The highly restricted ranges of many intertidal invertebrates, and the relative importance of physical and biological factors on settlement and subsequent mortality, have attracted much attention from ecologists. Most workers have concentrated on rocky shore communities, where patterns of zonation are often very clear (for reviews, see Stephenson & Stephenson, 1949, 1972; Southward, 1958; Lewis, 1955, 1961, 1964), whilst few have looked for such effects within saltmarshes (for reviews, see Long & Mason, 1983; Foster, In Press). Since most saltmarsh invertebrates are infaunal, patterns of zonation are not immediately obvious, but may be of particular interest; the influence of tidal regimes on invertebrate ranges may be more precise in sheltered saltmarsh habitats than on rocky shores, where exposure to wave action is a major confounding variable.

Today, three-spined stickleback Gasterosteus aculeatus are the most abundant fish in the White Sea and are close to their historical maximum. Based on observations from 2011–2013, this study reports quantitative and qualitative characteristics of juvenile stickleback diet during periods of active feeding in coastal Zostera seagrass beds. The following planktonic taxa dominated stomach contents: copepods Temora longicornis and Microsetella norvegica, ciliophora Helicostomella subulata. Benthic organisms such as Oligochaetae and Orthocladiinae also played an important role, whereas the literature suggests they were once rare in marine stickleback diets. Consumption patterns depended on fish size, with the most pronounced diet shift taking place as juveniles reached a length of 15 mm, in late August. In larger juveniles the highest correlation between the abundance of food organisms in stomachs and in the sea was observed for Orthocladiinae, suggesting that they are the preferred food. Overall, changes in diet followed changes in the abundance of available food organisms, but food selectivity analysis of planktonic organisms showed that M. norvegica were actively selected by juveniles.

Bioluminescence has been observed in 11 halocyprid ostracod species, and the sites of secretion are described.

Bioluminescence in cypridinid ostracods has been thoroughly investigated (Harvey, 1952). However, since the original suggestion that the edge glands in the carapace of halocyprid ostracods secrete luminescent substances (Claus, 1891), only a single observation has been made confirming this suggestion on Conchoecia curta ( =clausi) (Müller, 1894).

The abundance, composition and metabolic activity of plankton were assessed in the Tribulation zone of the central Great Barrier Reef (16°–17°S). Wet phytoplankton biomass ranged in shallow reef waters from 30 to 70 mg m−3, and from 60 to 270 mg m−3 in the deep lagoon and in the estuarine areas which are dominated by pico- and nano-algae. Wet bacterioplankton biomass varied from 70 to 290 mg m−3. Wet meroplankton biomass was less than 10 mg m−3. Wet daytime mesozooplankton biomass ranged from 100 to 300 mg m−3 in the deep lagoon. In the estuarine area, it reached 400 to 1300 mg m−3and in the shallow inner lagoon of the Low Isles ring reef it varied from 10 to 30 mg m−3. Zooplankton density increased at night and was 3 to 5 fold greater in the deep lagoon, for about 2 orders of magnitude greater over the reef shallows and up to 3 orders of magnitude greater in mangrove habitats, due to the emergence of demersal components from the benthos. The biomass of zooplankton hidden in the benthic substrates during the day reached 10 to 40 g m−2. Pelagic primary production in the deep lagoon varied between 0.2 and 0.5 g C m−2 d−1. A calculation of the energy balance suggests that the basic energy source for heterotrophic plankton production in the deep lagoon is the organic matter exported from surrounding reef benthic communities and from mangroves. The trophic status of coral reef pelagic ecosystem might range from mesotrophic to eutrophic.

Terebellomorph polychaetes are reported from hydrothermal vents and cold seeps collected in the Pacific and Atlantic Oceans. Two new species of Terebellidae, Neoamphitrite hydrothermalis sp. nov. and Streblosoma kaia sp. nov., are described from hydrothermal vents of the western Pacific. These are the first terebellid species described from hydrothermal vents. New records from hydrothermal vents and cold seeps and new geographical records are presented for nine additional species belonging to Ampharetidae, Alvinellidae, Terebellidae and Trichobranchidae. A synoptic table with diagnostic characters for all species of the genus Streblosoma Sars, 1872 is provided. Keys for all terebellomorph species currently known from hydrothermal vents and cold seeps, respectively, are included. Additionally the new combination Neoamphitrite pachyderma (Hutchings & Glasby, 1988) comb. nov. is proposed.

Fertilization success will determine the rate at which a population can expand and is especially important when considering small, establishing or enduring communities. Introduced species frequently fail to establish reproductively functional populations due to strong Allee effects associated with low densities. The native European oyster, Ostrea edulis broods its fertilized eggs in the pallial cavity for a period of 8–10 days before releasing the larvae. It is considered a partial broadcast spawner and was used as a model species to assess the importance of Allee effects such as inter-individual distance on reproductive success. Distances between individual oysters within test plots in areas of known oyster density were used in conjunction with standardized brood size (n larvae g−1 total wet weight) to assess fertilization success. A significant, positive relationship was observed between brood size and oyster density. Oysters with a nearest neighbour ≤1.5 m were found to brood significantly more larvae than individuals with nearest neighbours ≥1.5 m. Therefore, high density sites need to be maintained to ensure the recovery and enhancement of this OSPAR Convention recognized species in decline.

The structure and distribution of the sponge community in five sites and four habitats in Cagarras Archipelago, Rio de Janeiro, Brazil, are described. The archipelago has three major islands (Cagarra, Palmas, and Comprida), and four islets. Qualitative samples were taken by SCUBA diving in the three islands and in two islets, and quantitative samples were taken in Palmas Island only. Cluster analysis using Jaccard's coefficient on qualitative data grouped the two islets (Cagarra Bank and Cagarra Islet), which are more exposed to wave action, and the three islands formed a group of relatively sheltered sites. Cluster analysis using Bray–Curtis coefficient on quantitative data from different habitats in Palmas Island allowed distinction of three groups of samples: overhangs, shallow horizontal surfaces (6 m depth), and vertical walls plus deeper horizontal surfaces (17 m depth). Sponge abundance was greater in overhangs (61·2 ind m−2), which were dominated by Protosuberites sp. and Clathrina conifera. Abundance was reduced in vertical walls (31·1 ind m−2) and deep horizontal surfaces (16·8 ind m−2). Pachychalina sp. dominated the deep horizontal surfaces and Clathrina conifera was dominant in overhangs. Values of Shannon's diversity in overhangs, vertical walls (both with H′=2·1 bits ind−1) and deep horizontal surfaces (H′=1·7 bits ind−1) were moderate and similar, whereas in shallow horizontal surfaces the sponges were both less diverse (H′=0·37) and less abundant (8·5 ind m−2). Shallow horizontal surfaces were dominated by Hymeniacidon heliophila. The reduced species richness of the sponge community in Cagarras Archipelago when compared with other sites in Brazil and elsewhere is probably due in part to the pollution from the city of Rio de Janeiro. Wave action appears to reduce the number of sponge species at a local scale, whereas substrate inclination affects more strongly the species composition and abundance than the diversity of sponges.

Inshore water collected near Plymouth during the late summer and autumn of 1945, after enrichment with nitrate, phosphate and iron, did not support continued growth of a species of Chlamydomonas, of Chlorella, of a Cryptomonad and of two species of Chrysomonads.

The addition of 0-5-2-0 mg. Mn" or Mnv/m.3 allowed vigorous growth and the production of heavy crops. The effect on Chlamydomonas of adding as little as o-i mg./m.3 was apparent.

The growth of Coscinodiscus excentricus varied in waters collected from inshore and from offshore which had been similarly enriched with N, P and Fe. The addition of manganese had only a minor effect.

The addition of other microelements to inshore waters enriched with N, P, Fe and Mn did not affect growth rate of Chlamydomonas. Manganese starvation led to the production of small Chlamydomonas cells.

Manganese starvation caused a resting condition or lag period in Chlorella. A supply of manganese alone was insufficient for recovery; a period of illumination was also required for internal changes to take place before logarithmic growth was resumed.

The addition of manganese was effective when either nitrate or ammonium was supplied as source of nitrogen, in dim, bright, continuous, or discontinuous illumination.

Metabolic products which leached out of the cells into the water during the growth of both Chlorella sp. and of Nitzschia closterium acted as a growth stimulant.

Manganese at great dilution is rapidly 'collected' from solution by Chlorella. During growth this alga abstracts a material proportion from water containing 5 mg. Mn/m.3

Using Chlamydomonas as 'analyst', it was found that added organic detritus, or the corpses of marine bacteria, adsorbed a material proportion of the manganese in sea water containing 1-2 mg. Mn/m.3

Two groups of young herring are found in the Clyde. One, the offshore group, has been identified as Clyde spring-spawned herring; the other, the inshore type, is of unknown origin. The former were caught only occasionally, the latter at fairly regular intervals during their first year.

The two groups are distinguished by differences in size and identified as belonging to different races by vertebral counts. There was no intermixture.

The offshore herring which metamorphosed at the end of May when 40-50 mm. long, reached a length of 90-100 mm. in winter. The inshore fish which were about 50 mm. long in May reached a length of about 130 mm. in winter.

The estuary of the River Crouch, south-east England, as sampled annually by beam trawl between 1987 and 1989, and again in 1992. The aim of an initial transect survey was to describe and quantify the subtidal epifauna at a time of high ambient tributyltin (TBT) concentrations, arising from the use of tin-based anti-fouling paints on the hulls of moored pleasure craft. Subsequent surveys at representative stations sought to examine the progress of any changes with time in animal populations in relation to a decline in concentrations of TBT in the environment, following a ban on the use of tin-based paints for smaller vessels in July 1987.

Six species of naked amoebae, ranging in size from 45 to 3258 μm3, were isolated from benthic sediments of the Clyde Sea area. The number of fluorescently labelled bacteria (FLB) consumed by these amoebae was determined at 5, 10, 15 and 20°C. Consumption rates varied markedly, ranging from 0·2 to 194·7 bacteria h−1 (equivalent to 0·16–155·8 μim3 bacterial biomass). However, only some of these values were considered to be optimal; several of the uptake values were too low to account for the measured growth rates of amoebae. Using the optimal consumption rate data, the mean specific rates increased from 0·042 bacteria h−1 μm3 at 5°C to 0·131 bacteria h−1 μm−3 at 20°C. This is the first study to detail the ingestion rates of a range of bacterivorous marine gymnamoebae.

Otoliths were obtained from Nezumia aequalis, a small macrourid that is widely distributed throughout the Atlantic and Mediterranean—two very different physical environments. Microchemical analysis of the otoliths was carried out using solution-based inductively coupled plasma mass spectrometry of whole otoliths. Significant differences between fish populations were found for concentrations of the elements Li and Sr. Only 54% of the samples were correctly classified by area using discriminant analysis. Otolith samples from the Reykjanes Ridge were most easily distinguished. The results are discussed in relation to trace element concentrations in the waters of the north-eastern Atlantic Ocean and the Mediterranean Sea.

Much discussion has recently taken place over the peridinian described by Bergh (1882) as Diplopsalis lenticula, and certainly three distinct species have severally been designated as the original. As it is a name frequently to be found in the International Plankton lists, it is important that we should be clear as to which species we are noting, and as recent research at Plymouth has shown that all the three are common in the district it seems worth while to investigate them once more. The question is interesting also from the point of view of phylogeny, as in these species we have close relatives of Peridinium proper which seem to indicate the method of evolution of that genus from simpler forms with fewer plates, and from this point of view alone they are well worth study.

Evidence of female preference for dominant males during mating is reported for the rock shrimp Rhynchocinetes typus. Two sexually mature males of different ontogenetic stage were tethered at opposite sides of a large tank. Tethering restricted males from actively pursuing the receptive female but allowed females to choose between males. Surprisingly most (10 out of 11) females first approached the subordinate typus male, but after these initial contacts all females chose the dominant robustus male. Following antennal and corporal contacts of variable duration seven (out of 11) females initiated the mating process with the robustus male, while four females did not initiate mating during the 90 min observation period. The fact that all mating females selected the robustus shows strong female preferences for these males. It is suggested that female preference for large and dominant males is common among crustaceans with sexual size-dimorphism.

Samples of the widely distributed sand goby Pomatoschistus minutus have been investigated genetically from ten localities in the north-eastern Atlantic, North Sea, western Mediterranean and Adriatic Sea. Levels of genetic diversity and differentiation were assessed with starch (SGE) and cellulose acetate (CAGE) gel electrophoresis for 13 enzyme systems. Genetic differentiation between spatial samples points to a reduction or even absence of gene flow between the Adriatic and the other samples, including the western Mediterranean Sea (pair-wise FST=0.37 and 0.32 for SGE and CAGE respectively). The sample from the Adriatic Sea was clearly differentiated from the other samples at the lactate dehydrogenase loci LDH-A* (SGE and CAGE) and LDH-C* (CAGE). Values for genetic differentiation between Venetian and other sand gobies were of the same order of magnitude as between P. minutus and its closest relative P. lozanoi, suggesting allopatric speciation in the lagoon of Venice. At locations outside the Adriatic Sea, the sand goby has the typical features of a marine fish with a high level of gene flow and a low degree of genetic differentiation.

INTRODUCTION

The black scabbard fish, Aphanopus carbo Lowe, is an elongate mid-water trichiurid, which is caught commercially off Madeira, and has been recorded, though infrequently, from British waters (Tucker & Palmer, 1949; Tucker, 1956). Twelve specimens were caught during a recent cruise of R.V. ‘Sarsia’ in the Biscay area (Forster, 1970), and this note reports observations on their behaviour, histology and anatomy, which suggest that these fish are highly specialized for a particular method of catching prey.

Short-term changes in zooplankton community structure and distribution in relation to changes in hydrological features were studied during summer in two distinct areas of Arcachon Bay (France) from July to September 1986. One sampling site was chosen in the northern part of the bay, influenced by oceanic inputs, and the other one in the south-eastern part of the bay, close to an estuarine zone, influenced by the River Leyre's inputs. Three different zooplankton assemblages were identified according to a temperature–salinity gradient: (i) an estuarine assemblage dominated by Acartia bifilosa and Acartia tonsa; (ii) an autochthonous assemblage composed of Acartia discaudata; and (iii) a coastal neritic one composed of Paracalanus parvus, Oncaea venusta and Penilia avirostris. All these latter assemblages remained stable during most part of the study period. However, a brief climatic event (storm event) occurred in mid-August and gave rise to a sharp decrease in temperatures along with significant changes in zooplankton structure and distributions in the bay. The estuarine community vanished and was replaced by the autochthonous community. In the northern part of the bay, the coastal neritic community succeeded the previously observed autochthonous community.  The effect of this brief climatic event was durable since recovery time lasted two weeks with regard to hydrological features and zooplankton communities. In addition, the climatic event also had ecological consequences since it permitted spreading of planktonic organisms from small-localized areas throughout the bay.

The amino acid composition has been investigated in two euphausiids, Euphausia superba Dana and Meganyctiphanes norvegica (M. Sars), and one mysid, Neomysis integer Leach. Protein-bound amino acids show a very considerable degree of similarity: glutamic acid, aspartic acid, lysine, leucine and arginine are predominant in all three crustaceans, and occur in that order of importance. Together they amount to ~ 50% of the total protein hydrolysates. Concentrations of free amino acids show greater differences between the zooplankton species, but taurine, glycine and arginine are very important in all three. Lysine and ornithine occur in fair quantities in both euphausiids, and proline and alanine are moderately important in Euphausia superba and Neomysis integer.

Six juvenile sperm whales were observed visually and acoustically in the confined waters of Scapa Flow, Orkney Islands during March 1993. General visual behaviours observed included slow travelling, head-outs, logging and side fluking but there were no observations of tail fluking within the confines of Scapa Flow. Recordings of the whales' vocalizations through hydrophones revealed a remarkably wide repertoire including clicks, rapid clicks, gunshots, chirrups, creaks, short trumpets, pips, squeals and clangs. Selected examples of these sounds were digitized and analysed as spectrograms. Clicks, rapid clicks, gunshots and clangs all showed a characteristic impulsive broadband signature. Chirrups, short trumpets and creaks were composed of rapid sequences of broadband impulses, although creaks were invariably faint and were difficult to illustrate well. Chirrups, short trumpets and clangs showed strong spectral peaks and pips were particularly unusual sounds with impulsive narrowband signatures composed of harmonically spaced peaks. Squeals exhibited prolonged, narrowband swept frequency signatures often with slight oscillation. All types of vocalization with the exception of clangs were heard from sperm whales during pure observation, minimum disturbance encounters in the field. Two attempts were made to remove the whales from Scapa Flow, the first being an enticement operation to lure the whales to open water with the use of underwater playback of sounds of socializing female sperm whales and the second a shepherding operation to drive the whales with a flotilla of vessels. The enticement operation was unsuccessful but the shepherding operation was successful, although the whales showed considerable reluctance to navigate a narrow channel to the open sea. During the shepherding operation there was a distinct change in the nature of the whales' vocalizations, with clangs predominating over other forms.

Abiotic and biotic aspects of the covering behaviour of the purple sea urchin, Paracentrotus lividus (Echinodermata: Echinoidea) were systematically examined in situ and in the laboratory to analyse potential intra-population differences in the nature of this behaviour. In the field, significant differences in the occurrence of covering behaviour were found between age groups. Smaller P. lividus covered at higher frequencies than larger individuals. Higher proportions of individuals were also observed to cover during afternoon sampling periods. Significant differences in the types of covering material used were found between P. lividus observed in the laboratory and in the field. These findings suggest that the benefits and/or opportunities of covering behaviour may change with size and habitat.