The continued development of the aquaculture industry is contributing to the proliferation of artificial structures in the marine environment. Observations of seaweed farms (infrastructure and biomass) suggest they act as a habitat for associated species. Seaweed farms differ from other forms of artificial infrastructure as the material deployed already has marine organisms (i.e. culture species) growing on it. This ‘priming’ of ropes with juvenile sporophytes may affect future development of communities by facilitating colonizing species or suppressing competitors. We call this process ‘ecological priming’: the provision of a biological platform that influences the successional development of specific communities. The communities that developed on ropes primed with Alaria esculenta individuals were compared with unprimed ropes to assess the ecological priming effect, at a commercial kelp farm in south-west Ireland. Species richness increased over two cultivation seasons and species composition was consistent between years, with distinct communities developing on primed and unprimed treatments. Timing of species occurrence on primed ropes was predictable with no predictable pattern occurring on unprimed ropes. Multivariate tests indicated distinct communities between treatments, with suppression of other algal species and potential facilitation of some species that have a particular association with A. esculenta on primed ropes. Communities from primed holdfasts contained a lower diversity of algal species compared with unprimed communities. Cultivated kelp holdfasts represent a habitat for distinct assemblages that reflect ecological priming of the substratum.

Iheyaspira bathycodon sp. nov. is described from the Von Damm Vent Field on the world's deepest spreading centre, the Mid-Cayman Spreading Centre (MCSC), Caribbean, at 2300 m depth. The new species is defined and illustrated from 11 specimens, with brief notes on habitat and known distribution. Molecular phylogenetic data from partial COI mDNA, 16S rDNA and nuclear 18S rDNA regions are used to analyse the species’ phylogenetic position and its morphology is compared with previously described skeneid and vent taxa. The new species is distinguished from the most closely allied vent species, Iheyaspira lequios Okutani, Sasaki & Tsuchida, 2000 by morphological differences in radula diagnosis and appendage structure of the head-foot. Iheyaspira bathycodon sp. nov. is the tenth turbinid to be described from a hydrothermal-vent environment and the second species to be named from recently discovered hydrothermal vents on the MCSC. Determining the faunal composition of assemblages at the vent fields of the MCSC will help to elucidate the vent biogeography of the region.

All the specimens of Autolytus prolifer (O. F. Müller) described here were gathered from colonies of the hydroid Obelia flabellata Hincks, growing on pebbles in a shallow creek in the intertidal zone of the Chalkwell mud flats, on the north side of the Thames estuary. The syllid was found to be very plentiful on this hydroid, living in semi-transparent tubes attached to the stem, but was not found elsewhere.

The specimens agree well with previous descriptions of Autolytus prolifer in the number and arrangement of the pharyngeal teeth, and in the chaetae; but some of the other anatomical features show similarities with other species of Autolytus Grube.

The southern shores of the English Channel have long been famous for the wealth of their Tunicate fauna, having furnished material in abundance for the classical researches of Milne-Edwards, Giard, and Lacaze-Duthiers. The Channel Islands also have been repeatedly visited by English zoologists, and have amply supplied those among them who have been in search of Tunicate treasures. Probably the peculiar tidal conditions of this part of the Channel are especially favourable to a rich development of littoral forms; but, as the work of Montagu, Couch, Clark, Alder, Gosse, Cocks, Bate, and Norman sufficiently testifies, the Devon and Cornish coasts of England can lay claim to an almost equally luxuriant shore fauna, the rocky bays and long sheltered estuaries being especially wealthy in this respect. During my residence at Plymouth I found that the Tunicata were among the best represented groups of the fauna, and, as I devoted considerable attention to the search for rare or new, as well as for well-known forms, I trust that a classified report upon the local representatives of the group will not be without its usefulness to other investigators.

During the summer of 1911 I conducted at the Plymouth Biological Station a series of experiments on the living active gas-gland associated with the bladder of certain marine fish, the results of which are recorded in a paper published in the Anatomischer Anzeiger for 1911 (Bd. XL, p. 225). Whilst so employed I incidentally made some observations on the structure and mode of action of the “oval” in fishes, and since my conclusions differ in several particulars from those of Nusbaum and Eeis (Bull. Acad. d. Sciences Gracovie, 1905, p. 778; Anatomischer Anzeiger, Bd. XXXI, 1907, p. 169), I think it as well to put them on record. Most of my observations were made on the Pollack. If a weight be attached to this fish so as to cause the gas-gland (oxygen gland) to become active and to pump oxygen into the bladder, it will be found that the oval strongly contracts, so as to prevent the additional gas forced into the bladder from escaping into the blood. The oval, it may be mentioned, is a large oval area usually situated in the dorsal posterior wall of the bladder. It differs from the rest of the bladder wall in that it alone is permeable to the contained gases, and, like the ductus pneumaticus in Physostomi, permits their escape when the conditions require it. In the Pollack the oval is normally widely open and is invisible to the naked eye, but on the gas-gland being caused to become active in an unusual degree, the oval becomes strongly contracted and is then a very conspicuous structure inside the bladder. This contraction of the oval is of course effected by muscles, and the result of it is to cause the thin-walled permeable area to become more or less completely shut off from the general bladder cavity, the walls of which, as just mentioned, are impermeable.

Data obtained during the cruises of the s.ss. Huxley and Oithona in the years 1903 to 1906 indicated a general seasonal movement of water into and out of the mouth of the English Channel. It was found that in the autumn, somewhat sooner or later and to a greater or less extent each year, water, of the high salt content characteristic of the open Atlantic in the north of the Bay of Biscay and to the south-west of the English Channel, began to move in a north-easterly direction into the mouth of the English Channel, extending in a tongue along the centre of the Channel and into the Irish Channel, which is characterised by water of lesser salt content.

This general movement of relatively high salinity water continued during the winter until the spring or early summer, when water of lesser salinity moved southward from the Irish Channel across the mouth past Ushant, and to some extent into the English Channel; the condition in August being that water of relatively high salinity which had entered the Channel during the winter months was cut off from Atlantic water of equal salinity by a less saline water-mass extending south from the Irish Channel.

These general movements have been deduced from the data collected during the cruises in February, May, August, and November. To accurately depict the changing conditions and follow the movement of the water year by year would require frequent observations, more or less simultaneous, over a wide area—a condition of perfection which in practice could not be obtained without the use of several ships working almost continuously and in conjunction.

Methods of filtration and storage of sea-water samples intended for silicate analysis have been investigated. The desirability in some circumstances of filtering water samples before analysis has been demonstrated. The behaviour of three recommended methods for the analysis of silicate in sea water has been compared by inter-calibration studies.

A new species of Paraseison (Rotifera: Seisonacea: Seisonidae) is described from the eastern Pacific Ocean off the coast of California. Female and male specimens of the new species were attached inside the carapace of the leptostracan crustacean Nebalia hessleri, collected at 19 m depth in La Jolla Canyon. This recording represents the first properly identified and described species of Seisonacea for the American coasts. It is furthermore the second known species of the genus Paraseison, which until now included the species P. annulatus only, reported for the Mediterranean Sea and European west Atlantic coast. The new species was diagnosed mostly by its species-specific trophi morphology and in particular by the shape of its fulcrum. Paraseison kisfaludyi sp. nov. is the fourth described species of the order Seisonacea, which accommodates also Seison nebaliae and the recently described S. africanus, all of which live attached to species in the leptostracan genus Nebalia. Even though the Seisonacea are placed in a crucial position within the phylum and may constitute the link between rotifers and other platyzoans, this taxon has in many respects been neglected in morphological studies. Herein we provide new information on the group's taxonomy, morphology and distribution, which will be useful for future phylogenetic and zoogeographical studies.

The current study investigated basic biological features for two co-occurring shore crabs Pachygrapsus marmoratus and P. transversus in the eastern Mediterranean Sea. Differences in population structure, reproductive periods and settlement patterns were studied along the coast of Lebanon. Sizes of sampled individuals ranged from 4 to 37 mm carapace width (CW) for P. marmoratus and from 3.5 to 24 mm CW for P. transversus. Males were larger than females in both species, each of them exhibiting different size frequency distributions. Both male and female proportions were similar for P. marmoratus while males dominated the population of P. transversus. Fecundity and egg sizes were higher in P. marmoratus and fecundity was directly related to body size for the two crabs. Size structures differed between studied locations showing size restrictions for specific size-classes. Females from both species remained ovigerous for about 5 months, with P. transversus (May–August) started 1 month after P. marmoratus. Larger sized females displayed higher fecundities. The recruitment of juveniles lasted 5 months for both P. marmoratus (December–May) and P. transversus (November–April). Our results showed that niche partitioning occurred between the two species, where P. marmoratus starts incubating earlier than P. transversus while young of the year of the latter settle earlier on the reefs, taking advantage of convenient seawater temperatures and thus minimizing competition. This study shed some light on the populations of grapsid crabs living in the eastern Mediterranean and provided baseline information on the biology and ecology of the two congeneric shore crabs and their interactions.

The franciscana dolphin (Pontoporia blainvillei) is a small coastal dolphin endemic to the south-western Atlantic Ocean. Incidental captures in fishing gillnets is possibly the greatest conservation concern for this species, and occurs within most of its geographical distribution. The aim of this paper is to determine the biological parameters of franciscana dolphin by-caught from artisanal coastal fisheries of the southern Buenos Aires province, Argentina. Between 2003 and 2009, carcasses of 54 incidentally captured franciscanas were collected. The age, sexual and physical maturity and body condition of each specimen was determined. The sex-ratio of the by-caught dolphins did not differ from parity and, consistent with other areas, juveniles younger than 4 yr old were captured in higher proportion (69%). In addition, 74% of the entangled animals were sexually immature and 85% physically immature. Sexually immature dolphins were predominant in the spring, a period which coincides with the breeding season. An assessment of the body condition of captured franciscanas suggests that entanglements were not associated with a disease or physiological disorder. The results presented here are important to assess the impact of artisanal fisheries on the population of franciscana dolphins in the southernmost area of its distribution.

Adapting to the bathypelagic habitat imposes serious challenges for taxa that originate in shallower depths. We describe a new doliolid that has successfully made the transition into deep water. Nine specimens of Pseudusa bostigrinus have been found at depths between 1164 and 1890 m in three distinct regions of the eastern North Pacific. This new thaliacean has exchanged the typical doliolid body plan for one resembling a craspedote hydromedusa. This adaptation allows it to collect sinking particles by simply directing its large buccal opening upward. The development of a hydromedusa-like velum allows it to trap zooplankton prey and to propel itself with considerable force and control. While carnivory is not unknown in tunicates, this is the first report of a carnivorous doliolid. The endostyle of P. bostigrinus is greatly reduced, there are no ciliated bands, and there is no spiral gland; all evidence that mucus feeding filters have been abandoned by this species. Anatomy, diet, behaviour, and habitat distinguish this doliolid from all others described to date.

The main objectives of this study are the establishment of a detailed description of five semi-submerged and shallow-water marine caves from the Tarkhankut Peninsula (Crimea), their biological characteristics with particular attention to species composition, and the distribution of sponge assemblages in these caves. Three semi-submerged and two submerged caves with lengths of 9–131 m and volumes of 61–3060 m3 have been investigated. All of them are karst-abrasive or karst in origin. In the investigated caves, we inventoried seven sponge species. All were recorded species of Porifera belong to the class Demospongiae and have previously been recorded also in adjacent open sea waters. These species are tolerant to different hydrological conditions, mostly temperature and salinity. Some of them have wide geographic distribution. The species composition of sponges from the shallow water caves of Crimea is quite different from the sponge composition in Mediterranean caves. This could be due to the geographic isolation of the Black Sea and the differences in the hydro-chemical parameters of the milieu (water salinity in Tarkhankut is 18–21‰).

In the North Atlantic, the tubular agglutinated foraminifer Bathysiphon major occurs at bathyal depths off the coasts of North Carolina and north-west Africa. Apart from its large size (up to almost 10 cm long), the most distinctive feature of this species is the appearance of the test wall which has a sooty black outer layer, about 20μm thick, overlying a much thicker layer, pure white in colour and consisting of sponge spicules and small quartz grains. The black layer is composed of irregularly shaped, plate-like particles, 1–25 (xm in size. The nature and composition of these particles has been studied using light and electron microscopy, x-ray microanalysis, electron diffraction analysis and infrared spectroscopy. The particles contain calcium and phosphorous and have electron diffraction patterns and infrared spectra consistent with a hydroxyapatite composition. Minor amounts of iron are probably responsible for their black colour. We believe that this represents the first report of apatite-like (phosphorite) particles occurring in the test of an agglutinated foraminifer. The particles are most likely to originate as phosphorite grains which are agglutinated by the foraminifer, although the possibility of authigenic precipitation cannot be eliminated. The function of the outer black layer is unknown.

Peracarid crustaceans are an important component of the vagile fauna associated with coralline algal beds, which often characterize the infralittoral fringe of tropical rocky shores. Among other variables affecting faunal assemblages, sedimentation, food supply and oxygen concentration within mats or turfs of coralline algae may greatly depend on the exposure to waves. In this study, peracarid assemblages were compared at replicated rocky shores within different levels of wave exposure, along a coastline in south-eastern Brazil. Overall amphipod diversity (11 species) was much higher than tanaidacean diversity (two species). Correlation analyses did not support any biological interactions between amphipods and tanaidaceans. Habitat complexity, while apparently limiting amphipod populations, did not affect tanaidaceans at a local scale. Amphipod abundance, not assemblage structure, was positively affected by wave exposure, probably improving oxygen concentration levels and renewal of food resources. Rather than abundance, which remains fairly stable, exposure to waves determined species identity in tanaidaceans, with Zeuxo coralensis found at exposed shores and Leptochelia aff. dubia found at sheltered shores, except for two L. aff. dubia individuals found at one of the exposed sites. Differences in the supply of sediment and the ability of these species in manipulating grains for tube building may explain such a striking pattern.

This study represents the first comprehensive examination of the distribution and abundance of killer whales (Orcinus orca) in the north-west Atlantic. Based on a collation of sightings data and a multi-year photographic catalogue of killer whales, 836 sighting events have been recorded between 1758 and 2012, with most occurring in the last ten years. Killer whales were most commonly observed during June–September in Newfoundland/Labrador, Canada. Most sightings were made close to shore, although many occurred beyond coastal shelf areas and in water depths in excess of 3000 m. Relatively fewer sightings were recorded on the Scotian Shelf, in the Gulf of St Lawrence or the north-eastern USA, despite appreciable aerial and vessel-based cetacean survey effort. In the north-west Atlantic, killer whales have been sighted both alone and in groups, with group sizes ranging from 2 to 30 whales (rarely more than 15, although an aggregation of 100 was reported 43 years ago). Groups usually comprised 2–6 individuals. Based on photographic records, there are at least 67 identified killer whales in the northwest Atlantic; this is an underestimate, since a large portion of our image collection was not of sufficient quality to be considered in the analysis, and many of the whales do not have easily discernible markings. The discovery curve of newly-identified whales has not plateaued, suggesting that there are more whales to identify. These data allow us to better understand the ecology of these killer whales, and provide a baseline against which population changes and distribution patterns can be assessed.

Rhinoptera steindachneri is a commercially important, medium-sized, pelagic migratory batoid fish with benthic feeding habits. It has been considered a specialized predator that feeds on molluscs as well as benthic ophiurids and arthropods off the Mexican Pacific coast. Most biological aspects of this species in La Paz Bay are unknown, despite its being a commercially important species of conservation interest. Therefore, the aim of this study was to characterize the feeding habits of R. steindachneri based on specimens caught in artisanal fisheries. The stomach contents of 310 specimens (146 females and 164 males) were analysed, all captured from 2013 to 2015. The vacuity index was 97.1%, and the most important prey species were Mysidium spp. and Cylichna spp. Because of the high frequency of empty stomachs recorded, it was not possible to describe with precision the general diet of the species. Three hypotheses were developed to try to explain why this characteristic occurred in this species, ranging from eating habits to physiology and prey digestion and geographic location of the study. However, considering the mechanical process of prey handling of R. steindachneri, several hypotheses were formulated, with the hour of capture, chemical processes and physiology and prey digestion being the most probable to explain this high vacuity index reported in this study.

Feeding, defecation, palp behaviour and motility of the tubicolous annelid, Magelona alleni were observed in a laboratory environment. Both surface deposit, and to a lesser extent, suspension feeding were exhibited, with the ingestion of sand grains, and of smaller amounts of foraminiferans and administered commercially available suspension. Predominantly sand could be seen moving through the gut, resulting in conspicuous defecation, not previously observed in other magelonid species. During this ‘sand expulsion’ behaviour, individuals turned around in a network of branched burrows. The posterior was extended from the burrow and substantial amounts of sand were expelled in a string-like formation, involving mucus. The posterior morphology of M. alleni differs greatly compared with other European magelonid species, in possessing a large terminal anus, likely related to its diet. In contrast to what has been recorded for other magelonids, M. alleni appears predominately non-selective. The current paper adds credence to the idea that multiple feeding modes exist within the family. Tube-lined burrows were observed to be primarily permanent, and motility of the species reduced in comparison to other magelonids. The differences noted between M. alleni and other species is most likely linked to its tubicolous lifestyle. The effect of environmental parameters on observed behaviours is discussed.

Since the mid-1980s, swarms of the rhizostome Rhopilema nomadica have been an annual phenomenon in Israeli Mediterranean coastal waters during the summer months. Despite its annual prominence and the potential impact on food webs and ecosystem services, studies concerning its feeding ecology and its interactions with other biota in the marine food web have not been conducted. During summer 2015 gut contents of 41 R. nomadica were analysed as well as ambient plankton assemblages. More than 60% of the medusae diet was found to consist of microzooplankton <150 μm. Size correlations revealed that larger R. nomadica consumed faster swimming prey while smaller medusae relied more on the slower swimming taxa. The medusan diet reflected most of the ambient plankton taxa, but no statistically significant correlations between the relative abundance in diet and ambient plankton were found. As summer progressed, there was a gradual decrease in both mean medusa bell diameter (from 42.2–16 cm) and integrity of feeding structures. These findings suggest that R. nomadica, at least at the time of its appearance in Israeli coastal waters, may exert less predatory pressure on the plankton than we might otherwise expect.

In 1993, a 100-y return-time flood brought about major hydrological changes in the Vaccarès Lagoon (Rhône Delta, France). Four years after the floods, Gobius niger had disappeared from the lagoon. Only the fall in salinity can explain this change. Reproductive traits in 1993 and 1994 were compared to determine the choices this species takes to improve its fitness in such unfavourable conditions. Evidence suggesting that G. niger is not a sedentary lagoon species is also discussed.

The mojarras (Eucinostomus) are a widespread group of coastal fishes of controversial taxonomy because of similarities in their external morphology. In the present study, we assessed the genetic diversity of species and populations of Eucinostomus using DNA barcodes using a systematic and phylogeographic context. In total, 416 COI sequences of all valid Eucinostomus representatives were analysed based on public databases and collected specimens from the north-eastern coast of Brazil (Western South Atlantic). Several cases of misidentification were detected in the barcode dataset (E. argenteus, E. harengulus, E. gula, E. dowii and E. jonesii) that could account for the taxonomic issues in this genus. In contrast, we identified four molecular operational taxonomic units (MOTUs), with divergence above 2% in the Western Atlantic, that correspond to cryptic forms within E. argenteus, E. harengulus, E. gula and E. melanopterus. These data suggest that Plio-Pleistocene events (rise of the Panama isthmus, Amazonas outflow and sea-level fluctuations) played a major role in the diversification of mojarras. While subtle morphological differences have been used as proxies to discriminate Eucinostomus species, the genetic data proved to be efficient in differentiating them and revealing potentially undescribed taxa. Therefore, we recommend that further taxonomic studies in mojarras should incorporate DNA-based evidence.