Blooms of the dinoflagellate, Gyrodinium aureolum have been recorded on the coasts of Europe and are fully reviewed by Tangen (1977) and Boalch (1979). The significance of these blooms is considerable, and with the increase in the eutrophication of inshore waters they are now an important factor influencing the ecology of coastal waters (Boalch, 1984). Their numbers increase to concentrations in excess of five million cells per litre during warm, stable conditions resulting in the waters becoming a greenish-brown colour, ‘slimy’ and with a characteristic smell (Boalch, 1979; Jenkinson, 1986). At these concentrations there are reports that local fauna may be adversely affected and certain species will die.

During a period of five years in the mid-1970s, fish were collected at weekly intervals from the Severn Estuary and Bristol Channel. The resultant data on the abundance and lengths of these fish have provided valuable information on the times when the juveniles of several marine species are recruited into the estuary and on their pattern of growth during the first years of life (Claridge & Gardner, 1977; Titmus, Claridge & Potter, 1978; Claridge & Potter, 1983, 1984, 1985; Potter & Claridge, 1985). One of the marine species found in the Severn Estuary for which no seasonal data on density or body size have been presented is the sole, Solea solea (L.), whose relative abundance ranked it amongst the top ten species in two of the five years of our study (Claridge, Potter & Hardisty, 1986).

The gill-parasitic polyopisthocotylean monogenean, Hexabothrium appendiculatum and the skin-parasitic microbothriid monogenean, Leptocotyle minor share the same host, the common dogfish Scyliorhinus canicula. The larvae of these parasites are stimulated to hatch by host skin secretions and the behaviour patterns of these larvae have been found to be remarkably similar. The freshly hatched oncomiracidia of both parasites rarely remain swimming (in the presence of hatching stimulants) for more than 30 min; there is a strong tendency for the larvae to attach themselves temporarily or permanently by either the anterior or posterior ends to glass or Perspex surfaces. Other important features of the behaviour of these oncomiracidia are their erratic mode of swimming and their apparent lack of response to environmental stimuli such as light, shadows, mechanical disturbance or water currents. There is some evidence that the swimming oncomiracidia of both parasites may be negatively geotactic after hatching but this response is weak and of short duration. The erratic swimming pattern, the lack of response to environmental factors and the readiness to attach to available surfaces seem likely to be particularly favourable for the establishment of larvae on the surfaces of dogfishes foraging at the sea bottom and providing the hatching stimulus for drifting eggs.

The correlation between settlement rate, cypris age and anatomical maturation on the ultrastructural level was studied in female cyprids of Lernaeodiscus porcellanae, a rhizocephalan parasite of the porcelain crab Petrolisthes cabrilloi. There is no settlement on crabs until the cyprids are at least 2–3 days old, and maximum settlement activity is only reached 5 days after the moult from nauplius to cyprid (at 15 °C). Thereafter the settlement rate decreases again, possibly due to depletion of energy reserves in the non-feeding cyprids. Ultrastructural investigations show that the female cyprids cannot metamorphose into a kentrogon until 2–3 days after the moult from nauplius to cyprid, which explains the absence of settlement in young cyprids. Competence to metamorphose depends on changes in the cement glands, the epidermis and the antennules. The cypris moult cycle is arrested at an early stage and moult activity is only resumed after settlement. This ensures that the cyprids will not initiate metamorphosis while free-swimming.

Television cameras and video equipment are well established as tools in many areas of marine research and have been reviewed by Barnes (1963), Myrberg (1973), Harris (1980), and Holme (1984, 1985). The TV camera is usually mounted on a remote sledge (Machan & Fedra, 1975; Holme & Barrett, 1977) or submersible, often with arrays of lights, and lacks the manoeuvrability that is necessary for many types of detailed survey and behavioural recording. Commercial and industrial uses also demand high-resolution equipment that is often contained in bulky underwater cases capable of operating at great depths and well below that possible by the conventional SCUBA diver. It is not unusual for the equipment to be used in conjunction with external lighting units where natural light levels are too low for the use of ambient light, and is dependent on an external power supply normally situated in the surface support vessel or within a submersible (Sisman, 1982).

It has been shown that the early development of the monogenean Calicotyle kröyeri takes place in the rectal gland of its hosts (various species of Raja). Adult parasites were found in the rectal gland as well as in the cloaca. The invasion route followed to the rectal gland remains unknown, in spite of a search for post-larvae in scrapings from the cloacal lining, rectal lining and ventral skin near the cloacal opening and in blood vessels leading to and from the rectal gland. The growth of the hamuli is described.

Activity patterns of the first maxillae of Calanus helgolandicus and Temora longicornis, restrained in a flow-through system, were investigated using a micro-impedance electrode technique. Copepods were exposed to four dinoflagellate species of similar cell size with filtered sea water and the diatom Thalassiosira weissfloggi as controls. In short-term transition experiments the beat frequency of the maxilla changed rapidly with the introduction and removal of cells from the surrounding medium. Similarly the introduction of cell-free algal homogenate, filtered through a 0·2 µm membrane, produced elevated beat frequencies, evidence consistent with chemosensory food detection. During 24 h exposure experiments frequencies for Calanus on all dinoflagellate diets were lower than for the diatom, and in the case of Scrippsiella trochoidea did not differ significantly from the seawater controls. In Temora, frequencies when feeding on dinoflagellates, except Prorocentrum micans, were lower than on the diatom. With Scrippsiella trochoidea and Gonyaulax tamarensis beat frequencies were the same as those for the sea-water controls. Significant depression of frequency below that observed in filtered sea water was shown for both copepods when presented with the bloom-forming, Gyrodinium aureolum. Differences in beat frequency in response to dinoflagellate diets are mirrored by other aspects of feeding activity, gut contents, egg production and mortality.

The Talitridae are recognized as being difficult to identify (for example, Goodhart, 1941; Den Hartog, 1963) and it is thus not surprising that some species have been overlooked. Goodhart (1941) mentioned a new subspecies of Orchestia mediterranea Costa, 1853 which was not described, and the specimens are now lost (C. B. Goodhart, personal communication). During work on the biology of Orchestia in estuaries, two new taxa were discovered and tentatively given subspecific status (Wildish, 1969, 1970). Re-examination of the specimens in the British Museum (Natural History) and National Museum of Natural Sciences, Canada shows that both warrant specific status.

The cheliped stridulatory structures are described for Trizopagurus strigimanus, T. melitai, T. tenebrarum and T. strigatus.

Sound in T. strigimanus is produced during reciprocal flexion and extension of the carpo-propodite and mero-carpopodite joints of tightly apposed chelae. These underwater sounds occur as syllables, each of which is composed of damped pulses with a repetition rate of 36–303/s and a within-pulse frequency of 6–8 kHz. The maximum sound pressure level (peak to peak) 15 cm from the source was 24 dB re: 1 Pa.

The gastropod shells inhabited by T. strigimanus had a weak effect (5% pressure difference) on directional radiation of sound in the near field (5 cm) and no effect beyond 20 cm from the crabs.

Cavity resonance of the shells was predicted from a mathematical model, but only appeared important at a fundamental frequency of about 4 kHz, when tested in animals partially removed from their shells. A more significant effect was low-frequency vibration (100–300 Hz) imparted to the shells through direct contact by the hermit crab inhabitants.

Behavioural experiments suggested that the function of T. strigimanus stridulation is defensive, particularly against conspecific aggressors. This may reduce intraspecific competition for shells in Trizopagurus.

Within the hepatopancreas of the shrimp Penaeus semisulcatus the functional develop ment and subsequent decay of M-‘midget’ cells is described and linked with the moult cycle. During the feeding stages the frequency of M-cells increases and they each form a large dense vacuole which contains proteinaceous material. Precursors for this material are probably derived from the haemolymph as the cells have no direct contact with the lumen of the gland. During the non-feeding stages before and after ecdysis the contents of the vacuole are progressively removed, probably to the haemolymph. Finally the cells die before the animals recommence feeding.

Three genera of Acanthonotozomatidae have been recorded from the British Isles, Iphimedia, Panoploea and Odius. The latter genus is distinctive, but the former two differ from one another only in the relative development of the palp of maxilla 1, which is variable throughout the group. It is shorter than the outer plate in P. minuta and P. eblanae, a little shorter than the outer plate in I. vicina, equal in length to the outer plate in I. quasimodius and longer than the outer plate in I. obesa and I. serratipes. There appears, therefore, to be no good phylogenetic justification for separating the two genera, and following Ruffo & Schiecke (1979, 1982) the genus Panoploea is relegated to the synonymy of Iphimedia.

Cadmium, and its compounds, has been placed on the blacklists of most international pollution conventions by virtue of its toxicity, potential for bioaccumulation and persistence (Taylor, 1983).

The ability of many marine molluscs, and in particular gastropods, to accumulate Cd to a high degree in apparently unregulated fashion has led to their frequent use in monitoring programmes. Thus Cd levels in the winkle, Littorina littorea (L.) closely reflect gradients in environmental contamination (Bryan et al. 1983), demonstrating the excellent ‘indicator’ properties of this group.

The geographic distributions of most surface-dwelling species of planktonic Foraminifera are now well-known (Bé, 1959, 1960, 1977; Bé & Hamlin, 1967; Bé, Vilks & Lott, 1971; Bé & Tolderlund, 1971; Tolderlund & Bé, 1971; Bé & Hutson, 1977). These distributions, established from species abundance in plankton net collections, have been used to correlate abundance with physical and chemical variables (primarily temperature and salinity) in an effort to establish the factors which control the geographic range of these shelled protists. Significant correlations have been derived from these comparisons and the temperature and salinity ‘limits’ and ‘optima’ of a number of species have been reported (e.g. Bé & Tolderlund, 1971).

Stage-2 nauplii larvae were taken in near-surface inshore tow-nets on the Northumberland coast in January and February of 1986, confirming isolated reports of similar observations in 1979–80. These occurrences are much earlier than expected from the normally described progression of naupliar release in British waters. It is suggested that premature larval release may be occasioned by damage to, or predation on, parent colonies.

The effect of β-alanine on the concentration of taurine and other free amino acids (FAA) in different osmotic conditions in Mytilus galloprovincialis have been investigated. Significant variation of the concentration of FAA as a function of the salinity have been observed.

β-alanine incorporation decreases the level of cysteic acid and taurine as well as the level of other FAA.

Considerable work on deep-sea parasite faunas, including monogeneans, has been carried out in the north-west Atlantic (Suydam, 1971; Campbell, Haedrich & Munroe, 1980; Munroe, Campbell & Zwerner 1981; Zubchenko, 1981) and some in the Pacific (Gusev, 1957; Robinson, 1961), but work of this nature in the north-east Atlantic is limited mainly to species lists and descriptions (Gallien, 1937; Rees & Llewellyn, 1941; Brinkmann, 1952). The present paper presents observations on monogenean parasites of fishes from the Rockall Trough area of the north-east Atlantic.

Gross activity recordings from the recurrent facial nerve were made in unrestrained specimens of Gaidropsarus and Ciliata by means of implanted silver-wire electrodes. Responses to tactile stimuli could be evoked almost anywhere on the skin. Application of the contents of the urinary bladders of other rocklings, water in which other rocklings were kept, and (diluted) human saliva to the anterior dorsal fin evoked strong responses. Responses to more elementary chemical stimuli like amino acids, salts, aldehydes, and acids, were much weaker or absent. The results favour a special chemoreceptive function of the vibratile anterior dorsal fin.

Orbulina universa d'Orbigny is a spinose planktonic foraminifer which occurs throughout surface waters of the tropical, subtropical and transition zones of the world ocean (Bé & Tolderlund, 1971). This species is unique among planktonic Foraminifera in that its life cycle is composed of two growth stages. The juvenile stage is a trochospiral form which is enclosed within a terminal spherical chamber in the adult stage. O. universa is relatively omnivorous, and consumes a variety of prey that range in size and quality from phytoplankton to copepods (Bé et al. 1977; Anderson et al. 1979; Spindler et al. 1984). In addition, each individual harbors several thousand zooxanthellae which presumably are an additional source of nutrition for the foraminifer (Be et al. 1977; Hemleben & Spindler, 1983; Spero & Parker, 1985).

Two berycomorph fishes, Hoplostethus atlanticus and H. mediterraneus, were captured by bottom trawls on the continental slopes to the west of the British Isles. H. atlanticus was seldom abundant and was distributed at a depth of about 1250 m both in the Rockall Trough and the Porcupine Sea Bight. H. mediterraneus was only present in the Porcupine Sea Bight and was moderately abundant at depths of about 750 m. Few juveniles of either species were captured and there was no evidence to suggest that H. atlanticus spawned in the area. Seasonal changes in the gonosomatic index of H. mediterraneus indicate that spawning occurs in the autumn and that the environmental conditions at this northern limit of its distribution may be unsuitable for larval or juvenile survival. Juvenile H. mediterraneus were relatively abundant in bottom trawls off West Africa. The diets of both species were broadly similar in that they preyed primarily on benthopelagic organisms, especially mysids, decapods, fish and cephalopods.

During a short stay at the Marine Biological Association Laboratory Plymouth (mid-September 1982) preliminary investigations of the interstitial fauna of marine sand were carried out. The sampling sites with the recorded Mollusca have already been communicated (Salvini-Plawen, 1984).

As concerns mesopsammic Cnidaria, only a few findings have been made in British waters (Boaden, 1963, 1966; Harris, 1972). The present contribution reports not only new records for the Plymouth area and British waters in general, but also provides comparative knowledge of mesopsammic faunas.