During July 1984, large numbers of the sandy beach bivalve Donax vittatus (da Costa) were found either stranded in the intertidal, or washing to and fro in the surf on beaches at Dornoch, on the east coast of Scotland. The affected bivalves all carried large growths of several species of algae. The normal burrowing and recovery responses of the bivalves were unable to overcome the increased drag resulting from these epizoic algal colonies so that wave action caused dislodgement from the sand and eventually, stranding and death from dehydration. The resulting mortality affected mainly older individuals in the population; younger individuals had very small or no attached algae and were not dislodged.

The algal growths were complex and showed three stages in their development: primary settlements formed generally short tufts or mats attached to the posterior tip of die shell; secondary ‘dominant’ species were also attached to die shell but formed larger growths; tertiary species were attached as epiphytes to the primary and secondary growths. At least eight species of algae were involved. Juvenile mussels (Mytilus edulis L.) were also present in many cases attached to the weed, adding further to die drag.

During 1985, at Dornoch, secondary and tertiary algal species developed progressively from overwintering primary settlements, but the size of die algal colonies which developed was generally smaller dian in 1984 and diere was apparently little dislodgement and mortality.

Donax vittatus populations on other beaches in die Moray Firdi, and on most other Scottish beaches examined, had fewer individuals with attached algae, and diose affected carried only relatively small colonies which did not prevent normal burrowing. Complex algal colonies, showing even greater species diversity than those of Dornoch were, however, found on D. vittatus on beaches in South Harris, Outer Hebrides, during September 1984.

A portable light-trap was designed and constructed to assist in Museum taxonomic studies on Crustacea. The trap was constructed throughout of transparent Perspex. The light-source was a chemoluminescent ampoule marketed under the name Cyalume® Lightstick. The present trap offers several advantages. It is inexpensive to construct, sturdy, readily portable, easy to operate, and safe to use. Field trials in Lough Hyne (Ine), Co. Cork, south west Ireland, have proved the apparatus to be most successful in attracting a wide variety of crustaceans.

The spatial and vertical distributions of alkaline phosphatase activity (APA) in the western English Channel in July 1987 were determined using 2 μM 3-O-methylfluorescein phosphate as substrate. The response of APA to increases in substrate concentration followed Michaelis-Menten kinetics but differences in Ks values between stations suggested a species dependency of the half-saturation constant. Phosphate inhibition of APA was, however, similar at 3 locations. The chlorophyll specific APA (SAPA) in surface waters ranged from 0.004 to 0.57 nMPO43- μg chla-1 min-1 and was inversely exponentially related to the chlorophyll a concentration reflecting the fact that phytoplankton populations are largest where inorganic nutrient availability is greatest and synthesis of the enzyme is not derepressed. SAPA values were found to be low in the bloom of Gyrodinium aureolum in the Ushant front and in the sub-surface chlorophyll maximum in the stratified region. Vertical distributions of SAPA are discussed in terms of the hydrographic characteristics of the water column and an attempt has been made to distinguish between APA associated with phytoplankton and with bacteria.

Two hundred Chlamys varia (L.) from Roskeeda Bay (W. Ireland) and Lough Hyne (S. Ireland) were collected and labelled in December 1979. One hundred individuals from the L. Hyne sample were then transferred to Roskeeda; similarly, 100 Roskeeda scallops were transferred to L. Hyne. At each site 100 indigenous scallops were held as controls.

After a period of approximately 1 year, survivors at each site were scored at 13 enzyme/protein loci using starch gel electrophoresis. Significant genetic differences were observed at the Pgm and Lap loci between native L. Hyne and native Roskeeda scallops. These differences persisted between surviving Roskeeda scallops (92% of the original sample) transferred to L. Hyne. However, after one year L. Hyne scallops transferred to Roskeeda (61% of original sample) did not differ significantly from indigenous Roskeeda scallops. Possible reasons for the observed selective mortality at this site are discussed.

Ten species of marine strombidiid ciliates were identified after protargol staining plankton samples. The taxonomic redescriptions include a diagnosis for Tontonia gracillima Faure-Fremiet, 1924, Strombidium wulffi (Wulff, 1919) Kahl, 1932, Strombidium acutum Leegaard, 1915, Strombidium constrictum (Meunier, 1910) Wulff, 1919, Strombidium compressum (Leegaard, 1915) Kahl, 1932, and Strombidium sulcatum Claparede & Lachmann, 1858. Four new species, Strombidium dalum n.sp., Strombidium epidemum n.sp., Strombidium rhynchum n.sp., and Strombidium tressum n.sp., are defined based primarily on the characteristics of the anterior oral polykinetids, numbers of oral polykinetids, and presence of anterior protuberance.

The sea stickleback, Spinachia spinachia, lives in shallow coastal and estuarine waters where the male builds a nest and undergoes a protracted period of parental care. The accumulation of silt in the nest has been suggested as one of the environmental factors that regulate nest-directed activities during the parental phase. Experiments have quantified the behaviour of the male fish before and after the application of silt to the nest and shown that some behaviours are affected. The fanning activity, attendance at the nest and other nest-directed activities were examined and it was found that nest inspection and nest pushing increased significantly following the application of silt. Fanning activity, a major part of the parental behaviour of the sticklebacks, was unaffected by the experimental treatment and seems to be unresponsive to environmental changes. The results are discussed in relation to the functional significance of parental behaviour, and compared with a closely related species.

An event/time recorder is described which is contained in a sealed waterproof case, with no external electrical connections and which uses novel methods for communicating control and data signals, and for charging the internal battery. The instrument is designed to be used underwater for recording behavioural and faunistic census information. On return to the laboratory the data can be retrieved, stored and processed using a microcomputer. The instrument is uncomplicated to use, completely waterproof, of a size that is easily carried and robust enough to withstand hard usage.

Samples collected from power station intake screens between 1972 and 1977 have been used to study aspects of the biology of the whiting in the Severn Estuary and Bristol Channel. 0+ whiting generally started appearing in the inner estuary in July, at which time their standard length was at least 38 mm. Their numbers peaked in October and subsequently declined particularly rapidly during the wet winter of 1976/7 when salinities were frequently below 10‰. The size of 0+ whiting in the late autumn and early winter was generally less in the shallows of the Inner Severn Estuary than in neighbouring deeper waters and in the Inner Bristol Channel. Growth rates of 0 + whiting fell within the range of those recorded for the North Sea, but below those generally found in inshore waters and sea lochs on the west coast of Scotland. Following their immigration into inshore waters in the Bristol Channel and Inner Severn Estuary, young whiting became infected with the copepod parasites Lernaeocera branchialis and Clavella adunca and the metacercariae of the heterophyid digenean Cryptocotyle lingua. Prevalence of infection was less in 0+ than older fish and infection by L. branchialis caused a significant decline in condition. As whiting became larger, the main site of attachment of Clavella adunca changed gradually from the wall of the branchial chamber to the primary rakers of the first gill arch. Vertebral counts suggest that the whiting which enter the Inner Bristol Channel and Severn Estuary are not representatives of the populations found in the Irish Sea.

A hypothesis about the biogeography of Isistius brasiliensis in the north-eastern Atlantic is formulated through the study of frequency, size and geographic distribution of crater wounds, produced by this shark on swordfish (Xiphias gladius) and other large pelagic vertebrates. The results suggest that the bulk of the population of adult I. brasiliensis is found between 11° N and 16° N. Probably there are nursery areas in more southern latitudes. Large individuals would be frequent northwards of 16° N parallel.

Fourteen specimens of the hepatopancreas of the Pacific white shrimp, Penaeus vannamei, were prepared for examination with the transmission and scanning electron microscopes and with the light microscope. The histology and ultrastructure of this organ is similar to that seen in other Decapoda. At the ultrastructural level, it was observed that B-cells rupture at approximately the level of gap junctions located on the lateral plasma membranes of the cells, and discharge the contents of their large vacuoles into the intercellular space. This efflux of enzymatic material may be the mechanism by which cells are released from the wall of the tubule at the proximal end: the rupture and collapse of a B-cell may be analagous to the removal of the keystone which supports an arch. Deprived of support, and lacking structural adaptations for cohesion (there are no desmosomes or interdigitations in the epithelium) and with the intercellular material digested, the remaining intact cells collapse into the lumen of the tubule. The lysis of individual cells of all types - R-, F-, and B-cells - may contribute to the tubules’ total complement of digestive enzymes.

Natural spawning of laboratory-held populations of Pholoe minuta occurred in synchrony with wild populations in Galway Bay. Larval development is described up to an age of 14 days using light and scanning electron microscopy. A pelagic planktotrophic larval phase (4-segment metatrochophores) was observed. Settled 3- and 4-chaetiger stages are described from meiofaunal benthic samples from the study area. A 3-week larval phase is indicated and the current findings are discussed in the light of existing literature on larval development in Pholoe minuta.

Two species of Lamippidae parasitic in Alcyonium digitatum (Octocorallia) are recorded from Wales and the French Channel coast: Enalcyonium forbesi and E. rubicundum. Both are redescribed. Animals recorded as ‘E. rubicundum’ from Banyuls (Mediterranean) proved to belong to an undescribed species, E. confusum n.sp. The family Lamippidae is divided into two subfamilies: Lamippinae and Linaresiinae.