An attempt has been made to give the range and rate of fluctuation of salinity (and, to a lesser extent, of temperature) that organisms experience at various points on the bed of the lower Tamar Estuary and in the overlying water especially near the surface. Such work until now does not seem to have been attempted. The following general facts emerge: On proceeding from high-water mark to low-water mark there is an increase in the range, rate and duration of fluctuation in salinity. Also the upper limit of the salinity range rises very slightly while the lower limit falls by a large amount, i.e. there is a more or less uniform gradient from high-water mark to low-water mark. Near high-water mark the fluctuation is less and of shorter incidence and is distributed over a higher level of the total salinity range (for the intertidal area) than near low-water mark. Owing to stratification, the farther down the intertidal area the (slightly) longer is the duration of the high salinities, especially in winter. At mid-tide mark the fluctuation is very similar to that on the bottom in mid-river, but is of twice the rate.

The Lusitanian toadfish Halobatrachus didactylus (Bloch & Schneider) (Batrachoididae) is a well-known sound producer that has an unusual large acoustic repertoire for fish. This repertoire consists so far of five distinct sound categories: boatwhistles, grunt trains, croaks, double croaks and a mixed grunt–croak call. Sixteen males that spontaneously occupied artificial concrete nests placed in the intertidal zone of the Tagus estuary (Portugal) were recorded over 8 days in June/July 2006. During the analysis of the recordings new sound emissions were found. Long grunt trains that sounded to the human ear like a running engine were heard. These sounds differ from the normal grunt trains by having a lower amplitude, a much longer duration (tens of seconds versus <1 second) and more grunts per call. Other new sound emissions (e.g. triple croaks) were also registered but were heard less frequently. The incidence of the various sound types is given.

A bacteria-free culture of the important centric diatom Skeletonema costatum has recently been established at Millport, and some exploratory nutritional experiments have been carried out with it. S. costatum is a photo-autotroph whose autotrophy is, apparently, limited to cobalamin (vitamin B12).

Details concerning isolation and maintenance of S. costatum differ from those already published (Droop, 1954a, 1955) only in the matter of pH control, a vital factor in the successful culture of this species whose range of tolerance is narrow (pH 7–5–8–5).

In this investigation of the wounds occurring on blue sharks, tooth cuts were found only on females over 180 cm long, supporting the view that they are courtship scars incurred during breeding. However, it seems unlikely that these sharks normally mate in British waters. It is suggested that tooth cuts can provide information on the size at sexual maturity of the blue shark in European seas.

Beds of Modiolus modiolus, in areas of moderate to strong tidal currents, develop into reefs with a relief of wave like undulations 0.09–0.45 m in amplitude and length scales of 6–18 m. Cores taken by diver operated suction sampler were targeted at positions on the ridges and troughs of a reef, in the Irish Sea off north-west Wales, allowing the fauna to be compared between adjoining ridges and troughs. Sessile epifauna was mostly attached to the larger mussels clumped together on the ridges. The crevice fauna and infauna were also nearly three times more abundant on the ridges, but the lists of species were similar from the two sub-habitats. Species richness was higher on the ridges, however, diversity and evenness measures were similar for ridges and trough samples. The Modiolus sub-habitats were found to be distinct from other macrofaunal assemblages in the wider southern Irish Sea. Deposition of faecal pellets in the spatially complex habitat amongst the mussels provided conditions suitable for an infauna more typical of inshore muddy sands enriched by organic matter. The scale of the ridge and trough morphology may increase variability between replicates when grabs are used remotely to sample this type of biogenic feature.

To characterize the ultraviolet (UV) light-absorbing function of the ascidian tunic, the light absorption spectrum was compared in 22 ascidian species collected from tropical and temperate waters. Non-photosymbiotic ascidians (17 species) had transparent tunics transmitting both visible and UV light, or pigmented or opaque tunics equally absorb both UV and visible light. However, a prominent absorption peak around 320 nm was exclusively found in the colonial ascidians hosting the algal symbiont Prochloron sp., and this absorption peak corresponded to absorption of UV-A (320–400 nm) and UV-B (280–320 nm). The UV-absorbing substances were extracted with methanol. They were mycosporine-like amino acids (MAAs): mycosporine-glycine, palythine, shinorine, and porphyra-334. The MAAs are thought to be synthesized by the shikimic acid pathway that does not occur in animals. Since the isolated Prochloron cells contain MAAs, the symbionts are the most possible candidates as the source of the MAAs in the tunic. In Diplosoma virens, the composition of MAAs was different between isolated Prochloron cells and colony residue from which Prochloron cells were extracted.

The attached tube of P. triqueter is described with special reference to the calcareous grating which is usually found inside the posterior end of damaged tubes. An explanation of the morphology of the tube, and of the calcareous grating, is attempted with reference to an account of the mode of deposition characteristic of the worm.

Populations of Carcinus maenas (Crustacea: Decapoda) from an estuary and from the open shore were compared for salinity tolerance and rhythmic locomotor activity. Estuarine crabs were shown to be predominantly green; red and orange individuals were rare within the estuary in contrast to the open shore. Red crabs were less able to tolerate prolonged exposure to low salinity than green crabs. Spontaneous circatidal rhythms of locomotor activity were similar in red and green forms, but red crabs from the open shore reacted earlier, and were more active upon salinity reduction, than green crabs from the estuary which also showed rapid habituation to episodes of salinity change.

Side-scan sonar and underwater video were used to determine the impact of a trawl fishery on an epibenthic community associated with the horse mussel, Modiolus modiolus in a Northern Ireland sea lough. The presence of marks caused by trawl otter-boards on the sediments could be clearly seen using side-scan sonar and changes to the epibenthos are described from the video survey. It is apparent from the side-scan sonar survey that changes have occurred in the structure of the superficial sediments on heavily trawled areas. However, there was no clear indication of temporal changes. The utility of side-scan sonar coupled with GIS techniques to detect temporal and spatial effects is discussed.

Mercury (Hg), cadmium (Cd) and zinc (Zn) concentration were analysed in muscular and liver tissues of two cetacean species, franciscana Pontoporia blainvillei and boto-cinza Sotalia guianensis, in order to compare their contamination levels in northern Rio de Janeiro State, south-eastern Brazil. The cutlassfish, Trichiurus lepturus, which is the preferential prey of the boto-cinza, have also been analysed. Liver tissue always presented higher concentrations when compared with muscle samples for all the studied metals. The boto-cinza showed higher concentrations for all metals in both tissues than in the franciscana, and the only exception was Cd. This result is probably related to the difference in size prey preference of each cetacean. Mercury was the only element that presented significant positive correlations with body length and age in both cetacean species. The cutlassfish showed rising Hg concentrations with weight and total length, suggesting a possible mercury pathway for marine mammals' contamination.

The spatial variation in abundance and composition of subtidal meiobenthos communities was studied in two Portuguese estuaries under distinct degrees of anthropogenic pressure. Samples were collected from 20 sampling stations along both estuarine gradients from freshwater (<0.5) to euhaline areas (>30). Of these stations 11 were located in the Mondego estuary, a system exposed to high anthropogenic stress, and 9 in the Mira estuary, a naturally stressed system located inside the Natural Park ‘Costa Vicentina’ (south-western coast of Portugal).

Total meiobenthos density was higher in the Mira estuary and in both estuaries the community was dominated by nematodes. Among the twelve taxa identified in the Mira estuary, Harpacticoid copepods and Polychaeta were the second and the third most abundant groups respectively. In the Mondego estuary, Polychaeta was the second while Harpacticoid copepods was the third most abundant group in the thirteen total taxa recorded.

Estuarine gradients of salinity, particles size and water nutrients were clearly detected in both estuaries and there was significant spatial heterogeneity in abundance and composition of the subtidal meiobenthos communities along these environmental gradients. Accordingly, three distinct sections were identified in both estuaries: (i) freshwater sections, where total density, and density of nematodes and Harpacticoid copepods reached minimum values; (ii) oligohaline and mesohaline sections, where the total density was low and diversity was poor; and (iii) polyhaline and euhaline sections, where both total density and diversity reached the highest values.

The similar spatial distribution of meiobenthos assemblages in both estuaries suggests that natural stressors may be the major factors controlling the physicochemical conditions that determine meiobenthos community patterns. The mesoscale variability of subtidal meiobenthos density and composition within estuaries (in the order of kilometres) seems to be more important than the variability between estuaries (at the scale of hundreds of kilometres), a common feature in intertidal systems. From the management point of view, these results, based on higher taxa resolution, represent an obvious constraint to the applicability of ecological quality evaluation tools.

South Georgia, an extremely isolated island within the Antarctic Convergence, was covered by an extensive icecap until ~10,000 years ago. In consequence the depauperate intertidal fauna is of recent origin and consists almost entirely of brooders or direct developers which probably arrived as a result of rafting. Environmental conditions between the tidemarks are comparable with northern Norway and Greenland, so the absence of mussels and barnacles is due to isolation from the nearest feasible sources of colonization (the Falkland Islands and Magellan), and not to a hostile environment. Intertidal animals (eight species studied) have median upper lethal temperatures that are positively and linearly related to maximum height of distribution on the shore. Thermal niche width (median upper lethal temperature minus median lower lethal temperature) is also positively correlated with maximum height of distribution on the shore with species below mid-tide level having narrow niches in contrast to species above mid-tide level that have wide niches. There is no relationship between freezing resistance and position on the shore. Salinity and desiccation tolerances were also greater in animal species from the upper shore than in those from the lower shore. In the case of those species also studied elsewhere (Lasaea rubra (Mollusca: Bivalvia); Nacella condnna (Mollusca: Gastropoda) and Tigriopus sp. (Crustacea: Copepoda)), evidence is presented to show that no special adaptation is exhibited by South Georgian animals, and that upper zonation limits are controlled primarily by physical tolerance. This is particularly marked in the case of N. condnna which has similar thermal tolerances on the Antarctic Peninsula, on Signy Island and at South Georgia; in consequence it can only inhabit the extreme lower shore at South Georgia, yet penetrates to mid-tide level at Signy Island.

Despite their economic importance, the ecology of many sea cucumber species is poorly understood and factors influencing their habitat preferences remain largely unexplained. The distribution and habitat preference of two sea cucumber species; Holothuria atra and Holothuria edulis were studied off the north-west coast of Sri Lanka by underwater visual census in October 2008. The relationships between the density of each species and the habitat variables, such as mean grain size, organic content (% of dry weight), gravel (%), silt–mud (%), and depth, were examined using a generalized additive model. All these variables except silt–mud have significant influence (P < 0.05) on the habitat association of H. atra. The shallow water (<10 m) seagrass habitat with sediments characterized by 2–3.5% organic content, 15–25% of gravel and coarse sand (0.7–1.2 mm) were the most preferred conditions by H. atra. High densities of H. edulis were found in the shallow (<10 m) depths of rocky areas with algae and seagrass. Favoured bottom sediment conditions of H. edulis were mainly similar to the conditions preferred by H. atra, except organic content which did not significantly influence the habitat preference of this species. The preference towards the specific habitat characteristics seems to be associated with their feeding and protection. An understanding of habitat preference would be useful to improve the management of these sea cucumber populations and enable more precise stock assessment.

The comparative tolerance and accumulation of the trace metals zinc, copper and cadmium in populations of the littoral polychaete worm Nereis diversicolor from three sites: (a) heavily metal-contaminated Dulas Bay in Anglesey, north Wales, (b) the Blackwater estuary, Essex, as a control site, and (c) West Thurrock, the Thames estuary as a site of intermediate metal contamination, were investigated. Worms from Dulas Bay did not show increased tolerance to any metal, but worms from West Thurrock showed significantly increased copper sensitivity compared to the worms from Dulas Bay and the Blackwater. Worms accumulated zinc and copper from sediments with raised zinc and copper concentrations, and all three metals from solution in proportion to dissolved concentration. Accumulated metal was not excreted in 21 days and field concentrations of zinc and copper in the worms differed between sites. There was no evidence for inter-populational differences in accumulation rates of zinc and cadmium from solution, but worms from Dulas Bay accumulated copper from solution at a significantly higher rate than did worms from the other two sites. Nereis diversicolor takes up and accumulates zinc and cadmium from solution at similar rates per unit molar exposure, but cadmium is taken up at a greater rate per unit free metal ion molar exposure. Although N. diversicolor from Dulas Bay is exposed to very high availabilities of zinc and copper, accumulation and detoxification mechanisms are sufficient to cope with the extra metal influx (accentuated for dissolved copper) without selection for a metal-tolerant population.

A survey of forty-eight species of British marine invertebrates has shown that porphyrins which have not previously been described in these animals are present in three representatives of the Annelida, two of the Mollusca and two of the Echinodermata. The occurrence of protoporphyrin in Asterias rubens was confirmed in a previous paper (Kennedy & Vevers, 1953b). A redfluorescent extract was obtained from the sponge Tethya aurantium, but it contained too little material for further investigation. No trace of a porphyrin was found in the coelenterates, crustaceans and tunicates examined, although Moseley found ‘polyperythrin’ (which MacMunn later identified with the ‘haematoporphyrin’ of Asterias and Arion) in Flabellum and Fungia.

Chlorocruoroporphyrin was found free in the starfishes Luidia and Astropecten. Uroporphyrin was extracted from the soft dorsal integument of Duvaucelia (= Tritonia) plebeia, and from the integument of Aplysia punctata, observations of interest in view of the widespread occurrence of uroporphyrin in mollusc shells.

Coproporphyrin III was characterized from extracts of the viscera of Myxicola infundibulum, Nereis diversicolor and Chaetopterus variopedatus. Evidence of the occurrence of a penta-carboxylic porphyrin was obtained from paper chromatography of the extract from the gut of Chaetopterus.

These findings are discussed in comparison with the distribution of porphyrins in birds and mammals.

The first specimens of Rhabdopleura to be found were dredged by G.O. Sars from a depth of 120 fm (220 m) at Skraaven (Fig. 1) in the Lofoten Islands during 1866. They were mentioned in a fauna list by M. Sars (1868) as Halilophus mirabilis, and fully described by G.O. Sars (1872, 1874) as Rhabdopleura mirabilis. By that date AUman (1869 a-c) had described Rhabdopleura normani. His specimens had been dredged from 90 fm (165 m) off the Shetland Islands in 1868 by A. M. Norman and J. G. Jeffreys. Burdon-Jones (1954) gives the locality more precisely as:lsquo;… a depth of 93 fm at a point in the outer Haaf, some 40 miles east of Whalsey Skerries’ (Fig. 1). In 1880 Hincks described a third species which he named R. compacta because of its distinctive habit of growth. The habitat and locality were somewhat inadequately given as: ‘On shells from deep water; Coast of Antrim’ (Fig. 1). Hincks makes acknowledgement to Hyndman for dredging these shells (Hincks, 1880). From 1857 to 1859 Hyndman was serving on the Belfast Dredging Committee and it is possible that the specimens of R. compacta, which Hincks had discovered in material sent to him by Hyndman many years previously, were among the polyzoan collections known to have been made off the coast of Antrim. Hyndman (1858) included a list of polyzoa identified by Hincks, from deep water near the Maidens' Rocks. The following year Hyndman (1859) included a further list of polyzoa identified by Hincks, for which specific localities are not given.

In an attempt to describe the physical and chemical characteristics of the sediments as an environment for the invertebrate benthos, a total of 273 stations covering the sector from 56° N to 61° N in the North Sea was sampled. The sediment samples which were collected by grab and corer were analysed for particle size (as well as silt-clay content and sorting), organic carbon, plant pigments and trace metals (Cd, Pb, Zn, Ni, Co, Cu). On a smaller scale a few stations were sampled for redox potential, pH and pesticides.

Taking into account the geological history and the on-going hydrographic processes, explanations for the formation of the sedimentary provinces in the North Sea were provided. The sediments were predominantly fine to medium sand, but there was a depth-related gradient with the finer grades, organic carbon and, to a lesser extent, plant pigment being found in the deeper sedimentation basins of the Fladen Grounds and Norwegian Trench.

Trace metals and pesticide contaminants associated with the finer organic and inorganic fractions were higher in the sediments of the above deeper areas as well as in the vicinity of estuaries. It could be concluded that despite the enhanced concentrations of Cd, Ni, Pb and Co, at the east of Shetland, which were due to a geochemical anomaly, there was no evidence of any important or large-scale contamination of the North Sea as a whole.

Traditional ecological knowledge is being increasingly used in wildlife management in northern regions, and Inuit harvesters in Nunavut, Canada, have extensive knowledge about local wildlife species. We collected Inuit knowledge on killer whales (Orcinus orca) through 105 semi-directed interviews in 11 Nunavut communities from 2007 to 2010. Interviewees provided extensive information on killer whale movements, seasonal presence, distribution and abundance in the eastern Canadian Arctic. Observations from different communities were often complementary, and there was consistency in interview comments both within and among regions. Nearly all participants had seen killer whales at least once, and the whales were present every summer (July–September) in all regions, although movements depended on ice conditions. Relative abundance of killer whales varied by region, and they were reported more often in North Baffin communities than in other regions. Killer whales migrated through Hudson Strait and Lancaster Sound following their marine mammal prey. Estimates of local population sizes were variable, with suggested numbers that varied from tens to the low hundreds. Most interviewees in the Foxe Basin, Hudson Bay and north Baffin regions thought that killer whale presence was increasing. In contrast, half the South Baffin interviewees noted declines in past abundance due to the 1977 harvest of 14 whales that became trapped in a saltwater lake. Interviews provided information at a long temporal and wide spatial record. Inuit are reliable observers and continued killer whale research will be most effective if it integrates modern science approaches with the traditional skills, knowledge and experience of Inuit harvesters.

It is difficult to rear crabs from the egg, and few experiments of the kind have been successful. It is intended in these studies of the Plymouth Brachyura to rear as many species as possible from the berried crab, and thus to ascertain without doubt the larvæ of each species in all stages, so that they may be recognisable in the plankton.

The members of the Oxyrhyncha so far observed in the Plymouth district are the following:-

Inachus Dorsettensis (Pennant), Inachus Dorynchus Leach, Macropodia longirostris (Fabricius), Macropodia Egyptia A. Milne-Edwards, Macropodia rostratus (L.), Achæus Cranchii Leach, Maia squinado (Herbst), Pisa biaculeata (Montagu), Hyas araneus (L.), Hyas coarcticus Leach, Eurynome aspera (Pennant).

The aims of this study were to ascertain if individual turbot females show a seasonal decline in their egg-size when kept in conditions of constant temperature, and to relate turbot egg-size to the length and yolk-sac index of the emergent larva. Each female showed a significant seasonal egg-size decline and there was a positive correlation between egg-size and the length and yolk-sac index of the subsequent larva. However, larval length was not related to yolk-sac index, nor was the ratio of yolk-sac index: larval length related to egg-size. The maximum mean egg-size tended to increase with the female's weight and length. The implications of these findings are discussed in terms of the general ecology of turbot and its culture.