A review is given of the results obtained from upwards of 600 days of current measuring at the Seven Stones lightvessel during 1939–41. From the plotted observations, an attempt is made to deduce the association between the total daily water movement, irrespective of direction, the residual daily water movement or current, and the mean local residual wind.

The average residual water movement over the whole period was 2½ m.p.d. towards east-south-east. Statements made by earlier authors regarding the water circulation in adjacent areas are examined, and reconciliations are suggested where they seem to conflict with this finding.

An endeavour is made to correlate the wind and water movement mathematically.

Recently developed methods allow quantification and examination of point patterns. Understanding patterns of aggregation or regularity of larval recruits at various spatial scales can help in identifying underlying ecological and biological processes determining their distribution. A rocky shore plot (30 cm wide × 100 cm tall) in southern Hokkaido, Japan was cleared each summer. Barnacle (Chthamallus challengeri) recruitment, after a period of approximately 134 days, was recorded using 40 photographs (25 cm2); 8 photographs per 20 cm horizontal band of tidal height, 5 bands total. Barnacle recruits within each photograph were mapped and co-ordinates used to analyse aggregation at scales from 0–2 cm using Ripley's K statistic and neighbourhood density function (NDF) (both models assumed heterogeneity of first-order density). Quadrat density counts at scales from 20–50 cm provided estimates of aggregation using Morisita's standardized index. These analyses showed that barnacle recruits demonstrate ordered spacing up to a distance of 6 mm. From 6 mm to 2 cm recruits show random spacing based on NDF, but ordered distribution based on the Ripley's K statistic. This discrepancy is likely a result of the cumulative nature of the Ripley's K statistic. At larger scales, Morisita's standardized index indicated aggregation. This result may be explained biologically by the trade off between maximizing need for space at small spatial scales, however being constrained by copulation with neighbours, resulting in aggregation at scales larger than the maximum penis length. The observed pattern was consistent among years with different recruitment densities and among tidal levels, indicating site specific characteristics and interspecific interactions may have a larger influence than desiccation stress or density dependence on spacing of recruits.

Diazona is represented in European waters only by Diazona violacea Savigny. It is a compound ascidian forming massive colonies of spectacular size and appearance. In many ways it is the most interesting of all ascidians, for in its adult structure it straddles two commonly accepted orders and in itself is a strong argument against such a division; it is the only oviparous and small egged compound ascidian, two features undoubtedly primitive; and its manner of budding is the simplest and probably is the basic type for the group as a whole. Only fragmentary descriptions of the morphology and reproduction exist, and a more or less complete account of the various stages of the life cycle may be of some value. The family Diazonidae includes, in addition to Diazona itself, the genera Tylobranchion of subantarctic regions, and Rhopalea of Mediterranean and northern waters. In its entirety Diazona appears to link with such divergent forms as Ciona on the one hand and Archidistoma on the other. The fact that Diazona is obtained by dredging in relatively swift offshore waters and lives poorly in an aquarium probably accounts for the existing unsatisfactory state of knowledge of most of its phases. Most of what is known concerns asexual reproduction; and attention has been given, at various times, primarily to the process of regeneration, rather than bud formation, for example by Della Valle (1884), Caullery (1914), Oka (1906) under the name Aphanobranchion, and by Salfi (1926).

The material of the present account was collected at various times in the Plymouth area from the Mewstone and Eddystone grounds.

European lobsters (Homarus gammarus) were sampled from nine sites around the UK coast to determine whether populations could be differentiated on the basis of morphometric variability, and to relate this to depth and indices of population size at each site. Discriminant analysis indicated that exoskeleton damage was the only characteristic that could distinguish males between sites. In contrast, females were distinguished between sites on the basis of variation in exoskeleton damage, claw spines and rostrum teeth, which tended to be positively correlated to indices of population density. This study suggests that female morphology may respond more strongly than male morphology to local selection pressures, albeit in a limited capacity.

Cod (Gadus morhua L.) from the Arcto-Norwegian stock that spawns off northern Norway were caught at various times during their gonadal maturation cycle over a period of 16 months. The ovaries were removed and either fixed for histological work or deep-frozen for the determination of vitamin A compounds.

The ovaries were inactive from June to September. Maturation began in late September-October and fully ripe eggs were present in February-March, the range of sizes being 500-650 /x. After spawning there was a period of resorption and regeneration, until May, followed by the quiescent summer period.

dry matter rose from about 16 to 29%; the total amount of vitamin A aldehyde, vitamin A esters and alcohol, carotenoids and lipids in the ovaries also increased, though the concentrations of the carotenoids and vitamin A esters + alcohol on a dry-matter basis fell. Vitamin A aldehyde was only found in maturing ovaries and in February, just before spawning, the weight ratio of aldehyde to esters + alcohol was about 10 to 1. The other substances were present in resting ovaries. The appearance of aldehyde in the ovaries occurred when there was histological evidence for the onset of vitellogenesis.

Forty-five specimens of Raia montagui Fowler were recently examined for their cestode parasites and twenty-seven of these contained Echeneibothrium maculatum Woodland, 1927, a species which has not been found in any other elasmobranch. In addition to its well-marked specificity to this host there is an indication that E. maculatum prefers to attach itself to a particular region of the intestine. The cestode was not recognized as a valid species by Baylis (1948) and is included as a synonym of E. dubium Van Beneden 1858 in the Plymouth Fauna List (Marine Biological Association, 1957), but Williams (1958a) and Euzet (1959) were not in agreement with these views. For this and other reasons a re-investigation of E. maculatum was undertaken.

Materials And Methods

The specimens of Raia montagui were trawled off Plymouth by R. V. ‘Sula’ during August and September, 1958 and 1959. The rays were kept alive in the large sea-water tanks outside the laboratory and were examined for their cestode parasites as soon as possible, usually within a period of 24 h. This was found to be necessary because elasmobranchs kept alive under these conditions, presumably without food, have shown a strong tendency to lose their intestinal parasites. It is hoped to discuss this phenomenon more fully elsewhere.

The intestines of some of the fishes were removed from the freshly killed hosts and opened with scissors following the course indicated by the arrowed broken lines in Text-figure 2. Having been opened in this manner they could be quickly examined as a flat piece of tissue for their cestode parasites (Text-fig. 3).

The marine gastropod Capulus ungaricus (L.) is found on rocks and shells, and is known often to associate with filter-feeding lamellibranchs, particularly frequenting beds of Pecten maximus (L.), Chlamys opercularis (L.) and Modiolus modiolus (L.). It has also been found on the shells of living Turritella communis Risso (Jones, 1950, unpublished) and on the superior part of the calcareous tubes of Protula intestinum Lam. (Lo Bianco, 1888).

In a previous paper (Smith, 1940b) the chemical changes observed in ocean sea water flowing across the shallow banks on the west coast of Andros Island (Bahamas) were reported. High salinities were produced by evaporation and calcium carbonate was precipitated. From the data obtained under natural conditions a maximum value of the solubility product constant of calcium carbonate in sea water was suggested. There was no reason to believe, however, that this value of the constant represented the true equilibrium conditions, and experiments have since been made in the laboratory with a view to bringing water from these banks into equilibrium with solid calcium carbonate.

On examining a sample of tanaids from the bathybenthos of the Rockall Trough, part of an extensive collection made by the Scottish Marine Biological Association (S.M.B.A), some very thin translucent tubes were noted. In these could be discerned several tanaids, one of which was extremely elongate. These proved to belong to a new genus, the adults of which were even more filiform than Filitanais moskalevi Kudinova-Pasternak, 1973. Scrutiny by the authors of other Rockall Trough samples has resulted in more adult specimens of this remarkable new tanaid being obtained. In this paper it is diagnosed and described, together with a discussion of its biology.

Since MacMunn (1885), the nature and distribution of naphthaquinone pigments in sea urchins have been widely surveyed, and the main findings have been summarized in reviews by Lederer (1952), Fox (1953) and Thomson (1957). Among spinochromes and echinochromes, the most unusual one is the Spinochrome E discovered by Lederer (1952), which is insoluble in ether.

Recently, the author has examined the napthaquinone pigment in the echinoid, Psammechinus miliaris (Gmel.), and has found a similar pigment to Spinochrome E together with other common spinochromes.

The duration of brood development in the introduced crab, Hemigrapsus takanoi in the Oosterschelde, The Netherlands, was compared at three different water temperatures. At 12, 18 and 24°C the females took an average of 32, 11 and 8 days respectively to lay eggs, which took 86, 28 and 18 days respectively to complete development. Five stages of development were identified, with each brood stage comprising a similar proportion of the duration time at different temperatures. The duration of each brood stage was also somewhat proportional to the number of females found carrying each brood stage in the field at the beginning of the breeding season. There appears to be a trigger for the breeding season in H. takanoi in the field at around 15°C above which ovary development begins. The results suggest that an increase in water temperature as a result of climate change may result in an increased net reproductive rate in H. takanoi due to earlier onset of the breeding season and increased number of broods per inter-moult period resulting in population growth. Increased temperatures may therefore lead to increased invasiveness of H. takanoi where it is already present, and range extension into locations where its establishment is currently excluded by unsuitable temperature.

Coastal ecosystems are particularly vulnerable to alien invasions. Regular, standardized, targeted monitoring of coastal areas helps to detect the arrival of non-native species early, identify sites most vulnerable to invasion, and assess potential for further spread. This study quantified the spread and changes in distribution of non-native oyster, Crassostrea gigas, populations around the coast of Ireland. In total 37 sites were surveyed, in areas which either currently or previously harboured cultivated C. gigas, for the presence and abundance of ‘wild’ C. gigas. Wild populations were identified at 20 sites and at four additional sites C. gigas was observed as recently discarded from aquaculture activity. Five of the invaded sites were identified as being highly suitable for a population expansion based on their current population status. Importantly, we also identified individuals of C. gigas and native European oysters, Ostrea edulis, co-occurring within the same shore at five sites. This is the first record to our knowledge of such co-occurrence within Europe. This evidence of co-existing oyster species raises concerns regarding the potential impact of C. gigas on recovering O. edulis populations. In Ireland, however, C. gigas does not typically spread extensively from introduction points, and although self-containing populations exist, they are currently sustained at a much lower density than those observed in other regions such as the Wadden Sea or French Atlantic coasts. We suggest, therefore, that to protect native oyster populations, C. gigas should be eradicated where co-occurring with O. edulis and recommend continuous monitoring of invaded sites.

Latreutes pymoeus is a poorly studied tropical and sub-tropical shrimp species that mainly lives on sea grass beds. Samples were collected from sea grass beds of Inhaca Island, Mozambique, during August 2005 at neap/spring and low/high tides. Specimens were identified, sexed, counted and morphometric measurements were made. Ovigerous females were classified as small (carapace length (CL): 2.7–3.2 mm), medium (CL: 3.3–3.8 mm) and large (CL: 3.9–4.4 mm). Embryo masses were carefully removed from the pleopods with forceps, eggs staged and counted. On average, about 20% more males were found than females (0.64 ±0.25 and 0.56 ±0.28 ind m-2, respectively), but males were significantly smaller (2.25 ±0.32 and 2.60 ±0.47 mm CL for males and females, respectively). At 3.1 mm CL at least 50% of the females found carried embryos in the pleopods. Average (±SD) brood size increased significantly with female length (76 ±18, 133 ±64 and 205 ±61, for small, medium and large ovigerous females). The number of embryos decreased significantly over the incubation period for each size-class of the shrimp. Brood loss from embryonic Stage I to Stage IV for small, medium and large shrimp were 19.8%, 36.5% and 41.8%, respectively. Although an increase in brood loss was observed with increasing shrimp size, senescence did not seem to occur since larger shrimps carried a higher number of embryos and negative allometry was not recorded. Mean embryo volume, in the same development stage, was not significantly different among the small, medium and large shrimp, increasing significantly from 0.014 mm3 to 0.029 mm3 from the first to last embryonic stages.

Polymastiidae (Porifera: Demospongiae) of the Nordic and Siberian Seas are revised and compared with the related species of the North Atlantic based on the morphological data from the type and comparative material and the molecular data from fresh samples. Twenty species from six polymastiid genera are recorded. Two species, Polymastia svenseni from Western Norway and Spinularia njordi from the Norwegian Sea, are new to science. One species, Polymastia andrica, is new to the Nordic Seas and two species, Polymastia cf. bartletti and P. penicillus, are new to the Scandinavian Coast. Distribution of the polymastiids in the North Atlantic and Arctic is discussed and the allegedly wide distribution of Spinularia sarsii and S. spinularia is questioned.

Short-term measures of behavioural responses of cetaceans to tourism operations have been used in many studies to interpret and understand potential long-term impacts of biological importance. The short-beaked common dolphin (Delphinus delphis) is the species most frequently observed in the Azores and constitutes an important component of the marine mammal tourism industry in this region. This study investigated the potential effects of tour boats on the behaviour of common dolphins off São Miguel, Azores, with particular focus on the changes in activity budget and the time required to resume activities after a tour boat interaction. Behavioural data were collected from land using a group focal-follow methodology. Markov chains were applied to analyse control and interaction sequences and to assess behavioural transition probabilities in both scenarios. In the presence of tour boats, dolphins significantly reduced the time spent foraging and increased the time engaged in other high energy activities. Dolphins also took significantly longer to resume feeding after an interaction occurred. The average bout length varied significantly between control and interaction scenarios, with foraging bouts being shorter during tour boats interactions. The results presented have management implications since feeding is a biologically critical activity. Disruption of foraging behaviour could lead to a decrease in energy intake for this population. With cetacean tourism likely to increase in the future, a precautionary approach to issuing new licences is advisable and any expansion would warrant an appropriate monitoring programme.

Two species of bivalves, Cerastoderma glaucum and Abra Ovata, typical inhabitants of brackish waters, were found in Vouliagmeni Lagoon. Seasonal qualitative and quantitative samples were extracted from the different types of the substratum during 1997–1998. Overall, 800 individuals of C. glaucum and 2700 individuals of A. ovata were collected and measured and their population structure studied.

The seasonality of sexual reproduction was studied in two Prochloron-bearing ascidians, Trididemnum cyclops and Lissoclinum bistratum, on a subtropical coral reef off Okinawajima Island, Japan. These colonial ascidians had testes and/or eggs/embryos from spring to summer. Embryos with tails occurred in summer. Whereas many photosymbiotic didemnids are thought to be sexually mature throughout the year in the tropics, sexual reproduction of the same species in subtropical waters may be limited to spring and summer. The subtropical winter may be too cold for gonad formation. A histological study of sexually mature colonies showed no Prochloron cells attached to ascidian larvae in the pre-hatch stage.

Observations of female genital structures using light and scanning electron microscopy in 25 species of Acartiidae (Copepoda: Calanoida) show the presence of paired gonopores and egg-laying ducts with a typical semicircular configuration in all specimens. In the genus Acartiella, there is no seminal receptacle and the external genital area serves as storage site of the spermatophoral products forming an external mass. Unlike in the other acartiids, the genital structures present a complex organization with paired adjacent gonopores and copulatory pores. In almost all the species, the seminal receptacles exhibit characteristic loop-shaped seminal ducts which connect them to the egg-laying ducts. The functional morphology and taxonomic relevance of genital structures are discussed. The present results do not justify the Steuer's subgenus division of the genus Acartia, the very predominant one of the family.

Activity patterns of limpets were studied at two adjacent sites in an Irish sea lough, Lough Hyne, in order to relate timing of activity to physical and biological influences. Activity was suppressed during heavy rainfall, and osmotic stress from dilution appears to have led to increased mortality in transplanted limpets. Activity increased as tides progressed from neaps to springs, and for limpets low on the shore it was enhanced by wave action. It is suggested that lack of activity in calm water may reduce predation pressure from crabs, which caused high mortality in transplanted limpets. Either low relative humidity or dryness of the rock diminished activity of low-water limpets. Differences in feeding activity between low-water limpets and high-water limpets may relate to food supply, since more food was available low on the shore, and the guts of low-water limpets contained more diatoms than those of high-water individuals. Differences between the two sites are at present unexplained but may relate to differences in micro habitats.

Previously unknown in Conus (Mollusca: Gastropoda) and poorly documented in the Australian region, imposex is demonstrated in 80% of females of six Conus species from Rottnest Island, Western Australia. In no case were the effects sufficiently severe to cause sterility, and reproduction appeared normal. Specimens from the same location preserved in 1975 were unaffected. With more than 500 species, Conus is the largest genus of marine molluscs. Because many species are conspicuous, widely distributed, and occur in populations whose past densities are known, they could serve as monitors of artificially induced pseudohermaphroditism and an early warning of future population responses to pollutants in marine environments at low latitudes.