Metabolic rate is one of the most frequently measured physiological variables and the relationship between oxygen uptake and body mass is one of the most controversial issues in biology. The present study used closed chamber respirometry to compare the oxygen uptake of 32 species of benthic British gastropod molluscs of a wide size-range (from less than 0.001 g to greater than 10 g dry tissue weight). We investigated the effects of body size on the respiratory rate at 10°C to explore the evolutionary and phylogenetically determined patterns of metabolic scaling both among different gastropods groups, and within siphonate and asiphonate caenogastropods. Resting oxygen uptake (O2) increased with body mass (W) with a slope value of 0.6 using both ordinary least squares (OLS) and standard major axis (SMA) where N = 488, over a 6 fold range of body mass. The slopes b of the regression lines relating oxygen uptake to body mass were similar for all heterobranch molluscs and most caenogastropods. Highest mass-specific rates for oxygen consumption were found for the smallest littorinid species. Trophic mode significantly affected the amount of oxygen consumed with higher oxygen uptake in herbivores than other groups, including detritivores and predators. All of the gastropods reduced their oxygen consumption when exposed to declining oxygen conditions; however, about a third of the species exhibited partial regulation at higher oxygen partial pressures. When exposed to 20% normal saturation levels, smaller gastropods respired at approximately 25% of their rates in fully saturated seawater whereas larger species (above 0.1 g dry tissue weight) respired at approximately 35% of the values recorded at full saturation. Our study suggests that a scaling exponent relating O2 to body mass of 0.6 is typical and may be ‘universal’ for gastropods. It is below the 0.75 scaling exponent which has been proposed for ectothermic invertebrates. It is concluded that size does matter in determining the metabolic patterns of gastropods and that the quantity of oxygen consumed and the energy balance of gastropods is affected by activity, food type and exposure to declining oxygen conditions.

The South American fur seal, Arctocephalus australis, was one of the earliest otariid seals to be exploited by humans: at least 6000 years ago on the Atlantic coast and 4000 on the Pacific coast of South America. More than 750,000 fur seals were killed in Uruguay until 1991. However, a climatological phenomenon—the severe 1997–1998 El Niño Southern Oscillation (ENSO)—was responsible for the decline of 72% of the Peruvian fur seal population due to starvation as a consequence of warming of sea-surface temperatures and primary productivity reduction. Currently, there is no precise information on global population size or on the species' conservation status. The present study includes the first bottleneck test for the Pacific and Atlantic populations of A. australis based on the analysis of seven microsatellite loci. Genetic bottleneck compromises the evolutionary potential of a population to respond to environmental changes. The perspective becomes even more alarming due to current global warming models that predict stronger and more frequent ENSO events in the future. Our analysis found moderate support for deviation from neutrality–equilibrium for the Pacific population of fur seals and none for the Atlantic population. This difference among population reflects different demographic histories, and is consistent with a greater reduction in population size in the Pacific. Such an event could be a result of the synergic effects of recurrent ENSO events and the anthropogenic impact (sealing and prey overfishing) on this population.

Hyperiid amphipods are holoplanktonic marine crustaceans that are known as temporary symbionts of different groups of gelatinous zooplankton. The nature and dynamics of these associations are still poorly understood, particularly in deep waters. The mesopelagic and deep-living planktonic fauna off Monterey Bay, California (down to 4000 m) was surveyed using a remotely operated submersible (ROV) and blue-water diving (BWD) between September 2005 and January 2008. In this work we report our observations on a total of 51 symbiotic associations observed in situ (not from zooplankton samples), between hyperiid amphipods and various taxa of gelatinous zooplankton. We present the first information on the symbiotic relations of the hyperiid Vibilia caeca, and we provide data of 34 previously unknown symbiotic associations. The host range was expanded for several widely distributed hyperiid species. These findings suggest that the symbiotic associations between hyperiid amphipods and gelatinous zooplankton in deep waters deserve further study worldwide.

The capture of crabs of the genus Callinectes is one of the oldest extractive activities practised by waterside communities, due to the abundance of brachyurans along the Brazilian coast. The present paper aimed to provide basic information on the population biology of C. sapidus and C. danae during the period of December 2003 to November 2004, in Babitonga Bay, Joinville, Santa Catarina. The size of the first maturation of C. danae was estimated as 7.1 cm in total carapace width for females, and as 8.6 cm for males. Fecundity of the 20 females of C. danae with carapace width from 7.0 to 11.0 cm varied from 618,667 to 811,267 eggs. Fecundity of C. sapidus was higher, with a median of 978,000 eggs per female, but carapace widths in this species were also larger, with the highest frequency of females attaining 19.01 cm on average. In both species, a tendency was observed for the egg mass to increase with size of females. The capture per unit of effort presented the lowest values in summer, while the largest values occurred from March, August and November. A total of 80 males and 117 females of C. sapidus were captured in the four collecting areas, with the largest abundances in Area III (45.18%), followed by Areas II, IV and I. The size of the first maturation of C. sapidus was estimated as 10.2 cm for females and as 9.0 cm for males. Fishing effort was in relative equilibrium for adult stock (males = 58.75% and females = 52.99%) and juveniles (males = 41.25% and females = 47.01%). The largest monthly rates of biomass of C. sapidus occurred from April to November, with a peak of capture in August, without significant differences in the participation of males and females.

The lagoon of El Bibane (Tunisia) is a Mediterranean coastal area that is affected by an increasing human impact. Thus, an estimation of its biodiversity and an ecological quality assessment are very urgent. This study investigates the meiofaunal and nematode communities of the El Bibane lagoon both from a taxonomic and a functional point of view. Nematodes were the dominant group as is common in brackish water systems. The nematode community was made up of 62 genera in 22 families. Xyalidae, Chromadoridae and Cyatholaimidae were the richest and most abundant families. The taxonomic composition and biodiversity of nematodes were comparable to those found in other European and Mediterranean transitional areas. Both meiofauna and nematodes showed a clear subdivision between marginal and central areas. The central stations, represented by fine sediments and higher amounts of organic carbon, seemed to be characterized by low meiofaunal densities, nematode diversity and a strong dominance of 1B and 2B trophic guilds. These trends could be related not only to the grain size and organic load, but also to a possible influence of tidal currents that can transport pollutants in the central area of the lagoon coming from the adjacent coastal areas. Shannon diversity and life strategies are not always in agreement in defining the ecological quality, but an overall worse ecological quality was detected especially at S6. The results of this study are an important starting point for the future monitoring of the potential and actual human impact on the El Bibane area over time.

An account is given of the distribution of certain polysaccharides, lipids and proteins in the tissues of Siboglinum atlanticum, a uni-tentaculate pogonophore collected from depths of 1300–1500 m on the continental slope. The histology of the various glands and cells is described, and the structure and histochemistry of the tentacle compared with that of three multitentaculate species of pogonophores collected from similar habitats.

Esterases hydrolysing a naphthyl acetate and o-acetyl-bromoindoxyl are found in most tissues of Siboglinum after formalin fixation. An eserine-sensitive esterase was present in the dorsal ciliated band, mostly close to the bases of the cilia. An organophosphorus-resistant esterase was widely distributed as scattered particles in the subcuticular region of the epidermis of the tentacle and anterior end. The other tissues, including the epidermal glands, blood vessels, muscles and peritoneum, contained a simple B-esterase which was closely associated with lipid globules; the nerve fibre B-esterase was not associated with lipid and its apparent sensitivity to copper illustrates one aspect of the difficulty of applying mammalian esterase subdivisions to invertebrates. Lipids form the main food reserve, and appear to have a dominant role in the metabolism.

Pogonophores do not possess a gut at any stage in their life, and must take up food through the epidermis, whether or not it is first digested. The epidermal glands do not appear to have any digestive function. The multicellular pyriform glands secrete fibres of chitin and acid mucopolysaccharide, and produce the major part of the tube in which the animal lives. The unicellular glands are of several types, but most of them, apart from some simple mucous glands, appear to take part in tube formation, secreting mucopolysaccharides or mucopolysaccharides and protein.

Dinoflagellate blooms, chiefly of Gyrodiniwn aureolum Hulburt, occurred along the south and south-west coasts of Ireland in August and September 1978 and mortalities of shore animals and of rainbow trout Salmo gairdneri held in sea cages were described from Dunmanus Bay (Parker, 1980). Since May 1978 four rocky shore sites in Bantry Bay and one in Dunmanus Bay have been monitored monthly (Myers, Cross & Southgate, 1978, 1979). At each site a permanently marked transect is monitored, limpet shell lengths are measured in marked quadrats at M.H.W.N., M.T.L. and M.L.W.N. and settlement, growth and mortality of barnacle species are studied on vertical rock faces. Discoloration of the water was observed at all five monitoring sites in August 1978 but no effects on the littoral or sub-littoral fauna and flora were detected (Cross & Southgate, 1980).

In 1979 a reddish-brown discoloration of the water in Bantry and Dunmanus Bays was first observed in early September. Surface water samples taken at the regular sampling sites between 5 and 10 September revealed very high densities of Gyrodinium aureolum. Slight discoloration of the water persisted at Eagle Point until October and at Glengariff Castle until early November. During this period mortalities of shore fauna were observed at four of the regular sampling sites. Highest mortalities were observed at Pointabulloge in Dunmanus Bay. When visited on 8 September many Patella spp. on the transect were either dead or, if alive, could easily be removed. An estimated 75% of Gibbula umbilicalis were lying inverted in rock crevices with partially opened opercula which they could close only slowly.

Although mucus plays many different roles among marine invertebrates, relatively little is known about the link between biochemical structure and function. In the present study we focused on some physical and chemical properties of the polychaete Sabella spallanzanii's mucus such as viscosity, osmolarity, electrical conductivity, elemental composition, the protein and carbohydrate content, the total lipids and fatty acid composition, and polychlorinated biphenyls (PCBs) contamination. Moreover, an antimicrobial activity of the mucus was investigated. The water content of S. spallanzanii mucus was 96.2±0.3%. By dry weight 26±1.2% was protein, 8±0.21% was carbohydrate and only 0.1% lipid, much of the remainder of the dry weight was inorganic (about 65.2%). The estimated PCBs content was <0.005 μg g−1. The mucus of S. spallanzanii exerted a natural lysozyme-like activity and produced in vitro the growth inhibition of Vibrio anguillarum, Vibrio harveyi, Pseudomonas aeruginosa and Candida albicans. The findings from this study contribute to improve the limited knowledge available on the mucus composition in invertebrates and have implications for future investigations related to employment of S. spallanzanii mucus as a source of compounds of pharmaceutical and marine technological interest.

Nautilus can survive for long periods in water of very low oxygen content. Below a PO2 of around 25 mm Hg activity becomes intermittent, with brief periods of jet propulsion punctuating longer (typically 15–20 min) periods at rest. During these inactive periods ventilatory movements cease and the heartbeat slows to one or two cycles of very low amplitude per minute. The onset of an active period is heralded by an increase in heartbeat frequency and amplitude and a resumption of visible ventilatory movements. The large blood volume and very high oxygen affinity of the blood pigment apparently ensure that the animal accumulates sufficient oxygen during the resting intervals to fuel the brief active periods. Recovery, even after prolonged exposure to near anoxic conditions, is very rapid if the animal is exposed to well-aerated water. These capacities are not only related to a strategy of defence by withdrawal but would also allow Nautilus to exploit environments where the low oxygen content might limit competition from most fish and crustaceans. It is argued that a Nautilus-like physiology and behaviour could well have contributed to the success of extinct ectocochleate forms, living in oceans that were, by and large, less well oxygenated than now. The downward extension of oxygen-rich water and progressive elimination of hypoxic regions from the continental shelves during the Mesozoic may have contributed to the extinction of the ectocochleates by opening up the hitherto hypoxic environments, which they were adapted to exploit, to the more strictly aerobic high metabolic rate competitors and predators that eventually replaced them.

Trials were carried out in the Shannon estuary, Ireland, to test the effects of continuous (CPs) and responsive pingers (RPs) on bottlenose dolphin behaviour. In controlled trials, active and control pingers were deployed on fixed moorings, with T-PODs—acoustic monitoring devices to detect cetacean activity. In a separate trial, pingers were deployed from a moving boat which actively located dolphin groups in the estuary, and dolphin behaviour was recorded. In the static trials, overall detection rates of dolphin vocalizations on the T-POD were significantly lower in the presence of active CPs, but this was not the case for RPs. Mean inter-click interval values were longer for click trains produced in the presence of inactive RPs than for active RPs, active or inactive CPs. In boat-based trials, both active CPs and RPs appeared to affect bottlenose dolphin behaviour, whereby dolphins immediately left the area at speed and in a highly directional manner, involving frequent leaps.

Doliolids were found in samples taken with a Continuous Plankton Recorder (CPR) in October 1989 between 55°14'N 03°32'E and 55°20'N 06°13'E during a tow between Newcastle and Esbjerg. Densities were estimated at >100 m−3 for about 112 km of tow. A sub-sample of specimens in sufficiently good condition to be reliably identified were referred to Doliolum nationalis Borgert. Substantial numbers of doliolids were found on a CPR tow between Harwich and Gothenburg which passed through the same area in that month and specimens were found nearer to the Danish coast in November and south-west of Helgoland in December. The distribution of doliolids in CPR samples taken in the North Sea in the last three months of 1989 is shown in Figure 1.

The thin band between growth increments in the shell of Cerastoderma edule is laid down at the end of the period of emersion, when the pH of the mantle and extrapallial fluids are at a minimum of pH 7·0 and 7·2 respectively. The growth increment is formed during immersion when the pH of the extrapallial fluid is 7·5–7·7 and the mantle 7·6–7·8, which is close to that of sea water (pH 7·8).

The Dublin Prawn or Norway Lobster, Nephrops norvegicus (L.), is widely distributed on soft muddy bottoms, usually between 10 and 50 fathoms. It is found as far north as Iceland and the North Cape, is common in the North Sea and off the Atlantic shores of the British Isles, and extends as far south as the coast of Morocco; a variety, v. meridionalis (Zariquiey-Cenarro, 1935) is found in the Mediterranean and Adriatic (see Havinga, 1929, and Heldt & Heldt, 1931, for details of its distribution). Some aspects of the general biology of Nephrops have been dealt with by Höglund (1942) and Poulsen (1946) for Scandinavian waters, and by McIntosh (1904, 1908) and Storrow (1912)for the waters off north-east England. To a large extent all these workers relied on market catches.

1. The barnacles at five localities in the Plymouth area were examined as a check on the general application of observations made previously i n the Isle of Man.

2. The numbers and weights per square metre, and the mean individual weights, are given for a series of tidal levels for each locality.

3. The two “clean-water” localities agree substantially with the Isle of Man, except for the presence here of Chthamalus stellatus.

4. At the three localities where the water is rich in suspended matter first Chthamalus and then Balanus decreases progressively in numbers, but the latter increases very greatly in size, especially at low water.

5. The increased growth rate at low water, where food is abundant, is compared with the similar effect observed in wave-exposed conditions in the Isle of Man.

The spatial patterns of butterflyfish assemblages (Chaetodontidae) were examined within and between five islands of the Ryukyu Archipelago, southern Japan. Despite being the northernmost reef communities in the world and despite the severe natural and human-induced disturbances that have affected them since the 1970s, the coral reefs of the Ryukyu Islands have one of the most diversified assemblages of chaetodontids in the world. A total of 30 species were identified, and species richness per island ranged from 20 to 25 species. On each of the 45 stations prospected, between four and 17 species were recorded, and between 0.75 and 21.75 ind 250 m−2 were counted. Variation in species composition, species richness and abundance between islands was less pronounced than the variation within islands, where assemblages of the major reef environments (i.e. the reef flat, the reef edge, and the reef slope) were distinguished. The highest species richness and abundance were found on the reef slope and the reef edge. Canonical correspondence analysis revealed that depth, substrate complexity, and live coral cover influenced the distribution of chaetodontid fishes. These factors accounted for 20% of the variation in the species data matrix.

There are five common species of wrasse (Labridae) in British coastal waters, two of which are hermaphrodite, (Labrus bergylta Ascanius and Labrus mixtus L.) and three are gonochorists with discrete sexes (Ctenolabrus rupestris) (L.), Centrolabrus exolelus (L.) and (Crenilabrus melops (L)) (Dipper & Pullin, 1979; Dipper, 1981). L. bergylta (Sjolander, Larson & Engstrom, 1972; Potts, personal observation) and L. mixtus (Wilson, 1958; Potts, 1984) lay their eggs in shallow depressions excavated in coarse paniculate substrates often closely associated with sublittoral reefs. Ctenolabrus rupestris, the smallest of the species is most usually associated with sublittoral crevices, and is the only one to produce pelagic eggs despite showing territorial aggression in the spawning season, a behaviour mostly confined to species with demersal eggs. Little is known about Centrolabrus exoletus, but from the striking sexual dichromism at maturity and its association with rocky reefs it may be supposed that it exhibits some form of parental care for the demersal eggs (Potts, 1984). Crenilabrus melops shows parental care of its eggs which are laid in large and complex algal nests, a feature which is common to all this genus (Fiedler, 1964; Quignard, 1966; Potts, 1984). The corkwing wrasse is one of the commonest coastal species which at maturity show sexual dimorphism and dichromism, a feature which led to taxonomic confusion among earlier workers and which is discussed by Potts (1974).

Benthic microalgal communities usually make a major contribution to the primary production of estuaries and shallow seas. Pulse amplitude modulation (PAM) fluorometry was used to investigate the contribution of benthic microalgae to the primary production of the Okhotsk Sea coast and Saroma Ko Lagoon in northern Hokkaido. In general the benthic communities had a relatively high biomass but low photosynthetic activity. This led to estimates of 29·2% and 64·5% for the benthic contributions for the 9 m and 3 m depth sites at Mombetsu and 13·1% for Saroma Ko. Sea ice algae provided the greatest contribution at Saroma Ko.

The locomotory musculature of dogfish is innervated by the segmental spinal nerves. The sensory and motor innervation of the abdominal musculature was studied in a preparation consisting of a strip of the abdominal body wall innervated by the ventral rami of the spinal nerves.

Each ventral ramus consists of two separate nerve bundles which were found to be peripheral extensions of the dorsal and ventral spinal roots. Recordings from the sensory bundles showed that there are few sensory endings in the musculature and body wall of the dogfish. It was possible to differentiate between ephemeral responses produced by cutaneous free-nerve endings and prolonged discharges which were generated by more specialized sensory endings. In some details these endings were found to be unlike either muscle spindles or tendon organs. Further, skinning experiments suggested that these mechanoreceptors lay in the skin or the very outer layers of the myotome.

Histological searching, together with physiological isolation of units, suggested that these receptors were the corpuscular endings distributed sparsely amongst subcutaneous tissue. These endings are apparently the same as those described by Wunderer (1908) in the fins of elasmobranchs.

The stomach contents of seven male sperm whales Physeter macrocephalus (Odontoceti: Physeteridae) from the north-east Atlantic were examined. One animal was stranded on 27 November 1997 near Wassenaar (the Netherlands). Four became stranded the following day, 28 November 1997, on the island of Ameland (the Netherlands); three of these had food remains in the stomach. Samples were also examined from a whale stranded in August 1998 at Bettyhill (Scotland) and one live-stranded in March 1996 at Tory Island, Co. Donegal (Ireland). Finally, a sample of the stomach contents from a whale stranded near Terneuzen (Scheldt Estuary, the Netherlands) in February 1937 was also examined.

All samples consisted almost entirely of cephalopod beaks. Some fish remains were also found in the stomach of the Wassenaar and one of the Ameland whales. The cephalopod prey were mainly oceanic species: Gonatus sp. (probably Gonatus fabricii, Oegopsida: Gonatidae) was the main prey for all the animals stranded in the Netherlands. The specimen stranded in Ireland had consumed a wider range of prey, mainly Histioteuthis bonnellii (Oegopsida: Histiotetuhidae), but also Architeuthis sp. (Oegopsida: Architeuthidae), Chiroteuthis sp. (Oegopsida: Chiroteuthidae), Teuthowenia megalops (Oegopsida: Cranchiidae) and the octopod Haliphron atlanticus (Incirrata: Alloposidae). The fish remains from the Wassenaar whale were saithe (Pollachius virens, Gadiformes: Gadidae), while remains of monkfish (Lophius sp., Lophiiformes: Lophiidae) and an unidentified fish were recorded from one of the Ameland animals.

The stomach contents from a male sperm whale, Physeter macrocephalus, first located floating a short distance off the south coast of Crete were examined. The remains within the stomach consisted almost exclusively of cephalopod mandibles, or beaks, though other material was found including a piece of rigid plastic mesh. Of the beaks found, 1714 were upper beaks and 2178 were lower beaks, that were used to identify the species. A total of seven species was identified, all of which have been previously recorded in the eastern Mediterranean though are rarely caught by man. Of these Histioteuthis bonnellii was found to be the most important species in terms of both weight and numbers. Although it must be borne in mind that the whale may not have followed its normal feeding habits prior to its premature death, an important insight into its prey items can be revealed. This is the first documented account of the stomach contents of a sperm whale from the Mediterranean, and helps to complete a global record of sperm whale diets.