We redescribe Imajimaea draculai based on newly collected specimens from the Swedish west coast and describe for the first time its association with the sea pen Funiculina quadrangularis. We assess the phylogenetic position of I. draculai within Autolytinae using nuclear 18SrDNA, together with mitochondrial COI and 16SrDNA, and we estimate its intraspecific variation using nuclear ITS and mitochondrial COI. Our molecular data unequivocally show that I. draculai belongs to the tribe Procerini in a clade consisting of Procerastea, Virchowia and Imajimaea that is separated from all other Procerini taxa for which molecular data are available. No intraspecific variation is found in I. draculai for the sequenced molecular markers.

The ecological value of the stranding record is often challenged due to the complexity in quantifying the biases associated with multiple components of the stranding process. There are biological, physical and social aspects that complicate the interpretation of stranding data particularly at a population level. We show how examination of baseline variability in the historical stranding record can provide useful insights into temporal trends and facilitate the detection of unusual variability in stranding rates. Seasonal variability was examined using harbour porpoise strandings between 1992 and 2014 on the east coast of Scotland. Generalized Additive Mixed modelling revealed a strong seasonal pattern, with numbers increasing from February towards a peak in April. Profiling seasonality this way facilitates detection of unusual variations in stranding frequencies and permits for any change in the incidence of strandings to be quantified by evaluation of the normalized model residuals. Consequently, this model can be used to identify unusual mortality events, and quantify the degree to which they deviate from baseline. With this study we demonstrate that a described baseline in strandings allows the detection of abnormalities at an early stage and can be used as a regional framework of reference for monitoring. This methodology provides means to quantify and partition the variability associated with strandings data and is a useful first step towards improving the stranding record as a management resource.

INTRODUCTION

The nauplius stages of many barnacle species have been described at the light microscope level (Bassindale, 1936; Knight-Jones & Waugh, 1949; Costlow & Bookhout, 1957; Karande, 1974), including those of the British barnacles Balanus balanoides (L.) andBalanus hameri (Ascanius) (Crisp, 1962a, b). Although these studies have included full descriptions of limb structure, it is not possible with the light microscope to resolve the topographical relationship of the limbs and other structures associated with feeding. Attempts to describe the feeding process of barnacle nauplii (Lochhead, 1936; Norris & Crisp, 1953; Gauld, 1959; Moyse & Knight-Jones, 1967) have necessarily been limited for this reason.

Colloidal ferric hydroxide flocculates in sea water, the less rapidly the greater the dilution. When formed in the presence of very small quantities of various emulsoids, it does not flocculate on adding to sea water or flocculates less rapidly.

Sponge samples were taken by SCUBA diving from four sites around Stanley and nine sites at the Jason Islands in the Falkland Islands. Twelve new species are described: Iophon pictoni sp. nov., Lissodendoryx (Ectyodoryx) jasonensis sp. nov., Phorbas ferrugineus sp. nov., Phorbas shackletoni sp. nov., Myxilla (Styloptilon) acanthotornota sp. nov., Amphilectus fleecei sp. nov., Amphilectus dactylus sp. nov., Mycale (Aegogropila) nodulosa sp. nov., Scopalina erubescens sp. nov., Scopalina bunkeri sp. nov., Amphimedon calyx sp. nov. and Pachychalina erinacea sp. nov. Information is also provided on the distribution and external appearance of other sponge species: Iophon proximum Ridley, 1881, Clathria (Dendrocia) tuberculata Burton, 1934, Tedania (Tedania) mucosa Thiele, 1905, Tedania (Tedania) murdochi Topsent, 1915, Halichondria (Eumastia) attenuata Topsent, 1915, Siphonochalina fortis Ridley, 1881 and Haliclona (Soestella) chilensis Thiele, 1905. The biogeography of the Falklands' sponge fauna is discussed.

Gelidium pristoides dominates the lower and mid-eulittoral zones of rocky shores in the eastern Cape, South Africa. A disproportionately high percentage of the plants is attached to barnacle and limpet shells, or restricted to rock crevices. Our experiments at Port Alfred indicate that this distribution is caused by grazing by the limpet Patella oculus and/or strength of attachment of the plants to the different substrata. Exclusion of limpets caused an approximately four-fold increase in the cover of G. pristoides on rock, and an increase from almost 0 to 80% cover on sterilised (dead) limpet shells. Measurements showed G. pristoides to be more than 50% more strongly attached to barnacle and limpet shells than to rock. The distribution of G. pristoides on the various substrata is largely determined by limpet grazing and possibly the different strengths of attachment to the different substrata. The upper distribution limit of G. pristoides is set by physical effects of emersion and was largely unaffected by limpet exclusion. Competition with other algae is important in setting the lower limit: in the sublittoral fringe, although limpet exclusion enhanced recruitment, juveniles were later displaced by articulated corallines, and adult transplants senesced because of encrusting coralline epiphytes.

Variability in the distribution and abundance of the plankton of the western English Channel has been investigated in relation to the hydrography of the region by surveys using the Continuous Plankton Recorder (CPR) (Hardy, 1939) and the Undulating Oceanographic Recorder (UOR) (Aiken, 1981a). Previous surveys in the western English Channel have been restricted in area or in time. Harvey et al. (1935), Holligan & Harbour (1977) and Maddock, Boalch & Harbour (1981) have studied the seasonal succession of the plankton at point stations near Plymouth, with analysis of patterns of seasonal succession and phyto-zooplankton relationships; Boalch, Harbour & Butler (1978) measured primary production at three stations across the western English Channel over a period of eleven years (1964–74); Pingree et al. (1976) have shown that the development of populations of phytoplankton are influenced by the establishment and development of the seasonal thermocline and also frontal regions, both of which are determined largely by tidal streaming.

The reproductive biology of Mediterranean horse mackerel Trachurus mediterraneus was investigated in the Sea of Marmara over a one-year period. Duration and timing of the spawning season, gonad histology, oocyte development and size at sexual maturity were determined. The presence of all stages of oocytes without any distinct size hiatus indicated that oocyte development of Mediterranean horse mackerel is asynchronous with indeterminate fecundity. Spawning starts in May, peaks in July–August and ends in September. Sizes at 50% maturity were found to be 12.2 and 12.5 cm (total length) for females and males, respectively. Mean batch fecundity was calculated as 10136 ± 703 eggs. Our results on the size at sexual maturity and batch fecundity for the Sea of Marmara differed significantly from published results from the Mediterranean Sea. We ascribe these differences to different stock structures in these seas. Our results form the basis for future reproductive biology studies on the under-studied Marmara–Black Sea stock.

The experiments referred to in the following pages were carried out by the wish of the Director at the Plymouth Laboratory, between June, 1912, and February, 1913. They were undertaken with a view to keeping under observation some of the smaller zooplankton, and particularly the Copepoda, in order that they might be followed through the different stages of their life cycle. After a long series of disappointing results, the experiments were unavoidably interrupted at a time when apparently the chief obstacles to success had been located and largely overcome.

In gastropods, variation in shell morphology can be caused by the action of several biotic and abiotic factors. While much of this variation is seen in comparisons between different sites or populations, there is also substantial variation in shell morphology among individuals living side by side. We investigate the effect of trematode parasitism on both intra- as well as inter-site variation in the morphology of the New Zealand whelk Cominella glandiformis. We found that both infection by the trematode Curtuteria australis and site of origin had significant effects on several morphometric dimensions of the snail shell, with some interactions between the two factors. On its own, infection by C. australis accounted for 20 to 60% of the variance in shell morphology, depending on the dimension measured. Infected snails also had smoother shells, with less prominent ridges, than their uninfected conspecifics. Other trematode species, infecting whelks at much lower prevalence, also had impacts on shell morphology, but not necessarily in the same direction as C. australis. Overall, parasitism may be an important factor in explaining intra- and inter-site variation in snail phenotype, with potential repercussions for snail populations and their interactions with other community members.

A collection of 32 specimens of the genus Plakortis (Demospongiae: Plakinidae) from Australia and the Indo-Pacific is here examined. Six species are described, four of which are new to science. Plakortis lita has microrhabds, an irregular tangential ectosomal reticulation, a confused choanosomal skeleton and irregular diods and triods. Plakortis quasiamphiaster has quasiamphiasters (spined diods and triods), spheres and a skeleton with a distinct subectosomal region. Plakortis communis sp. nov. has diods and a tangential ectosomal reticulation with circular meshes; triods and spheres may be present or absent. Plakortis bergquistae sp. nov. has diods in two size-classes, the larger one up to 330–356 µm long, and large triods (actines up to 75–121 µm long). Plakortis fromontae sp. nov. has large diods (up to 220 µm long), rare triods and a double ectosomal reticulation. Plakortis hooperi sp. nov. has diods, triods, microrhabds and spheres, with a confused ectosomal skeleton, a thinly encrusting shape and cream colour. Detailed descriptions of external morphology, skeletal arrangement of the ectosome and spicules in SEM are essential for the taxonomy of Plakortis. The number of valid species in the genus is raised from 15 to 19. A key to Indo-Australian species of Plakortis is given.

Benthic habitat composition is a key factor that structures assemblages of coral reef fishes. However, natural and anthropogenic induced disturbances impact this relationship. This study investigates the link between benthic habitat composition and fish functional groups in four countries in the Western Indian Ocean (WIO). Benthic composition of 32 sites was quantified visually from percentage cover of hard and soft corals, rubble, turf, fleshy and crustose coralline algae. At each site, abundance of 12 coral-associated fish functional groups in 50 × 5 m transects was determined. Cluster analysis characterized reefs based on benthic cover and revealed five habitat types (A, B, C, D and E) typified by decreasing cover of hard corals, increasing cover of turf and/or fleshy algae and differences in benthic diversity. Habitat type A was present in all four countries. Other habitats types showed geographic affiliations: notably Comoros sites clustered in either habitats B or E, northern Madagascar had B, C and D type habitats, whereas sites in central Tanzania and northern Mozambique had habitats D and E. Fish functional groups showed significant linkages with some habitat types. The abundances of corallivores, invertivores, detritivores and grazers were higher in habitat B, whereas planktivores and small excavators showed lower abundances in the same habitat. These linkages between benthic habitat types and fish functional groups are important in informing priority reefs that require conservation and management planning.

The study aims to provide the first detailed account of the diversity and composition of the community associated with biogenic reefs formed by serpulid worms. Ten reefs (aggregations of calcareous Serpula vermicularis tubes), spanning a broad size-range, were collected from Loch Creran, Scotland, a Special Area of Conservation designated principally for the protection of its biogenic reefs. Total faunal abundance was strongly linearly related to reef weight, whilst taxon richness exhibited a hyperbolic relationship with reef size. 278 taxa were recorded from the ten reefs, with a reef of 0.1 m2 area supporting 163 taxa and 12756 individuals, which appears to represent considerable augmentation of diversity and abundance for sedimentary areas of the loch where the reefs occur. The reef assemblage was dominated by polychaetes (94 taxa), molluscs (70 taxa) and crustaceans (45 taxa). Species composition varied with reef size, although reefs greater than 25 cm width exhibited relatively little variation. In comparison with other biogenic polychaete habitats, S. vermicularis reefs appear to support a highly diverse community, which exhibits a high degree of similarity with that found in association with aggregations of the horse mussel, Modiolus modiolus. The presence of the Connemara clingfish, Lepadogaster candollei, rarely recorded at such a northerly latitude, on several reefs, indicates that the reef habitat may provide a stronghold for this species at the edge of its biogeographical range.

These notes record the result of work done at the Plymouth Laboratory during the summer of 1926. They deal chiefly with the feeding habits of Nucula, a Protobranch possessing the type of feeding mechanism characteristic of that order, and not found in any other Lamellibranch. During the course of my work I found Vlès' interesting paper on the sense organ of Nucula. After studying the organ, I arrived at a different interpretation of its function from that reached by Vlès.

Diets of the two deep-sea species of Mediterranean oplophorids were studied by the analysis of 244 foregut contents of Acanthephyra eximia and 69 of Acanthephyra pelagica. All the specimens were collected on the deep slope (between 610 and 2261 m) using an OTSB-14 bottom trawl.

The diet of A. pelagica consisted of small mesopelagic fishes (Cyclothone braueri, Myctophidae) and bathypelagic crustaceans (Gennadas elegans, Pasiphaea multidentata, Eucopia hanseni, Meganyctiphanes norvegica, hyperiids). In contrast, A. eximia was an important scavenger, feeding on fish remains. Benthic species (polychaetes, Calocaris macandreae, gastropods, etc.) were also detected in its diet. There was little dietary overlap between the two species. In A. eximia bathypelagic decapods were important only in the diet of large specimens. In small specimens the acquisition of decapod prey was not attributable to active hunting. On the lower slope A. eximia was more detritivorous, and predatory activity was lower. This trend was most distinct in small and medium-sized individuals, which predominate at that level.

The post-larval stages of the bass, Morone labrax (L.), have never been recorded from these waters. From time to time occasional specimens of young fish have been caught in the plankton which had been tentatively assigned to this species on account of their similarity to the drawing given by Raffaele (1888). Now that the post-larval stages of this species have been described and figured by Bertolini (1933, p. 310 and Plate XIX) the Plymouth specimens can be definitely identified as Morone labrax, and the instances of their occurrence put on record.

This study evaluated the decomposition process of leaf litter from the main Brazilian mangrove species Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle. Senescent leaves were collected, dried and placed in nylon bags with different mesh sizes (fine: 2 × 2 mm and coarse: 8 × 8 mm). The bags were distributed over the sediment, and replicates of each species and mesh size were collected periodically over 4 months. In the laboratory, the dry weight of the samples was measured, and the decomposition coefficient (k) for each species and mesh size was obtained over time. All species showed a rapid decomposition rate at the beginning of the experiment, followed by a slower but steady rate of decomposition over time. The rate of leaf litter decomposition was highest in A. schaueriana, intermediate in L. racemosa and lowest in R. mangle. The difference was mainly linked to the activity and abundance of detritivores, together with the different litter quality of the species, which determined their palatability and probably influenced the decomposition process.

The analyses presented in this paper provide evidence that several community metrics and indicators of the inner shelf community in the Cantabrian Sea show response to placement of anti-trawling reefs. Total biomass, species richness, and to a lesser extent, maximum length and percentage of large fish, were sensitive to exclusion of trawling. Density, diversity and average trophic level did not show this sensitivity. The main species profiting from trawl exclusion were seabreams (Sparidae), catsharks and skates (Elasmobranchii), red mullets (Mullidae), gurnards (Triglidae) and John Dory (Zeus faber). Conversely, the main fishery target species (hake, anglerfish and megrim) showed a progressive decrease in abundance during the study period, a pattern which was also shown by their total stock biomass in the totality of the shelf area. Sea urchins, cephalopods and gastropods also increased in relative abundance with trawl exclusion. Reef age was identified as a key factor in reef development. After reef deployments, two periods were identified: (1) a recovery period, in which total biomass increased, mainly as a consequence of the increase in generalist species (e.g. catsharks); and (2) a consolidation period, during which biomass increased again, mainly as a consequence of an increase in specialized stenoic species (e.g. sparids), while biomass of generalist species remained constant or declined.

Etching cells of boring sponges effect the excavation of calcium carbonate substrates by partial chemical dissolution. They are characterized by the same features found in active osteoclasts, the cells which effect bone resorption in vertebrates. These similarities include a region of numerous cell processes and a system of cytoplasmic bodies, vesicles, and vacuoles which are structurally connected with a tubular system and with extra-cellular channels (Pomponi, 1979). An extensive rough endoplasmic reticulum, Golgi complex, and lysosomes indicate that a lysosomal system is operative (Pomponi, 1979). The lysosomal system has been implicated as the primary mechanism in the destruction of calcined tissue by osteoclasts (Vaes, 1968; Hancox, 1972, Gothlin & Ericsson, 1976; Holtrop & King, 1977). Vaes (1968) proposed that acid hydrolases of lysosomes are active in the resorption of the organic matrix of bone.

Throughout a complete year from September, 1915, to September, 1916, sea-water samples were taken regularly two or three times a week from beyond the Breakwater in the region of the Knap buoy, 2½ miles from Plymouth shore, from the surface and at 5 and 7 fathoms, The object was to supplement the existing records from the tow nets as it is well known that a very large amount of material is lost even from the finest nets, as Lohmann has shown exhaustively (1908). So far the only plankton records from this region have been from the tow nets, and a glance at the tables given at the end of this paper will show directly, if compared with those by Gough (1903–7) and Bygrave (1911), also Cleve (1899 and 1900), the great difference in numbers of the smaller forms, or their entire absence from the tow nettings. Again, no actual numerical records have been given from this region. At the same time as the water samples were taken, tow nettings, coarse, medium and very fine, were also secured, and these were regularly examined for comparison.