As in other populations of killer whales, Orcinus orca, prey selectivity in the North Atlantic population may indicate behaviourally or ecologically distinct types of killer whales. Some killer whale ecotypes are known to prey on large whales, but the ecological impact of such predation events is unknown. Since killer whale attacks on humpback whales, Megaptera novaeangliae, are rarely witnessed, resultant scars may be used to determine the frequency of non-fatal predatory interactions. Using images from the North Atlantic Humpback Whale Catalogue (NAHWC), we examined humpback whale flukes for the presence of rake marks from killer whales (N = 5040). Scarring frequencies range from 2.7 to 17.4% and differ significantly among five regions of the North Atlantic (Gulf of Maine, Canada, West Greenland, Iceland and Norway). The scarring rate in the Canada region is significantly higher than all other regions, and Norway has a significantly lower scarring rate than all other regions, despite more frequently reported killer whale sightings in that region. Within the western North Atlantic, Canada has a scarring rate nearly twice that of either the Gulf of Maine or West Greenland. These data may reflect differential prey choice among killer whale ecotypes and/or the distribution of specific ecotypes across the North Atlantic basin.

The importance of the blood in crustacean metabolism was first raised by Johnston, Davies & Elder in 1971. Until then the conventional view had been that the crab hepatopancreas had a role similar to that of the vertebrate liver (Vonk, 1960), the blood presumably acting as a carrier of soluble sugars. It has recently been shown, however, that blood tissue holds almost four times the amount of polysaccharide than the hepatopancreas and that glucose is actively incorporated into glycogen in the blood (Johnston & Davies, 1972). Polysaccharides were located in deposits in the haematocytes (Johnston, Elder & Davies, 1973). Many previous studies have shown that the main plasma sugar, glucose, varies widely in concentration and appears very sensitive to the animals physio-logical state (see Hohnke & Scheer, 1970). It would seem, therefore, that glucose metabolism in crabs may be readily modified and that by looking at the effect of a physiological stress (starvation and feeding) on the blood/hepatopancreas system one might get some information on the dynamic relationship between these two organs. Previous work (P. L. Lutz, unpublished) had shown that in Carcinus maenas plasma glucose could fall to negligible values on prolonged starvation.

In work on the biology of Balanus balanoides, use has been made of the method of differentiating the successive year groups by the colour of their shells. The present paper describes the method of doing this, and gives a brief account of the infective penetrative algæ which cause the colouration. The first author (M.W.P.) is responsible for the algological observations, and the second (H.B.M.) for the zoological observations.

Direct measurement of water loss from isolated podia of Luidia ciliaris under the influence of known levels of hydrostatic pressure has yielded a revised value for the permeability of this structure to water, namely 37.4 x 10-8 cm3/cm2.s.cm H2O pressure. The total fluid loss from a 50 g starfish will therefore be of the order of 0.75 ml/h. The mechanism for the replenishment of this fluid is discussed in the light of the traditional role of the madreporite. It would seem that adequate influx of fluid through this structure has not been observed, neither could it be responsible for ‘topping up’ in the case of arms severed from the parent body which still continue to move for considerable periods.

The year 1893 was one of exceptional interest to the marine zoologist. During the first two months Plymouth experienced a continuous succession of heavy gales, but towards the middle of March the winds became lighter, and the sea, which had been running remarkably high outside the breakwater, subsided. From that time onwards till the middle of September we enjoyed six months of the most delightful weather,—a period, with scarcely a break, of calm seas and almost cloudless skies. Under the influence of the great heat the temperature of the Channel waters rose continuously, until in August it had attained a point unprecedented for quarter of a century; and it was of the highest interest to observe the effect of this high temperature, and of the prolonged calmness of the sea, upon the floating population of the neighbouring portion of the Channel. Numbers of semi-oceanic forms which rarely reach our shores arrived in remarkable profusion. In June the tow-nets were crowded with Salps, while towards the latter end of August they were almost choked by masses of living Radiolaria.

The effects of the exposure of two tintinnids (Favella taraikaensis and Eutintinnus sp.) to the toxic dinoflagellate Alexandrium tamarense were studied, using the non-toxic dinoflagellate Scrippsiella trochoidea as a control. The tintinnid F. taraikaensis showed backward swimming and cellular lysis after a few minutes in the presence of the toxic dinoflagellate A. tamarense in high concentration (280–700 cells ml-1). At low concentrations of A. tamarense (30–120 cells ml-1) no swimming alterations were observed, but cellular lysis occurred after 48 hours. No changes in the swimming patterns were observed when Eutintinnus sp. was exposed to either toxic dinoflagellates or cell-free filtrate, or when F. taraikaensis was exposed to cell-free filtrate. However, both tintinnids suffered cellular lysis after 48 hours of exposure. Favella taraikaensis and Eutintinnus sp. remained healthy after preying on the non-toxic S. trochoidea for 48 hours. In selectivity experiments, F. taraikaensis avoided cells of the toxic dinoflagellates during the dark phase. Our results suggest that tintinnids could play a regulatory role when the toxic blooms are initiating and the toxic cell concentrations remain still low in the northern Patagonian gulfs of Argentina. Since tintinnids are affected by substances released by A. tamarense, predation on dinoflagellates would not occur during the peak of the bloom.

A mangrove forest can harbour several macroalgal assemblages growing on pneumatophores, roots, stems and other hard substrates. These algae belong to various genera, most typically Bostrychia, and form a community called the Bostrychietum. This study describes the fauna associated with the Bostrychietum and the effect of emersion time on the community. Seasonal samples were collected from pneumatophores on an island in Araçá Bay in 2012, in two areas, one on the border of the island and one inland. Each pneumatophore was considered a sample. The border samples, with a shorter emersion time, contained a richer algal flora associated with pneumatophores, and fauna with species of varied dietary habits. The inland samples, with a longer emersion time, contained only two algal genera and fauna species comprised mostly of omnivorous amphipods and desiccation-resistant detritivorous species. Macrofauna diversity and richness varied over time and were lower in spring. Therefore, the emersion time of the Bostrychietum and the period of the year affect the community structure, for both the macroalgae and the associated fauna.

The trophic ecology and seasonal changes in the diet of the intertidal hydrozoan Tubularia crocea were studied analysing the enteron contents of hydranths collected each season of the year. The relationship between feeding rate, prey availability, and re-suspension processes caused by tidal currents was also assessed. The most prevalent food items were diatoms and crustaceans. The most remarkable differences occurred during summer, when crustaceans were more abundant than diatoms. Conversely, diatoms were the most abundant prey during other seasons, and they were almost the only prey found during winter. There was no relationship between abundances of primary prey items in the water column and their occurrences in stomach contents. Instead, most prey items consisted of benthic organisms, primarily two species of diatoms (Grammatophora marina and Licmophora abreviatta) and fragments (usually appendages) of the amphipods Caprella sp. and Jassa falcata. Most food items were digested within 4–4·5 hours. The mean number of items captured per polyp per day was determined to be 115·2±19·2 in summer, 93·6±14·4 in autumn, 76·8±21·6 in winter and 199·2±31·2 in spring. Prey biomass (dry weight) polyp−1 d−1 was 5·1 μg in summer, 2·3 μg in autumn, 1·8 μg in winter, and 6·3 μg in spring. These values, in relation to hydranth biomass (55·3 μg; dry weight), were equivalent to a food intake polyp−1 d−1 of 9·3%, 4·2%, 3·2% and 11·5% of its own weight, respectively.

Samples of the squid Loligo forbesi Steenstrup 1856 were obtained from commercial catches and research cruises in the Irish and Celtic Seas from August 1991 until October 1993. Age and growth of L. forbesi were estimated from putative daily statolith growth increment counts and from length-frequency data. Indirect evidence of the daily deposition of growth increments was obtained by counting increments on statoliths from immature female squid from successive monthly modes, during a four-month period when length-frequency growth estimates were high. Female growth estimates from length-frequency analysis (15–30 mm per month) were slightly lower than statolith-based estimates (30 mm per month). Statolith data indicated that both sexes had a life-span of approximately one year and that males grew faster and attained a larger size than females. In both sexes growth was found to be logarithmic over the size range sampled (28–505 mm mantle length). Mean estimated age of mature males and females was 317 and 312 days respectively, with the minimum age at maturity found to be 236 and 241 days. Back-calculations of hatching dates showed an extended spawning season from November to May. Squid hatched in the spring grew faster than those hatched in the autumn and winter. In post-recruit L. forbesi, growth of head, mantle and viscera were approximately isometric with body mass. The digestive gland showed slight positive allometry, whilst reproductive organs showed strong positive allometry.

The flash-stimulated luminescent response (FSLR) of euphausiids is a useful tool for the investigation of their bioluminescent behaviour. This paper describes the investigation of the effects of temperature upon a series of such FSLRs produced in individuals of Thysanoessa raschi (M. Sars) by three stimulations with an electronic photofiash at 20 min intervals. The following parameters of the response were measured: responsedelay, responseduration, the sum of these two {delay + duration) and the proportion of stimulations which produced a response. Initial experiments showed that all response delays were significantly different at 10°C and at 5°C, while second andthird response delays were not different from each other. The effect of a range of temperatures from 0° to 20°C on FSLR delay and duration is described. Regression lines based on the Arrhenius equation were fitted to the results. These showed that all response parameters decreased with increasing temperature, although Q10 varied from — 7.8 in the case of thefirst response delay to — 1.3 in the case of second/third response delay. This difference was the most marked effect of the second stimulation; the third stimulation caused no additional change. Below 10°C the second delay was shorter than the first delay. The independent response parameters were found to be delay and delay + duration. Duration resulted from the interaction of these two. These results are discussed and compared with the interpretation of the results of similar experiments by Kay (1965, 1966) onMeganyctiphanes norvegica.

Iorania concordia gen. nov., sp. nov. (Crustacea: Decapoda) belonging to the family Alvinocarididae is described from the Mid Atlantic Ridge, TAG location (26°09'N 44°50'W). The taxonomic position in the family and distinguishing characters (rostrum, armature of telson, form of first maxilliped) of the new genus are presented, and a possible evolutionary feeding hierarchy within the family is suggested. A key is given to the genera of the Alvinocarididae.

Cytokines are important cell mediators involved in immune responses. Their expression can be modulated by numerous factors, including stress. The aim of this study was to compare cytokine mRNA expression from harbour porpoises exposed to different environments. Blood samples were taken from two healthy porpoises living in captivity at the Fjord and Belt Centre Kerteminde, Denmark, and from four wild porpoises accidentally caught in Danish waters. Real-time RT-PCR was used to quantify the transcription of interleukin-(IL)-1β, IL-2, -4, -6, -10, tumour necrosis factor-(TNF)-α, transforming growth factor-(TGF)-β and the acute phase protein haptoglobin. This revealed downregulation of the pro-inflammatory cytokines IL-1β, IL-2, IL-6 and TNFα, and a switch towards the T-helper-cell-(Th)2- and Th3-cytokines, IL-4 and TGFβ, in blood samples of the wild-captured animals. This indicated a shift towards immunomodulatory cytokines. In addition, cortisol levels were increased in the wild-caught porpoises. These results are suggestive of stress-induced modulation of the immune responses in the accidentally caught animals. The current study indicates that the expression pattern of these cytokines and the estimation of the Th1- to Th2- and Th3-cytokine mRNA ratios might be a useful indicator to analyse the influence of stress on the immune system in harbour porpoises.

Trematodes are ubiquitous elements of coastal ecosystems that commonly modify the phenotype of their invertebrate hosts, often with ramifications to higher levels of ecological organization. In this context, trematode infections have been suggested to reduce the consumption of the herbivorous gastropod Littorina littorea (L.) (Mollusca: Gastropoda), in turn affecting the composition of the macroalgal community on which the snail grazes. Here, we examine the effect of two species of trematodes, Renicola roscovita and Himasthla elongata, on L. littorea's consumption in two outdoor microcosm experiments offering the snails two different ephemeral green algae species as a food source. Our results show that, irrespective of the species of parasite and food source, infection decreases consumption: uninfected snails consumed up to 65% more macroalgal biomass than infected snails. Aside from infection status, gender and size also influenced the snails' consumption rate significantly. The differing histopathological impacts of the two species of trematodes on the hosts' gonad–digestive gland complex (in which the parasites reside), suggests that parasitic castration is a likely mechanism for the reduced energy demand of infected periwinkles. Together with existing evidence, our investigation suggests that trematodes in general depress the grazing activity of L. littorea, and that the resulting community regulation occurs throughout the snails' distributional range.

Examination of sampled material and review of the relevant literature revealed the presence of 299 benthic and 46 pelagic amphipod species from the Aegean Sea. Two of the species identified, Caprella hirsuta Mayer, 1890 and Apohyale crassipes (Heller, 1866), are recorded for the first time in the Aegean Sea and the Levantine Basin respectively. A checklist of the Mediterranean amphipods is given, as well as their distribution in the Mediterranean territorial areas and the Black Sea. The faunal comparison of the Mediterranean areas showed that the number of species decreases from west to east. In terms of zoogeographical categories the Atlanto-Mediterranean species dominate in all Mediterranean areas followed by the endemic species concerning the benthic amphipods while in pelagic amphipods cosmopolitan species dominate and are then followed by Atlanto-Mediterranean. Three species, Bemlos leptocheirus (Walker, 1909) and Linguimarea caesaris Krapp-Schickel, 2003, Photis lamellifera Schellenberg, 1928, are lessepsian migrants and are reported in the Levantine and Central Mediterranean Seas.

The diet and predatory behaviour of the nudibranch Roboastra europaea (Mollusca) is described and compared with other nudibranch-hunting opisthobranchs. The natural diet in the Strait of Gibraltar was studied by the analysis of gut contents. Roboastra europaea is a specialist predator of nudibranchs, and the diet is comprised essentially of the polycerids Polycera sp., Polycerella emertoni, Limacia clavigera and conspecific R. europaea. One or several Polycera species appeared as the most dominant prey.  The complete assemblage of potential prey of this predator—the fundamental diet—was assessed in laboratory trials that included all likely prey groups. This predator consistently rejected both non-nudibranch species and non-polycerid nudibranchs. Roboastra europaea is exclusively a predator of polycerids and previously unencountered polycerids are also potential prey items.  As most of the hunter opisthobranchs, R. europaea exhibited cannibalistic behaviour, to the extent that aggressiveness prevailed over mating in intraspecific encounters. Roboastra europaea as prey showed a complex result in laboratory trials: (a) if one individual was small enough complete ingestion proceeded; (b) if there was not enough difference in size, a cannibal attack proceeded, but if ingestion was not possible, it could result in mating behaviour.

Distributions of deep-sea fish, benthic invertebrates and the effects of deep-sea bottom trawling were studied based on data collected in 2005 from a joint collaboration survey undertaken between the Spanish Institute of Oceanography and a deep-sea trawler on the Hatton Bank (north-east Atlantic). A total of 163 valid bottom trawl hauls (600–1600 m) were analysed. The main trawlable grounds were located on the sedimentary seabed of the western flank of the bank (Hatton Drift). Grenadiers and smoothheads were predominant in the trawl catches (67% and 11.8% by weight respectively). Both species were abundant along the western flank. Deep-water sharks accounted for 7.4% of weight, and were abundant along the south-eastern slopes. Chimerids, lotids, morids and other deep-sea species were also taken as by-catch. Grenadiers and deep-water sharks dominated the discards. By-catches of cold-water corals were generally associated with the rocky outcrop and were more abundant at the top of the bank. Abundant by-catches of large sponges, characteristic of sponge-dominated biotopes, were taken from the eastern flank.

The crescent shaped Mascarene Plateau (south-western Indian Ocean), some 2200 km in length, forms a partial barrier to the (predominantly westward) flow of the South Equatorial Current. Shallow areas of the Mascarene Plateau effectively form a large shelf sea without an associated coastline. Zooplankton sampling transects were made across the plateau and also the basin to the west, to investigate the role the partial interruption of flow has on zooplankton biomass and community structure over the region. Biomass data from optical plankton counter (OPC) analysis, and variability in community structure from taxonomic analysis, appear to indicate that the obstruction by the plateau causes upwelling, nutrient enrichment and enhanced chlorophyll and secondary production levels downstream.  The Mascarene Basin is clearly distinguishable from the ridge itself, and from the waters to the south and north, both in terms of size-distributed zooplankton biomass and community structure. Satellite remote sensing data, particularly remotely-sensed ocean colour imagery and the sea surface height anomaly (SSHA), indicate support for this effect. A correlation was found between OPC biovolume and SSHA and sea surface temperature (SST), which may indicate the physical processes driving mesozooplankton variability in this area. Biomass values away from the influence of the ridge averaged 24 mg m−3, but downstream of the ridge biomass averaged 263 mg m−3. Copepods comprised 60% of the mean total organisms. Calanoid copepod numbers varied considerably between regions, being lowest away from the influence of the plateau, where higher numbers of the cyclopoid copepods Oithona spp., Corycaeus spp. and Oncaea spp., and the harpacticoid Microsetella spp. were found.

The allometric relationships between shell length and shell breadth, shell height, shell weight, wet tissue weight and dry tissue weight are described for a population of Cerastoderma edule living at a high tidal level in the Dovey Estuary, West Wales. Seasonal fluctuations in standard animal values for shell weight and dry weight are interpreted in terms of the cycles of reproduction and food availability; the dangers associated with the use of wet weight in growth studies are demonstrated. The population structure is described using a combination of length-frequency and growth ring analyses and comprised nine year-classes with overlapping size ranges. The growth of the population was very slow and the relative growth rate was almost constant; associated with this slow, atypical growth pattern was considerable longevity and a small maximum size. The reasons for these characteristics are discussed.

Certain diatoms seem to live predominantly on the foreshore. While the pelagic diatoms have received very much study, relatively little attention has been given to the shore forms. There is no satisfactory account of these organisms as they occur on the coasts of Lancashire and Isle of Man, and one may expect that they have much importance as the food of many animals. In a further paper I will deal with this question. For this reason I deal here only with those littoral diatoms found along the Mersey Beach, in the vicinity of Liverpool, and with those collected from the sandy and rocky shore of Port Erin (Isle of Man). Masses of these organisms can easily be recognised with the naked eye, discolouration of the sand and mud being due mainly to them, together with some species of desmids and dinoflagellates.

During a study of the reproductive cycle of a subtidal population of Chaetozone setosa Malmgren at an 80 m station off the Northumberland coast (Christie, 1981), the discovery of morphological and reproductive differences in an intertidal population lead to an extended comparative study of three Northumberland populations. The two additional populations chosen for comparison are situated at Low Newton by the Sea and Holy Island, Northumberland. All three populations are located within a maximum distance of 65 km from each other which makes these populations very close on a geographical scale.