two others which were not significantly different from each other. Mean quahog meat yields in the areas were from 30.1 to 33%. The meat yield was highest in the 50.55 mm size class in all areas.