An earlier time-series of the annual mean latitude of the north wall of the Gulf Stream is updated to give a series of values from 1966 to 1990. The trend is similar to those seen in plankton from the Continuous Plankton Recorder Survey around the British Isles. This connection may reflect the displacement of storm tracks across the North Atlantic.

Phagocytes of the starfishes Asterias rubens L., and Marthasterias ghcialis (L.) (Echinodermata: Asteroidea) phagocytose allogeneic and xenogeneic phagocytes in vivo, but form non-reactive aggregates or syncytia in vitro. The coelomocytes of the sea urchins Echinus esculentus (Mortensen) and Psammechimts miliaris (Gmelin), (Echinodermata: Echinoidea) also form aggregates or syncytia with allogeneic and xenogeneic cells in vitro. Mutual cy totoxicity could not be demonstrated either by enzyme-release or by decrease in numbers of viable cells in cultures of mixed origin as compared with autogeneic controls. The factors which may govern cell recognition and behaviour are discussed.

The evolution of a Phaeocystis bloom off Plymouth in spring 1990 is described. Data were obtained (1) during weekly visits to station El to measure physical parameters, nutrient concentrations, primary production and grazing pressure and (2) by regular tows of an Undulating Oceanographic Recorder around a circuit of five stations including El to detect stratification, monitor the geographical distribution of chlorophyll and determine vertical profiles at each station.

The data show that the Phaeocystis bloom emanated from near-shore, its spread towards the south-east correlating with the wind direction prevailing at the time. Due to bad weather, seasonal stratification had not been established at the time of the bloom so that a major diatom outburst had not occurred and nutrients remained high as the Phaeocystis moved offshore.

Zooplankton populations at El, averaged over 50 m, decreased whilst Phaeocystis was present, resulting in very low grazing pressure. Termination of the bloom was not, therefore, due to consumption by herbivores. It was, instead, caused by Phaeocystis colonies becoming nutrient-depleted and releasing single cells which were transported downwards. As a result of this, chlorophyll concentrations near the bottom remained high for some time after the Phaeocystis had disappeared from the surface water.

A scenario is proposed to explain the observations in terms of our current understanding of the ecophysiology of Phaeocystis.

The variation in species composition of continental slope fishes as determined by the catches of different trawls towed either on single or paired warps was analysed by Detrended Correspondence Analysis (DCA). The catches of two trawls, a semi-balloon trawl (OTSB) and a Granton trawl (GT) were very similar when towed on paired warps. Significant differences were found between the catches of the OTSB trawl towed on single and paired warps. The DCA effectively provided information on the important gradients, e.g. depth, trawl type, and indicated which species were most abundant in the different depth zones and trawl types. Detailed accounts of the abundance and biomass of different species by trawl type and depth zone are given and the observed pattern of distribution discussed.

Shell morphological features of the larvae and early postlarvae of species from two venerid (Mollusca: Lamellibranchia) subfamilies, Chioninae (Mercenaria mercenaria, M. campechiensis, M. campechiensis texana and Chionecancellata) and Pitarinae (Pitar morrhuanus), were examined using scanning electron microscopy. A single elongated fold on the anterior half of the left valve became more robust and a small fold in the centre of the right valve increased in length along the hinge line throughout the larval period. A MANOVA of shell length, shell height and provinculum length detected statistically significant (P) differences between the larval shells of Chioninae and Pitarinae, and within the Mercenaria.

Kidney and spleen tissues from flounder Platichthys flesus (L.) collected from Neal Point in the estuary of the river Tamar were examined by x-ray microanalysis for the presence of heavy metals within the melanomacrophage centres. Ultrastructurally these centres consisted of groups of pigment-containing macrophages in which melanin was the most prominent pigment, but lipofuscin and haemosiderin were also present. Some of the macrophages also contained irregular metal particles and minerals with associated metals. The metals identified within these inclusions were Ti, Cr, Fe, Co, Ni, Cu, Zn, Sr, Ag, Sn, Ba, La, Ce, Nd, W, Au, Pb, Th and U. The results are discussed in relation to the sediment chemistry of the River Tamar, and the possible routes of uptake by the fish.

Distributions of suspended matter, light attenuation and chlorophyll a were measured in the Shannon Estuary over the period 1988–1990. Light attenuation was found to be highly correlated with levels of suspended matter, and the availability of underwater irradiance was found to be the dominant influence on phytoplankton biomass and chlorophyll levels over most of the estuary. Though levels of suspended matter, and hence light attenuation, were highest in the upper estuary, depths of mixing were relatively shallow resulting in less light limitation of phytoplankton growth than elsewhere. Turbidity maxima in the upper estuary were associated with chlorophyll maxima, the magnitude of which appeared to be related to river discharge.

Specimens of a hydroid species previously unrecorded in Britain have been found during the course of a long-term study of the coelenterate fauna of an intertidal mussel bed in Morecambe Bay, Lancashire. Specimens were sent for examination to Professor J. Bouillon who indentified them as Rhizogeton nudum Broch.

The location and nature of the mussel bed, and the survey technique, have been described elsewhere (Jones & Miller, 1966; Jones & Clare, 1977; Jones, 1987). Rhizogeton nudum was observed in April and May 1987–91 and March 1989, on boulders where it was invariably associated with Clava multicomis (Forskal) and, more commonly, on mussel shells attached to these boulders. The few colonies recorded on boulders may have spread by stolon growth from attached shells.

Recoveries of tetracycline-labelled specimens of the sea urchin Echinus esculentus (Echinodermata: Echinoidea) from a wild population marked two years previously indicate very low skeletal growth rates in large adults. The post-tag growth in the test of a smaller specimen showed two clear growth zones in the middle layer of the plates, this conforming to the expectation of a single growth band each year. Merging of the spinochrome pigment bands present in the outer layer near the plate edge in older urchins will probably result in underestimation of age based on counts of these bands.

The large literature on growth banding in the European sea urchin Echinus esculentus L. and other echinoids is reviewed by Pearse & Pearse (1975), Smith (1980) and Gage (1991). Moore (1935) utilised spinochrome pigment banding in the genital (apical) plates of E. esculentus from the Isle of Man (Irish Sea) and Firth of Clyde (western Scotland) in one of the first studies utilising growth bands to interpret the age structure and growth rates of sea urchins. A single band was assumed to be formed each year. Counts of spinochrome bands have been used to obtain nearly all subsequently published age data for this species (Sime, 1982; Nichols et al., 1985; Sime & Cranmer, 1985; Comely & Ansell, 1988).

The present study was aimed at helping to resolve differing interpretations of age and growth rates in Echinus esculentus provided by these studies. This was undertaken by time marking the skeletal plates of a large sample of a wild population accessible by scuba diving on a submerged rock reef at 10–15 m depth off the islet of Eilean Mor near the Dunstaffnage Laboratory.

It has been argued by Johannesson & Johannesson (1990b) that the pattern of common genetic variation in Littorina saxatilis (Olivi) and Littorina neglecta Bean indicates gene flow in sympatric populations of these ‘species’. They suggest that L. neglecta is not a good species. We report that a gene diversity analysis of polymorphism in Aat-1 suggests that L. saxatilis and Littorina arcana Hannaford Ellis also show common features in allele frequency distribution. This casts doubt on the argument of Johannesson & Johannesson (1990b) from enzyme polymorphism data on Aat-1 that L. neglecta may simply be an ecotype of L. saxatilis. It seems likely that the similarities are due to operation of the same selection factors on all these species.

Respiration rates normalized to chlorophyll a of laboratory cultures of Brachiomonas sp., Gyrodinium aureolum, Synechococcus sp. (clone WH 7803), Pycnococcus provasolii (clone W48–23) and Phaeocystis sp. showed a positive relationship with growth photon flux density (Ig). It is argued that this constitutes an energy conserving strategy of adaptation to conditions of low irradiance. The ratio of respiration to light-saturated rate of photosynthesis (R/Pmax) also showed a decrease with decreasing I. Algal cell size, within the investigated range (0·2 to 1380 pg C cell-1), showed little influence on biomass-specific respiration rates.

Spherical, opaque bodies (5–10 µm diameter) were frequently observed adhering to cells of the marine ciliate Mesodinium rubrum, particularly towards the end of red-water blooms in Southampton Water. Transmission electron microscope sections revealed these structures to be of biogenic origin, and packed with an amorphous, lipid-like material. No diagnostic features were observed to confirm their identity.

The phototrophic ciliate Mesodinium rubrum (Lohmann) forms recurrent red-tides each summer and autumn in the Southampton Water estuary, UK (Williams, 1980; Soulsby et al., 1984). During a study of the impact of these blooms on the estuary, live cells were routinely observed microscopically. Frequently, but predominantly later in the bloom, numerous individuals posessed spherical, colourless, but opaque bodies, apparently attached or adherent to the outer cell membrane. Cells observed prior to the bloom, or at other times of the year, were never observed o possess such structures.

Cells bearing these bodies were photographed live, or after preservation in Lugol's iodine, using the phase contrast optics of an Olympus BH2 photomicroscope.

The pericardial gland of the deep-sea hydrothermal mussel Bathymodiolus thermophilus (Mollusca: Bivalvia: Mytilidae) differs from other mytilids by (1) a narrow lumen and (2) conspicuous polyhedral inclusion bodies in large cytoplasmic vacuoles of the epithelial cells. These inclusions do not contain metals as revealed by microanalysis but are possibly made of proteins. The cells of this gland exhibit a fenestrated basal border which indicates a site of haemolymph ultrafiltration. The kidney is histologically comparable to that of the coastal mussel Mytilus edulis.

The capture of the short-beaked garfish,Belone svetovidovi Collette & Parin 1970, off the Cornish coast is of particular interest in that it represents an easterly extension to the known range of this species in the eastern North Atlantic, and the first record in British waters.

In August 1990 seven garfish were angled, on mackerel bait, in Mount's Bay, Cornwall. The captor, Mr A.C. Cass, believing the garfish to be different from the common garfish,Belone belone (L.), sent the largest one to the laboratory of the Marine Biological Association for identification. The specimen was provisionally identified as the short-beaked garfish B. svetovidovi and later verified by one of us (A.W.). The other six specimens were not available for examination.

Garfish, sometimes called needlefishes, have elongated bodies. Both upper and lower jaws are long and beak-like, with sharp teeth. They are epipelagic, feeding near the surface and are often observed leaping and skittering over the surface of the water. Only two species are recorded in the genus Belone in the north-eastern Atlantic.Belone belone (including subspecies) is commonly found off the European Atlantic coast as far north as Trondheim, Norway. It is also found in the North Sea, the southern Baltic seas, the Mediterranean and Black Sea where it is commercially exploited (Collette & Parin, 1986).Belone svetovidovi has only recently been distinguished from B. belone, and consequently its abundance and distribution are less well known. It was first identified in northern European waters by Dorman (1984,1987) from southern Ireland.

A new species of Fenestrulina Jullien, 1888, F. asturiasensis sp. nov., is described from the northern coast of the Iberian Peninsula. The main diagnostic features of this species are: four to five oral spines, a completely porous frontal wall and non-stellate frontal pores. These features have allowed the author to differentiate it from F. malusii (Audouin), another species of the genus Fenestrulina Jullien recorded in the same region.

The ciliate list for Plymouth waters has been extended by 14 species using modern taxonomic techniques. Ciliates were abundant in the plankton where they formed a significant food resource. Their community biomass and production was estimated to average 12 µ C 1 and 9 µ C 1 respectively during the summer. The ciliate community was dominated by a diverse assemblage of aloricate choreotrichs, suggesting a complex trophic role for this protozoan group.

Ciliate protozoans are ubiquitous and often abundant in marine waters where they are frequently considered to play an important ecological role in trophic flux and nutrient cycling within the plankton (Fenchel, 1987). In spite of this, however, their ecological role in British coastal waters is poorly understood. In Plymouth waters, for instance, there has been only one previous study of marine pelagic Protozoa (Lackey & Lackey, 1963), despite the presence of a marine laboratory in the region for over 100 years. As the study by Lackey & Lackey (1963) focused solely upon the taxonomy of local protists, the ecological role of protozoans in Plymouth waters is unknown. To redress this anomaly the present pilot study was undertaken in Plymouth waters with the following objectives: to identify the dominant ciliates from this region using techniques unavailable to Lackey & Lackey (1963), to quantify ciliate abundance and cell sizes, and to estimate their biomass and production.

Triplicate water samples were collected, using a 3-litre water bottle, from surface waters at each of four stations along a 20-km transect between Plymouth Sound (50°21'N 04°09'W) and the Eddystone Rock (50°ll'N 04°16'W) during June, July and August 1988.