INTRODUCTION

Certain sand-dwelling amphipods occur either in the intertidal or in the sublittoral zone and extreme low-water springs (E.L.W.S.) has been taken as a convenient dividing line between these two habitats. Previous workers have concentrated mainly on one or other of these contiguous regions. General studies of the in-fauna of intertidal sand on the Isle of Man include those of Pirrie, Bruce & Moore (1932), Jones (1948) and Southward (1953). The in-fauna of sublittoral sandy deposits around the Isle of Man has been studied by Jones (1940, 1951, 1956) and Fincham (1969a). However, Mclntyre & Eleftheriou (1968) working at Firemore Bay, Loch Ewe showed that the intertidal and shallow-water sand regions should be regarded as a unit. Faunal distributions were not always discontinuous about E.L.W.S.

In a recent paper, Green & Parke (1974) drew attention to some of the systematic problems posed by benthic members of the Haptophyceae. Particular attention was given to Ruttnera spectabilis Geitler (1942) the type species of its genus, which was shown by the fine structure of the zoids to be a member of the Haptophyceae with a characteristic rudimentary haptonema and not, as had been thought previously, a member of the Chrysophyceae (sensu Christensen, 1962). Attention was also drawn to the close similarities between R. spectabilis and Chrysotila lamellosa Anand (1937) both in the vegetative and motile phases, but no formal taxonomic changes were made pending the completion of the comparative reinvestigation of both these species together with C. stipitata Anand, the type species of the genus Chrysotila (so designated by Bourrelly, 1957).

In this paper, information is presented on green turtle (Chelonia mydas) nesting on Atol das Rocas (Rocas Atoll), north-eastern Brazil. The temporal distribution of nesting events per season, annual number of nests, carapace length of nesting females, clutch size, hatching success, incubation period, internesting interval, clutch frequency, observed reproductive lifespan, and remigration period are reported. The study period included the nesting seasons from 1990 to 2008, but no regular beach monitoring was carried out in 1998 and 1999. Two sorts of methods were applied to the estimation of the annual number of nests in some seasons. Taking into account the estimated annual numbers of nests, the mean annual number of nests in the study period, excluding 1998–1999, was 335 (standard deviation = 139, range = 136–563, N = 17). An analysis of the available data indicates that the average nesting levels at the beginning of the study period (the first five seasons) and at its end (the last five seasons) were roughly the same. The mean curved carapace length of the nesting turtles decreased significantly during the study period, from 115.9 cm in 1990–1992 to 112.9 cm in 2006–2008. Atol das Rocas was established as a federal biological reserve in 1979, but regular sea turtle conservation activities actually started there in 1990. Since that year, the killing of nesting turtles has ceased, nesting activity by the turtles can proceed in an undisturbed fashion, and their clutches can incubate in a protected environment.

The diet of black anglerfish Lophius budegassa is described for the Cantabrian Sea (North Atlantic coast of Spain) from seasonal samples obtained onboard commercial vessels from January 1993 to December 1994. The stomach contents of fish caught on the continental shelf were examined, and differences in the diet in relation to age-class, season and depth were studied. The age-classes were grouped according to a cluster analysis of diet composition. As a result, three groups were obtained: the first two corresponded to juveniles between 2 and 7 years old, and the third one corresponded to adults between 8 and 15 years old. Although Micromesistius poutassou was an important prey for all ages, the youngest black anglerfish fed mainly on small benthic fish. In contrast, large prey species such as Phycis blennoides and Merluccius merluccius were eaten almost exclusively by adults. The diet composition changed during the year. The changes in the diet of black anglerfish older than 3 years were more related to seasonal differences than to between-size differences. These seasonal shifts were mainly marked by the varying importance of Trachurus trachurus and M. merluccius in their diet. Feeding intensity also showed seasonal variations, with a significant decrease in autumn. An indirect effect of depth on the feeding ecology of black anglerfish was also found, since both age and diet composition changed with depth.

Experiments have been made with the marine diatom Nitzschia closterium grown in artificial light with different nitrogen sources.

After the nitrogen source in the medium was exhausted, photosynthesis and cell division continued, the cells becoming nitrogen- and chlorophylldeficient.

On adding a nitrogen source to deficient cells and storing in darkness, synthesis of organic nitrogen, mostly water soluble, proceeded rapidly from ammonium, less rapidly from nitrate and very slowly from nitrite, with which it grows in light as rapidly as with nitrate or ammonium nitrogen.

Possible reasons why nitrate but not nitrite is reduced in the dark are discussed.

Chlorophyll and yellow pigments were synthesized in the dark by nitrogendeficient cells in quantity related to the organic nitrogen synthesized.

Chlorophyll was synthesized in small amount by non-deficient cells which had been growing rapidly before transfer to darkness. Cells contained less chlorophyll when grown in moderately bright than when grown in dim light.

INTRODUCTION

The food and feeding habits of rays (genus Raja) have received more attention than other aspects of their biology. Being nocturnal feeders (Bigelow & Schroeder, 1953), they have been thought to locate food by smell rather than by sight (Steven, 1930, 1947). More recently, the ability of the electric receptors to detect even weak action potentials has been linked with food foraging (Kalmijn, 1966). Wilson (1953) observed that the behaviour of Raja while apprehending prey was similar to that of Torpedo spp. The functional advantages of a ventral mouth as an adaptation to bottom feeding have been stressed by Alexander (1970).

Day (1880–1884) recorded that rays ate molluscs, crustaceans and fish. That the young of Raja clavata, R. montagui (as R. maculata), R. naevus and R. brachyura feed on crustaceans was observed by Clark (1922). Steven (1930, 1932, 1947) confirmed this in a wider age sample of the same species, adding that juveniles which ate amphipods and crangonids later changed to Upogebia, Portunus and Corystes cassivelaunus, whereas the adults were highly piscivorous and sometimes cannibalistic. Both Clark and Steven obtained their fish close to Plymouth. Lazzareto (1964) and du Buit (1969), largely corroborating the above, included polychaetes in the list of food items but specified no differentiation according to size.

Holden & Tucker (1974), recording only presence or absence of food items, studied R. clavata, R. brachyura, R. montagui and R. naevus from a much wider area.

The last of the organisms to be studied in this series was chosen as a representative of the Dinophyceae. The treatment of Prorocentrum micans Ehrenberg has been similar to that of Asterionellajaponica Cleve & Müler ex Gran (Kain & Fogg, 1958 a) and Isochrysis galbana Parke (Kain & Fogg, 1958 b). The present paper includes a discussion of the results for all three organisms in the light of work by previous authors.

The life cycle, seasonal dynamics and production of two populations of Streblospio species (Annelida: Polychaeta), S. benedicti Webster, 1879, from muddy sediments of the Great Sippewissett Salt Marsh (southern New England, USA), and S. shrubsolii (Buchanan, 1890), from muddy areas of the Alfacs Bay (north-eastern Spain), were studied from November 1986 to September 1988. Both species have life-cycles shorter than one year. The American population showed a unimodal distribution most of the year while in the European population polymodal distributions were common. Average density of S. benedicti over the two-year period ranged from 24,086 to 677 individuals m−2 (annual average 4,554). The observed numbers of S. shrubsolii ranged from 65,668 to 2,579 individuals m−2 (average 35,311). The biomass of the American population ranged from 2·1 to 0·04g dry weight m−2 (average 0·5). The values obtained for the European population ranged from 5·9 to 0·1 g dry weight m−2 (average 4·1). Secondary production was higher in the European population (15·65 g dry weight m−2 y1) than in the American population (3·0 g dry weight m−2 y−1). Production to mean biomass ratios were 4·4 y−1 for S. shrubsolii and 5·4 y−1 for S. benedicti. Population densities are compared with previously published data for other Streblospio populations.

In July–August 2004, the Mid-Atlantic Ridge Ecosystems (MAR-Eco) expedition collected Demospongiae (Porifera) from the Northern Mid-Atlantic Ridge (MAR) north of the Azores, between 41°N and 61°N. Demosponges were found at 10 stations, at depths ranging from 753 to 3046 m. Twenty-two species were identified: 17 Tetractinellida, one Polymastiida, one Suberitida, two Poecilosclerida and one Dendroceratida. The study of this material is an opportunity to revise the taxonomy and the North Atlantic distribution of each of these deep-sea species. Some species are particularly rare and poorly known (Tetilla longipilis, Tetilla sandalina, Craniella azorica, Polymastia corticata) and two are new to science: Forcepia (Forcepia) toxafera sp. nov. and Iotroata paravaridens sp. nov. This study suggests that the MAR is not a longitudinal barrier for the dispersal of deep-sea demosponges while on the contrary, the Charlie-Gibbs Fracture Zone (CGFZ) may be a latitudinal border for the dispersal of deep-sea demosponges, due to great depths and currents.

Arenicola marina (L.) is one of the most common members of the outer estuarine sandy and muddy shores. A moderately euryhaline osmoconformer, this polychaete cannot survive in water of less than about 10‰ constant salinity and then only in the Baltic; however, in the outer portions of estuaries, it is not uncommon for the overlying water to be practically fresh at some stages of the tide. Wells (1949b) postulated that parts of the complex burrowing behaviour of the animal prevents irrigation of the burrow with noxious water, but the advantages to the lugworm of its periodic inactivity have never been fully investigated.

It is now well established that there are several species in the group of rough periwinkles inhabiting European rocky shores. The usual consensus agrees on four, namely Littorina saxatilis (Olivi), Littorina arcana Ellis, Littorina nigrolineata Gray and Littorina neglecta Bean. The first two species are particularly difficult to distinguish in the field and have received much attention. Recent work indicates that the ovoviviparous L.saxatilis is a very variable species living in a wide range of habitats (e.g. Janson, 1985) and that, although it is close to the oviparous L. arcana in shell morphology and in genotype, the two are separate species (Ward & Warwick, 1980; Ward & Janson, 1985), and not reproductive morphs of the same species.

The present study had two aims: first to seek among the molluscs of the Plymouth region, one with a heart suitable for the bioassay of acetylcholine and 5-hydroxytryptamine; and secondly, to examine moUuscan nervous tissue for the presence of cardio-regulator substances. Brief reports of some of the results have appeared elsewhere (Welsh, 1953a, 1954a).

The present work is part of an analysis of catches made with rectangular midwater trawls (RMTs) in the North Atlantic at about 20°W and at 60°N, 53°N, 40°N (all in Lu & Clarke, 1975), 30°N (Clarke & Lu, 1974), 18°N and 11°N (Lu & Clarke, 1975). The collections were made for the ecological programme of the National Institute of Oceanography, Wormley, England (now part of the Institute of Oceanographic Sciences).

An account is given of the variations of shape, colour and patterns of surface sculpture of the shells of ovoviviparous, upper-shore periwinkles of the Littorina ‘saxatilis’ speciescomplex from the sea-coasts and estuaries of south-west England. Variations of shell shape derive from the differing geometries of the helically coiled shell cone. The rate of expansion of the cone is constant in each individual shell, but varies in the component shells of a population and (more widely) between one population and another. The area of the shell aperture is a measure of the expansion rate. Samples of ‘saxatilis’ were taken from some 65 localities covering a wide range of shore environments and, whenever possible, at closely comparable tidal levels (the Pelvetia (P) belt/approx. to M.H.W.S.) and aperture measurements made of shells of all lengths from 1–10 mm (age ca. 0·1–2 years). The apertures of pre-emergent shells teased from the brood pouches of mature females, and of ca. 0·4–0·6 mm length, were also measured. Population aperture-size comparisons were founded primarily on subsamples of shells 10 ± 0.5 mm long - the P-10 aperture-size statistic; and the possible adaptive value of aperture (and foot) size variations were sought through matching relationships with varying conditions of wave attack, shore gradient, platform structure and other features, of which assessments were made in the field. Logarithmic plots of the sequences of aperture-size/shell-length measurements of pre-emergent and post-emergent shells show that the cone geometries are genetically determined, and there is some evidence of the adaptive selection of some geometries and ranges of aperture size in preference to others, mostly in the early post-emergent stages of growth

Talitrus saltator, a supralittoral, sand-beach amphipod, exhibits a nocturnal, circadian, locomotor rhythm entrained by the natural photoperiod (nLD). A phase-response curve (PRC) (light pulse: 2h/400 lx) of the free-running rhythm exhibits a conventional shape; steady-state delay shifts of approximately 3·5 h occur in response to light pulses around subjective dusk, with similar advance shifts when exposed to light pulses around dawn. The seasonal variation of the overt expression of the rhythm indicates that entrainment is predominantly non-parametric, while the constant phase-angle difference between the peak of locomotor activity and dawn confirms the latter as the effective field signal for entrainment. The qualitative relationship between the time scale of the PRC and nLD, together with the absence of any seasonal variation in the periodicity of the free-running rhythm (τ), suggests that entrainment occurs through the interaction of phase shifts defined by the PRC, essentially in response to the systematically changing photoperiod.

1. Dead marine diatom plankton was found to undergo rapid oxidation and decomposition when added to fresh sea water. This was measured by oxygen consumption, nitrogen liberation, phosphate regeneration and bacterial multiplication.

2. Living diatoms added to sea water and placed in the dark continued to absorb oxygen; they were rather resistant to bacterial attack.

3. Diatom-rich marine plankton also absorbed oxygen, while the phosphorus was gradually regenerated. The bacteria did not increase in numbers in correspondence with the oxidation of the fresh diatom material.

4. When sea water in which photosynthesis was allowed to proceed for varying periods of time was placed in the dark, rapid oxidation of the freshly synthesized material took place, as indicated by oxygen consumption and phosphate liberation. Although there was a greater number of bacteria in the water in which photosynthesis took place, the oxidation of the fresh diatom material was not accompanied by any large increase in bacteria; in fact a decrease in numbers was frequently observed.

The mortality of the bottlenose dolphin, Tursiops truncatus, on the southern portion of Rio Grande do Sul State coast was investigated based on 914 beach surveys conducted between 1969 and 2006. A total of 188 stranded bottlenose dolphins were recorded during this period, indicating a 1.8M:1F sex-ratio of those animals sexed (N = 79). Mortality was low in calves, high in juveniles and sub-adults and slightly lower than in adults. The overall mortality was clearly seasonal overlapping with higher fishing efforts in the Patos Lagoon Estuary and adjacent coastal areas, where most individuals washed ashore. Analysis of a continuous 14-year long subset (1993–2006) of the data indicated relatively low levels of mortality between 1995 and 2000 and a marked increase between 2002 and 2005 followed by an apparent drop in 2006. By-catch was responsible for at least 43% of the recorded mortality between 2002 and 2006. Juvenile males were more susceptible to incidental catches. Among females, by-catch of adults represented 75%. Results of a potential biological removal analysis suggest that current levels of fishing-related mortality are unsustainable for the small resident population of bottlenose dolphins that inhabits the Patos Lagoon Estuary, and that this population may be declining.

Spatial, seasonal and age-related differences in infection of the cockle, Cerastoderma edule, with the trematode Meiogymnophallus minutus were studied on the Exe Estuary, England. Prevalence of infection was 100% across all samples with mean abundances between approximately 300 and 1000 larvae per host (maximum=4930 larvae). Aggregration of M. minutus in cockles was extremely high (variancermean ratios >100) and increased linearly as abundance increased. Mean abundance was highest in cockles collected from muddy substrates where the average age of cockles was high. In summer, numbers of larvae fell to less than half of spring levels and then increased after infection by a new wave of cercariae in August. Cockles accumulated larvae for up to 2 y but not thereafter, and levels of aggregation fell in the oldest age class. A peaked pattern of mean abundance and aggregation with age may be a result of parasite-induced death of older hosts or may be due to the inability of cercariae to establish in older hosts.

Luidia ciliaris (Philippi) has intraoral digestion and was found to be a selective feeder on echinoderms. In 258 specimens from the Irish Sea, echinoderms occurred in 97·4% of all stomachs containing food and contributed 92% of the food volume (estimated by points method). The most important food items were Psammechinus miliaris, Ophiothrix fragilis, Ophiura albida and Ophiocomina nigra. Ophiocomina nigra did not occur as frequently as would be expected from their availability. Observation in situ revealed that large specimens had efficient escape response to moving Luidia and aquarium experiments showed that O. nigra deprived of their moving ability were readily eaten. However, the Luidia showed clear preference to Ophiothrix fragilis. There was no distinct seasonal difference in the composition of the diet, but a tendency to a minimum feeding activity in May-June, probably connected with the spawning period.

Since 2003, as part of the LIFE project ‘Del.Ta.’ (NAT/IT/000163) a bottlenose dolphin community has been studied in order to assess the impact of increasing boat traffic in the Pelagie Archipelago (Sicily, Italy). During the summer of 2006 and 2008, land-based surveys were carried out at Lampedusa, one of the Archipelago's Islands, at set hours from 6 locations (7 in 2008) in standard weather conditions. Continuous horizon scanning and focal group sampling methods were used to study dolphin presence and behaviour. Dolphin–boat interactions were recorded for each sighting. A total of approximately 559 hours were spent monitoring and 83 sightings were recorded. With regard to the different types of vessels, interaction with sailing boats was always neutral, whereas fast boats caused the interruption of all activities and avoidance behaviour. Positive interaction occasionally occurred with bottom trawling fishing boats. Interactions recorded when fishing and powered engine boats approached within 200 m predominantly resulted in a negative reaction from the dolphins (approximately 70%) and dolphin behaviour was affected in terms of occurrence and patterns. Behavioural analysis showed that the animals reduced the frequency of behaviours related to feeding, social and relaxing activities. The dolphins also increased information-gathering behaviour such as spyhopping. The use of Markovian chain models revealed evidence of disruptions in sub-sequences made up of behaviours often associated with feeding. After boat departures, the animals rarely restarted their previous activity and persistence of this effect could have long-term consequences as a result of non-habituation. Sighting duration also decreased in the presence of vessels. The possible negative long-term effect of the presence of boats may be indicated by the lower mean sighting duration in 2008, when the highest presence of powered engine boats was recorded. In view of the scenario outlined above, local authorities need to enforce the requirement of maintaining a distance of over 200 m away from the animals for all types of boat and also promote regular land-based surveys of vessel impacts for tourist boats and dolphin watching cruises.