Submarine cliffs are typically crowded with sessile organisms, most of which are ultimately exported downwards. Here we report a 24 month study of benthic fauna dropping from such cliffs at sites of differing cliff angle and flow rates at Lough Hyne Marine Nature Reserve, Co. Cork, Ireland. The magnitude of ‘fall out’ material collected in capture nets was highly seasonal and composed of sessile and mobile elements. Sponges, ascidians, cnidarians, polychaetes, bryozoans and barnacles dominated the sessile forms. The remainder (mobile fauna) were scavengers and predators such as asteroid echinoderms, gastropod molluscs and malacostracan crustaceans. These were probably migrants targeting fallen sessile organisms. ‘Fall out’ material (including mobile forms) increased between May and August in both years. This increase in ‘fall out’ material was correlated with wrasse abundance at the cliffs (with a one month lag period). The activities of the wrasse on the cliffs (feeding, nest building and territory defence) were considered responsible for the majority of ‘fall out’ material, with natural mortality and the activity of other large mobile organisms (e.g. crustaceans) also being implicated. Current flow rate and cliff profile were important in amount of ‘fall out’ material collected. In low current situations export of fallen material was vertical, while both horizontal and vertical export was associated with moderate to high current environments. Higher ‘fall out’ was associated with overhanging than vertical cliff surfaces. The ‘fall out’ of marine organisms in low current situations is likely to provide an important source of nutrition in close proximity to the cliff, in an otherwise impoverished soft sediment habitat. However, in high current areas material will be exported some distance from the source, with final settlement again occurring in soft sediment habitats (as current speed decreases).

Recently the influence of an electric light on the capture of the main groups of deep sea animals by a midwater trawl was described and discussed (Clarke & Pascoe, 1985). With regard to fish it was shown that at depths close to 800 m the total number, the total volume, the volume of the ten largest and the volume of the single largest fish all increased significantly when an electric light was used on the headline of the trawl when compared with controls with the light off. These experiments were carried out both in the Bay of Biscay and off Madeira.

Aora spinicornis Afonso is recorded for the first time from the British Isles. Two species of Aora, A. gracilis (Bate) and A. spinicornis Afonso are now known from these waters. A. typica Krøyer, long considered a British and Irish species, is actually known only from the Southern Hemisphere. Figures and diagnoses of both species are provided together with a key to their identification.

Introduction

Lincoln (1979) records one species of Aora Kreyer from British and Irish waters. Due to an oversight (Lincoln, personal communication) he overlooked the paper by Myers (1973) (although listed in the bibliography) and attributed the single species to A. typica Krøyer, a species actually known only from the Southern Ocean between 20° S and 50° S (see Myers & Moore, 1983 which also includes a key to the world species). Two species of Aora are now known from the British Isles: A gracilis (Bate) which is widely distributed, and A. spinicornis Afonso, recently discovered in Lough Hyne, Co. Cork, and herein reported for the first time from these waters. This latter species has a Lusitanian distribution (Azores, Canaries, Mediterranean) and may occur in south-western England and Wales, but has been confused previously with A.gracilis (Bate). Both species have been described and figured by Myers (1973, 1982) and do not require further detailed analysis. However, since both species are now known to occur in these waters and are not both treated by Lincoln's widely used monograph, the two species are figured here as entire specimens (for details of appendages including mouthparts see Myers, 1982) and briefly diagnosed, and a key is provided to facilitate their identification by British and Irish workers.

Many size-selective predators switch their diet during ontogeny. At the White Sea, the adult moonsnails Amauropsis islandica feed mostly on Macoma balthica clams. The diet of juveniles was largely unknown. We conducted a field survey and a caging experiment to find out if juvenile moonsnails can prey on Hydrobia ulvae, and whether they prefer this snail to their usual prey. Live molluscs and their intact or perforated shells were collected from 34 sediment cores. We exposed the single-prey cages with 50 Macoma (MP) or 50 Hydrobia (HP) together with five Amauropsis juveniles, as well as the cages where both prey species were in a 25:25 proportion (HMP). While live Hydrobia was more abundant in the natural assemblages, Amauropsis preferred Macoma, as indicated by proportions of perforated shells. The caging experiment produced similar results. Per capita Macoma consumption rate was significantly higher than Hydrobia consumption rate (6.4 ± 0.5 mg day−1 ind.−1vs. 1.4±0.2 mg day−1 ind.−1 in MP and HP respectively). Prey consumption rates in the single-prey treatments were higher than in mixed-prey cages regardless of prey species. Different mechanisms explain this variation: for Hydrobia it is a consequence of the dietary shift, while for Macoma it reflects the ‘floor’ effect in HMP cages, where virtually all Macoma had been drilled by the end of exposure term. While Macoma is the preferable prey of young Amauropsis, Hydrobia can supplement the diet of juveniles when Macoma is scarce in certain locations.

To determine the group structure of Sotalia guianensis on the coast of Paraná State, two bays, Baía de Paranaguá and Baía de Guaratuba, were surveyed between March 1999 and February 2000 and between July 2002 and June 2003 respectively. The heterogeneity of the studied areas was considered a relevant factor, therefore these areas were sectored and each sector was investigated independently. The surveys were carried out through boat line transects and all the animals were registered, even those localized between two transects. The records were taken for the quantity of groups as well as for the amount of individuals in each group and, whenever possible, the individuals were classified as calves or adults. The data were treated both separately and comparatively between the two bays and amongst the sectors of each bay. In Baía de Paranaguá, 735 individuals were registered, divided into 253 groups which varied from 2 to 37 individuals for an average of 2.9 individuals per group. Most of the groups presented a family formation (59.29%) and were observed during the morning. The individuals that were clearly identified as calves represented 24% of the total (176 individuals), adults 55% (405 individuals) and 21% (154 individuals) were impossible to determine. In Baía de Guaratuba, only 32 S. guianensis individuals were observed and distributed into 14 groups for an average of 2.13 individuals per group. These groups varied from 2 to 6 individuals mostly in family formations (50%). The same quantity of individuals and groups was observed during different periods of the day. Of the 32 sampled individuals, 25 (78%) were adults, only one was a calf (3%) and 6 (19%) were undetermined.

Sixty-eight tides were sampled consecutively to study the retention of fish larvae transported into estuaries. The experiment was conducted at Beaufort Inlet, North Carolina, USA, in March 1996. The inlet is primarily tide-driven and meteorological forcing has a minor influence. Four species of winter-spawning fish were abundant in the samples: Atlantic menhaden, Brevoortia tyrannus; Atlantic croaker, Micropogonias undulatus; spot, Leiostomus xanthurus; and pinfish, Lagodon rhomboides. Across-shore winds significantly affected flow and physico-chemical characteristics of the water. Across-shore winds also positively influenced the larval retention provided larvae did not present a clear tidal rhythm of vertical migration within the water column and that winds pushed in the water during flood tides. The retention of larvae migrating vertically in respect to the direction of the flow was independent of meteorological forcing of the water.

All polymastiid sponges displaying ornamented exotyles are reviewed and their morphological affinities are reconsidered. The study embraces all known species of Proteleia, Sphaerotylus, Trachyteleia and Tylexocladus as well as several species of Polymastia. A new genus, Koltunia, is established for the Antarctic species Proteleia burtoni based on the unique shape of distal ornamentations of its giant exotyles and on the absence of a spicule palisade in its cortex, a rare feature among the polymastiids. Three new species of Sphaerotylus are described – S. renoufi from the British Isles, S. strobilis from South Africa and S. tjalfei from West Greenland. Transfer of one New Zealand species from Polymastia to Proteleia and of one Chilean species from Polymastia to Sphaerotylus is proposed. The present study provides a background for future integrative phylogenetic analyses based on comprehensive molecular and morphological datasets which should reveal the natural relationships between the polymastiid taxa.

A new mechanism of demosponge spicule formation was recognized during taxonomic studies of bioeroding sponges (Porifera: Demospongiae: Clionidae). To date different spicule types have been explained by matching structures to their organic matrix, the axial thread. Bulbous structures, however, do not have an organic counterpart. Immature spicules of Cliona tinctoria and Pione caesia have irregular, rough heads. Higher magnification during scanning electron microscopy shows that silica granules are deposited regionally to form bulbs. Later silica secretion smoothens the bulb surface. Silica deposition in form of granules rather than in layers appears to be a structuring tool in tylostyles.

A description is given of the commonest sublittoral algae and sessile animals found on rock at Stoke Point Reef and at the E. Blackstone rock near Dartmouth to a maximum depth of 28 m. The E. Blackstone fauna resembled that of Plymouth Sound. The marked change which has been found is ascribed to the greater turbidity of the water near Dartmouth and the increased shelter from wave action.

Perhaps the world's best-known cetacean, the bottlenose dolphin shows considerable variation in behaviour between and within populations in relation to differences in natural and anthropogenic conditions. Drivers of behavioural variation need to be identified to understand the dynamics of wild dolphin populations. Little research has been published on the bottlenose dolphin population found in the Southern Adriatic Sea. Using a set of spatial, temporal and social predictors, we aimed to investigate what variables are related to the behaviour of an under-studied population of bottlenose dolphins along the coastline of Montenegro. We present the results of a year-long study monitoring the behaviour of bottlenose dolphins along coastal Montenegro. We considered the effect of topography, seasonality and group size. A large proportion of travelling (55%) small groups (mean 4, range 1–9) in shallow waters (<50 m) was observed. We showed that seasonality alone explained behaviour best, with surface-feeding and socializing-resting increasing in autumn and winter. Group size was found to be a result of behavioural choice. We suggest seasonal changes in environmental conditions and anthropogenic pressure may explain the recorded behavioural pattern. This research points to the necessity of increased collaboration in the region to help understand complex patterns in behaviour and habitat use of local dolphin populations if effective conservation measures are to be developed.

In addition to the spicules typically produced by sponges, about twenty hypercalcified species belonging to both classes Demospongiae and Calcispongiae secrete a massive basal calcareous skeleton composed of calcite or aragonite. Skeletal growth rates and growth mechanisms are still poorly known in those hypercalcified Calcispongiae. In situ calcein staining experimentation on the Mediterranean calcisponge Petrobiona massiliana revealed a mean annual growth rate of the massive skeleton of 236 µm/y (±90). Scanning electron microscopy (SEM) revealed that some spicules are entrapped within the massive skeleton (a solid mass forming apical crests with multidirectional growth axes) during its formation. Whole actines were observed within the massive skeleton of fractured specimens, indicating that they do not dissolve after entrapping. Calcein incorporation bands seen through epifluorescence microscopy and SEM morphological observations of the skeletal surface revealed cone shaped protuberances corresponding to active growth areas. A spatially discontinuous growth was highlighted, but the annual growth rates were similar at the tip of crests and at the bottom of depressions separating them. The skeleton of P. massiliana is composed of magnesium calcite with strontium as the main trace element. Significant differences in skeletal chemistry of specimens collected in different Mediterranean locations revealed a possible temperature dependence of Mg/Ca. Although such temperature signature exists in the massive skeleton of P. massiliana, its use as an accurate environmental recorder is limited by several factors including multidirectional and spatially discontinuous growth.

Investigations into the relations between plankton and herring, using the Hardy Plankton Indicator, were carried out by this department during the years 1930 to 1933 (Hardy, Henderson, Lucas and Fraser, 1936). In planning this work Professor Hardy made provision for obtaininginformation, when possible, on weather conditions and on the occurrence of organisms which would not be caught in the plankton samples. Information on the presence of jelly-fish, was specifically requested. Skippers of drifters using the Indicator were asked to fill in a printed labelfor each disc giving details of ship, date, time, position and catch, and the following sentence was printed at the foot of the label:— “ Any further notes regarding state ofweather, sea, presence of jelly-fish, or any unusual conditions may be written on the back.” Since the details of date, position, catch, etc., were essential for the success of the Indicator experiments, only these were definitely asked for, and skippers were left to supply further information if they had time to do so. Much more exact and extensive information regarding the presence of jelly-fish arid other organisms could have been obtained if the enquiry had been confined to these points, and it is hoped that this may be done in the future, either from thisdepartment or by other workers. Russell (1935, b), in stressing the importance of plankton organisms as indicators of different hydrological conditions, says “it is especially valuableto watch for any correlations between the presence or absence of certain plankton animals with that of fish and larger swimming animals.”

Alepocephalus bairdii is a deep sea fish caught but discarded by semi-industrial fisheries from the north-east Atlantic Ocean. Reproductive features were investigated on 448 females of 29–93 cm standard length (SL) captured over 2 y (December 1995–December 1997) at 800–1280 m off the west coast of the British Isles. The first maturity of females was determined at L50=55 cm SL. A well-defined spawning period could not be determined in this species; a batch spawner characterized by an indeterminate annual fecundity. Absolute batch fecundity was estimated between 458 and 7049 oocytes per female 63–88 cm SL.

The present paper is the first scanning electron microscope (SEM) description of a protonymphon larva of an Ammotheidae. The morphology of the first larval instar of Achelia assimilis is described in detail and illustrated for the first time. The morphological characters are compared to previous larval descriptions of other pycnogonid species. The larvae are integrated into Bain's classification of larval types within the pycnogonids (Bain, 2003a) as a ‘typical protonymphon’. Larvae were obtained from ovigerous males, caught in Punta Huinay, Huinay, Chile and analysed with light microscope and SEM. Descriptions of pycnogonid protonymphons at a species-specific level in the future will contribute to a deeper understanding of larval pycnogonid taxonomy at the level of differential diagnoses.

Normal females of the mud shrimp, Upogebia major, have a pair of pleopods on the first abdominal segment, while normal males do not. We have investigated nine populations in the Seto-Inland Sea, Japan, and found morphological disorders on the first abdominal segments of both males and females. In males, the first pleopods occurred. Morphology and arrangement of these additional pleopods were classified into four types. The pleopods of Types M-1 and M-2 were similar in structure to those of normal females. These males could be considered as de-masculinized individuals, and the occurrence of males with these morphological disorders showed local variation: while their frequency was high in two specific sites in Kasaoka Inlet (11.5% in Site 6 and 5.5% in Site 7), it was less than 3.5% in other sites. Other types had abnormal additional appendages similar to the walking legs (pereiopods) (Type M-3) or biramous leaf-like pleopods (Type M-4), but their frequency was extremely low (only 3 out of 1558 males inspected). Morphological disorders in males (Types M-1 and M-2) occurred independently of gonadal development, and did not affect the sexual characteristics as revealed by analyses of allometric growth and gonadal index. In females, morphological disorders were classified into five types: incomplete first pleopods (Type F-1); lack of the first pleopods (Type F-2 and F-3); transformation into the pereiopod-like pleopods (Type F-4); and biramous leaf-like pleopods (Type F-5). The frequency of Types 1–3 was especially high in Site 6 in Kasaoka Inlet (24.4%), but was less than 9.4% in other sites. A feature was that cuticular lesions often co-occurred with the morphological disorders. Possible causal factors of these abnormalities are discussed.

In situ grazing activity of mesoplanktonic copepods was investigated by the fluorometric method during an algal spring bloom in a zone of oyster farming in Marennes-Oléron Bay. The grazing activity of copepods was overall higher during the night than during the day for three species (Temora longicornis, Paracalanus parvus and Acartia clausi), but peaks also appeared during the day for all of them. Individual ingestion rates and daily rations were higher during neap tide (low suspended particulate matter (SPM) concentrations) than during spring tide (high SPM concentrations). During ebb tide (when SPM concentrations were the lowest) the feeding activity of T. longicornis, P. parvus and A. clausi was significantly negatively correlated with algal concentration. Our work suggests that during the algal spring bloom in the farming area of Marennes-Oléron Bay the pressure exerted by mesoplanktonic copepods on the algal stock was very low, as a consequence of: (i) high algal concentrations in the field (resuspension and high phytoplanktonic production); (ii) low ingestion rates when high algal concentrations were observed. The likely ingestion of non-fluorescent particles by copepods is discussed.

In this study we report a new record of a cryptogenic polychaete from southern Africa. The species was found inhabiting sand tubes in intertidal sand flats in the Knysna Estuary on the southern coast of South Africa. Morphological comparisons using light and scanning electron microscopy showed extensive taxonomic similarities with Dipolydora socialis described from other localities and from museum vouchers. In addition, 18S rRNA and COI barcodes were generated for the species. Genetic analysis of the assembled polydorid dataset corroborated the morphological data in delineating the species as a taxonomic unit with >99% genetic similarity to available sequences of D. socialis in the GenBank database. Dipolydora socialis has been reported as having a widespread distribution, and since it can reside within tubes associated with fouling communities or as a shell borer, several vectors may have been responsible for its global spread and introduction to southern Africa. Finally, considering the many cryptic complexes that are currently being uncovered within polychaetes, including spionids, future taxonomic studies should incorporate additional genetic data from other regions of the world to determine whether D. socialis may also be part of a larger species complex.

In this paper a rare case of a double swordfish mortal attack against an adult blue shark (Prionace glauca) is reported. A female blue shark, with a total length of 3 m, was found stranded along the southern Sicilian coast (Strait of Sicily, Mediterranean Sea) on 30 May 2018. The analysis of this carcass revealed the presence of two swordfish bill fragments, impaled in the shark head; the former on the snout, the latter near the eye. The results of anatomical and computed tomography scanning analysis on the head of the blue shark showed that the larger bill fragment (19.7 cm) probably determined the death of this animal, having been impaled in a vital point, just behind the right eye. The analysis of both these events and other similar swordfish-shark interactions reported in the literature makes possible the hypothesis that young swordfish specimens put in place a precise defensive strategy against their potential predators or competitors, aimed at hitting vulnerable and vital points and delivering a mortal blow.

Improved understanding of the occurrence and spatio-temporal distribution of bivalve larvae holds significant benefits for ecological studies, shellfisheries management and aquaculture. Morphological methods for identification have proved difficult to develop because of the small size of these larvae and similarities in their shape and colour. Molecular methods based on DNA extraction can confirm the presence of a species in a plankton sample, but without sample sorting and individual larval analysis, provide no estimate of larval abundance and are incapable of providing an estimate of larval growth rate. Fluorescence in situ hybridization (FISH) using species-specific DNA probes has the potential to resolve these issues. However, utilization of this technique is constrained by the strong autofluorescence, common in marine larvae. Here we evaluate the effect of eight different fixatives on the autofluorescence intensity of bivalve larvae using fluorescein isothiocyanate (FITC) and Cy3 filters. In addition, fifteen autofluorescence reduction treatments were evaluated and their compatibility with FISH assessed. Relative to fresh larvae, chemically fixed larvae had significantly higher autofluorescence in both filter sets. Larvae preserved by freezing at –80°C exhibited no significant increase in autofluorescence over a 3-year period. Autofluorescence levels were generally lower with the FITC filter set than the Cy3 filter set. For archived larvae preserved in modified saline ethanol and exhibiting fixative-induced autofluorescence, the autofluorescence intensity could be reduced to 20–30% with saturated Sudan Black B and to 30–40% with Chemicon™. Both of these autofluorescence reduction treatments were compatible with subsequent FISH protocols using a FITC-labelled probe.

Parathemisto gaudichaudi (Guerin) exists in a range of morphological forms comprising the compressa extreme, in which the fifth pereopod (P5) is only slightly greater in length than the sixth pereopod (P6), the bispinosa extreme, in which P5 is about twice the length of P6, and a complete range of intermediate forms. Other features such as the shape of the carpus and merus of the third and fourth pereopods and the shape of the uropod peduncles also vary between the two extremes. In an earlier paper on the taxonomy of the genus (Sheader & Evans, 1974) it was noted that specimens of Parathemisto gaudichaudi kept in the laboratory could moult towards either of these extremes.