Spiny dogfish Squalus acanthias and narrowmouth catshark Schroederichthys bivius are the only two shark species commonly inhabiting the Falkland Islands shelf. The present study was undertaken to investigate their feeding habits and possible dietary overlap between the species. The diet of the spiny dogfish was dominated by Falkland herring Sprattus fuegensis and squid Loligo gahi, though it also preyed on a wide range of other fish and invertebrates. Catsharks showed a preference for invertebrates. The diet of both species showed marked variations with season, and ontogenic shifts were also evident. Dietary overlap was minimal in winter (15·4%) and maximal in spring (61·1%), the latter being due to both species preying upon spawning aggregations of S. fuegensis.

The polychaete Capitella capitata (Fabricius) has become well known amongst marine biologists as an indicator of polluted conditions, especially those due to organic enrichment. Reish (1959) mapped zones in a polluted harbour and correlated the presence of C. capitata with the polluted region. Bellan (1967) and Cognetti (1972) drew similar conclusions and Henriksson (1969) describes the species as a bacterial pollution indicator. Pearson (1975) records its presence in areas enriched by pulp mill effluents and Rosenberg (1972, 1973) notes its importance in the pioneer community developing after the closure of a pulp mill.

In spite of the increasing interest in the ecology of interstitial meiofauna (Fenchel, Jansson & Thun, 1967; Gray & Rieger, 1971;Jansson, 1968; Renaud-Debyser, 1963; Renaud-Debyser & Salvat, 1963; Schmidt, 1968,1969) little is known about the seasonal changes that occur in interstitial populations. A number of seasonal studies have been made of groups within the meiofauna–for example, tardigrades (Pollock, 1970) and nematodes (Skoolmun & Gerlach, 1971). However, Schmidt (1968, 1969) provides the only information for a total meiofauna population based on regular sampling over a complete year's cycle.

Jet propulsion in the small siphonophores Chelophyes and Abylopsis was investigated by measuring chamber pressures and thrust exerted in tethered nectophores, and by cinephotography of free swimming colonies. Although of similar design, the two siphon-ophores swim at different speeds, and with very different chamber pressures in the locomotor nectophores. Estimates of drag incurred during swimming, and of the cost of the process in the two forms are discussed.

Intertidal meiofauna were collected from various locations around the Pina Basin, Recife, Brazil. The basin is a shallow restricted environment which receives large quantities of untreated sewage, and is therefore polluted, eutrophic and hypoxic. The meiofauna were identified to major taxa (nematodes, copepods, polychaetes, oligochaetes, turbellarians, gastrotrichs, rotifers, ostracods, acari, and juvenile amphipods and bivalves) and counted. Subsamples of nematodes were extracted and identified to the level of genus. The nematode community structure was typical of organically-enriched intertidal areas world-wide. Various environmental measurements were made, including sediment structure, salinity, dissolved oxygen and biochemical oxygen demand in the overlying water. Of these the latter two were shown to be most closely linked to variation in meiobenthic community structure. A much closer link was shown between variation in nematode assemblage structure, biochemical oxygen demand in the overlying water and gravel content of the sediment.

Ampelisca tenuicornis Lilljeborg, 1855, is a member of a widely distributed genus of benthic tube-dwelling amphipods. Population studies of A. macrocephala Lilljeborg in the Øresund show it to have a generation length of 2 years (Kanneworff, 1965), and A. vadorum Mills off Massachusetts, U.S.A., produces two generations per year (Mills, 1967). A. brevicornis (Costa) in the Mediterranean breeds throughout the year with a generation time of 5–7 months (Kaim-Malka, 1969), but has only one generation per year in Helgoland Bight (Klein, Rachor & Gerlach, 1975).

A comparative analysis on various aspects of the reproductive biology of 7 Sciaenidae family species was done. In addition the reproductive parameters needed for stock assessment models were provided. The research covered the analysis of the duration of the breeding season and the estimation of reproductive variables such as size at maturity, fecundity and spawning frequency. When all species were considered together, some aspects of reproduction were similar, regarding the reproductive strategy; all species are batch spawners with indeterminate fecundity and an extensive reproductive season (approximately six months) except for Pogonias cromis, which showed a more limited spawning season (three months). With regard to reproductive potential, wide differences in fecundity values mainly due to the different sizes attained by each species were observed (range in batch fecundity values between 5000 and 2,800,000 hydrated oocytes). However, when relative fecundity was compared, average values were generally similar, ranging approximately between 150 and 200 hydrated oocytes per female gram. Pogonias cromis is the exception within this group, because the mean relative fecundity ranged between 75 and 98 hydrated oocytes per ovary-free female gram. This difference may be a consequence of the greater oocyte size reached by P. cromis eggs (1100–1400 μm) compared to the rest of sciaenid analysed (750–900).

Further study of the larval crabs of the Plymouth district has resulted in the elucidation of many more life-histories. Amongst these perhaps some of the most interesting are Ebalia and Pinnotheres. These genera, placed by systematists in widely different groups, resemble one another closely in many details in their larval stages and are here purposely described together in order that a comparison may be made.

Analysis of the biological time series of plankton samples collected by the Continuous Plankton Recorder (CPR) in the North Atlantic and North Sea has shown a regime shift in the plankton in this region. Both the distributions of planktonic organisms and their timing of occurrence in the seasonal cycle have changed and these changes appear to reflect global warming. In the North Sea the planktonic larvae of echinoderms have shown a recent dramatic increase in both relative and absolute abundance and their seasonal peak of occurrence has advanced by 47 days. The identity of the echinoderm larvae involved in this change has, however, remained equivocal. The small size of many organisms like echinoderm larvae combined with incomplete taxonomic keys hinders their visual identification and their fragility often means that useful morphological features are damaged during sampling by the CPR. Here, using new molecular methods applied to CPR samples, we show that planktonic larvae of the benthic Echinocardium cordatum dominate the North Sea plankton. We argue that since this species benefits from mild winters and warmer waters their numerical increase in the plankton is consistent with recent climatic changes that appear to be affecting the wider ecology of this region.

Monthly samples of intertidal and near-shore Necora puber were collected over two years from a commercially unfished area around Plymouth (south-west England). A clear reproductive cycle, consistent between the two years, was observed, and relatively high numbers of ovigerous females were found from January to June. Zoeal release was estimated to occur from April to June. Ovigerous females had developing ovaries, indicating that sequential broods occur. During embryonic development, egg volume increased by 109%, and egg loss was significant, accounting for between 14 and 18.5% of initial brood number. Females suffering limb loss showed a further reduced brood size compared to females with a full limb complement. The sex ratio of immature crabs was 1:1, whereas the ratio for mature crabs was biased to males (1.46:1). Two sperm plugs were observed in 90% of early postmoult mature females, but 10% had only one or no plug intact, suggesting their failure to mate successfully. These results are reviewed in relation to the biogeography of N. puber and with reference to the developing fishery in the United Kingdom.

The accumulation of radionuclides by I-group plaice, Pleuronectes platessa L., in the vicinity of the pipe-line of the UKAEA plant at Windscale, Irish Sea, has been studied over a 7–month period. The principal isotope found in the flesh was 137Cs, although 144Ce, 106Ru, and 95Zr/95Nb were also present in the gut contents. The 137Cs flesh levels were examined in conjunction with the fluctuations of this nuclide in sea water, sediment and the gut contents. Of the three major dietary components found throughout the sampling period the calculated intake of 137Cs from food appeared to fluctuate most closely with the Nephtys fraction of the diet, despite its relatively low 137Cs content.

Examination of extracts of tissues of a leatherback turtle, Dermochelys coriacea (L.) (Reptilia: Dermochelyidae) by high-performance liquid chromatography inductively coupled plasma-mass spectrometry has demonstrated the presence of arsenobetaine, arsenocholine and inorganic arsenate in heart muscle and liver, and arsenobetaine and inorganic arsenate in pectoral muscle. Although arsenobetaine was the major form in all tissues, inorganic arsenate and arsenocholine accounted for 50% and 15% respectively of arsenic in aqueous extracts of the liver.

The macrobenthos of the subtidal, mesohaline zone of the Schelde Estuary (Belgium) was sampled in October 1996 and 1997 at 54 and 73 sampling locations respectively. Sediments ranged from silty to very coarse, with the dominant sediment type being silt (33% of all locations). Of the 35 macrobenthic species observed, only seven species occurred in more than 20% of the samples. The polychaete Heteromastus filiformis and Oligochaeta were most common. Multivariate techniques revealed three distinct communities, linked mainly with sedimentological factors: (1) a species-poor (nine species) community with a dominance of the amphipod Bathyporeia pilosa, a low mean abundance and biomass (86 ind m−2, 0.0189 g ash-free dry weight (AFDW) m−2), and a mean median grain size of 215±19 μm (fine sand); (2) a species-rich (22) community, with the small polychaete Polydora ligerica as indicator species, a relatively high mean abundance and biomass (2298 ind m−2, 1.395 g AFDW m−2, oysters excluded), a mean median grain size of 133±41 μm, and also the occurrence of sediments with hard substrates being characteristic for this community; (3) a community with an intermediate species richness (12), abundance and biomass (248 ind m−2, 0.249 g AFDW m−2), with H. filiformis and Oligochaeta as indicator species, and a median grain size of 76±9 μm. In the study area several typical brackish water species were observed (e.g. Polydora ligerica, Corophium lacustre, Gammarus salinus).

Mean total abundance and biomass were very low, and the benthic communities appeared to be under stress, with a dominance of mainly small, subsurface deposit and surface deposit feeding opportunistic species. This is probably a combined effect of both natural physical and human-induced disturbance. Only sediments with hard substrates (e.g. rocks) seems to favour species richness, providing a shelter against physical disturbance.

The physical oceanography of the shallow seas south-west of the British Isles ismuch influenced by the exchanges of waters around headlands between neighbouring areas of the sea. These are

The family Rissoidae comprises 24 British species, occurring, many in great profusion, in both littoral and sublittoral marine habitats. On rocky shores the most prolific species is Rissoa parva (da Costa), which occupies a number of microhabitats, algae in particular, centred on the infralittoral fringe but reaching as high as M.T.L., and may also be found sublittorally off these shores.

Mercury determinations were carried out in mussels (Bathymodiolus azoricus) from three Mid-Atlantic Ridge hydrothermal vents (Lucky Strike, Menez Gwen and Rainbow) and shrimps (Rimicaris exoculata and Mirocaris fortunata) from Rainbow. Among the three hydrothermal vents, mussels of Menez Gwen show the highest levels of total Hg and comparing mussels and shrimps from Rainbow the former show more Hg than shrimps. Mussels from different hydrothermal vents are exposed to different kinds of environment which may result in distinct bioaccumulation processes. Detoxification processes in shrimps are related to the low concentrations found. When compared with coastal species from unpolluted sites, mussels show higher concentrations of total Hg and shrimps lower levels. The methyl-mercury concentrations found were very low, not exceeding the detection limit of the technique.

the uk government's strategy for reducing greenhouse gas emissions to meet carbon mitigation obligations and the wider aims on sustainable development has provided the impetus for a rapid growth in activity associated with offshore renewable energy, particularly offshore wind farms. recently, consents for offshore renewable energy development (ored) were approved in three strategic areas—the outer thames estuary, the greater wash and the eastern irish sea. the scale of the planned developments means that each will have a large environmental footprint and multiple ored will have a cumulative effect on the environment. here we discuss current understanding of ored construction, operation and decommissioning with regard to the potential interaction with elasmobranchs because of the worrying status of elasmobranch populations within the uk coastal zone. based on the likely interactions between elasmobranchs and ored a framework is proposed which aims to promote cooperative initiatives between elasmobranch conservation management and the offshore renewables industry.

Respiration rates during late embryonic development and hatchlings of Octopus vulgaris were measured at 20 °C. Oxygen consumption rates increased suddenly at hatching, in response to the increase in energetic expenditure due to their constant swimming activity by means of jet propulsion. Estimates indicate that hatchlings consumed three times more oxygen than the embryos at late stages. Chemical composition analysis revealed a relatively high nitrogen content (11%) in O. vulgaris hatchlings with an energy content of 1.09±0.03 J mg dry matter−1. Specific oxygen consumption in unfed O. vulgaris hatchlings reached values around 0.18 nmol O2 μg−1 h−1. It was estimated that the oxygen consumption of a medium-size egg mass of O. vulgaris is approximately twice than the oxygen uptake of the respective brooding female.

The detailed anatomy of the noses of Kogia breviceps and K. sima (Kogiidae: Cetacea) is described in greater detail than previously. Probable functions of component parts of the nose are deduced from their geometry and physical properties of the tissues. It is concluded that control of the air making the sound is similar to that found in scottish bagpipes with a single reed, that sounds are produced by air being forced from the vocal valve and is resonated in an unusual chamber having cords and membranes, similar to human vocal cords. It is then reflected by air filled ‘mirrors’ and conducted and intensified through a megaphone-like ‘horn’ which is surrounded by air and contains tissues rich in spermaceti oil. Sound then passes through the melon where, by changes in temperature of the spermaceti oil, it is actively focused and possibly scanned. Thermal properties of Kogia spermaceti oil are described and related to previously made sound velocity and density measurements. The way sound production and reflection can continue while large variations of pressure are experienced during deep dives, is suggested. A structure for controlling the temperature of the melon is described. It is considered unlikely that the spermaceti oil is used for buoyancy control in Kogia. Some comparisons are drawn with Physeter catodon, Xiphius and Tursiops and some implications for research on other cetaceans are outlined.

Studies of the osmotic and ionic responses of the supralittoral rock pool inhabitant Tigriopus brevicornis (Crustacea: Copepoda) showed that this species of orange harpacticoid copepod is an unusually euryhaline osmoconformer. Body fluid osmolalities were 297–3691 mOsm kg−1 over a medium range of 151–3440 mOsm kg−1. Whole body sodium increased from 3·65 to 15·0 μmol Na+ mg DW−1 (dry weight) over the medium range 80–1900 mM Na+. Comparative studies on Artemia nauplii and the prawn Palaemon elegans revealed the characteristic hyper-hyporegulation of both organisms. Body density of T. brevicornis remains greater than that of the external medium over the salinity range 5–100 psu because of changes in body fluid osmolality and body volume. Median body density values for T. brevicornis ranged from 1·0359 g ml−1 in 5 psu (median density of 5psu seawater–1·0017 g ml−1) to 1·0848 g ml−1 in 100 psu (median density of 100 psu seawater=1·0751 g ml−1). Tigriopus brevicornis is principally a benthic forager and needs to remain negatively buoyant over a wide salinity range. Environmental monitoring of five supralittoral rockpools was conducted over a year. Live or dormant T. brevicornis were found in salinities of 4–150 psu; temperatures of −1 to +32°C and oxygen concentrations of 0 to >20 mg l−1. It is probably of advantage to T. brevicornis to be an osmoconformer; it is perhaps energetically efficient for such a small organism (~1 mm) and avoids buoyancy problems at high salinity.