Biofilm-dwelling ciliates are a primary component of a biofilm, and play an important role in the functioning of microbial food webs by mediating carbon and energy flux into benthos from plankton. The carbon flux of biofilm-dwelling ciliates was studied at different trophic-functional levels within the colonization process in coastal waters of the Yellow Sea, northern China from May to June 2015. Samples were collected, using a glass slide method, at the time intervals of 1, 3, 7, 10, 14, 21 and 28 days from depths of 1 and 3 m. The carbon biomass of both total ciliates and all trophic-functional groups increased following the logistic growth curve model. During the whole colonization period, the bacterivores and non-selectives were generally the primary contributor to the carbon flux in young samples (<14 days), while the algivores and raptors predominated mature samples (14–28 days) at both depths. In terms of mature samples, however, the non-selectives and algivores were the primary contributors at a depth of 1 m, while the raptors accounted for primary contributions to the carbon flux at a depth of 3 m. Although the times to 50% maximum carbon biomasses were generally ranged 24 days at both depths, the maximum carbon biomasses were significantly higher at depth of 3 m than at 1 m. These results may provide useful information for ecological research on carbon flux from plankton to benthos in marine ecosystems.

Existing population studies of deep-sea amphipods have focused on species that inhabit deep-sea vent or trench environments but few cosmopolitan species have been studied. Here we provide new insight into the life history and population ecology of the pan-oceanic scavenging amphipod Paralicella caperesca and discuss the influence of nutrient-rich submarine canyon environments on the growth and reproduction of this species. Data were collected through the dissection and measurement of 2997 P. caperesca from 14 samples taken from abyssal plains, continental slopes and submarine canyons in the North-East Atlantic. Sexual dimorphism was less pronounced than observed for other scavenging amphipod species but females were significantly larger and had shorter antennae than males. The size of oostegites in female P. caperesca varied considerably within size classes, ovaries contained a relatively large number of oocytes, and no empty ovaries were observed. These factors, in combination with absence of mature females, suggest that P. caperesca practices semelparity, a reproductive strategy that complements the feeding strategy of this obligate necrophage. Five male and seven female size-grouped cohorts were identified for P. caperesca. Cohorts from deep-sea submarine canyon populations showed consistently larger mean total body lengths than non-canyon cohorts. Individuals from canyon samples also expressed sexual characteristics at smaller sizes than non-canyon individuals. We hypothesize that these trends are indicative of nutrient-mediated growth, maturation, and reproduction in P. caperesca. The species is able to grow and reproduce relatively quickly in response to increased nutrient input in canyon environments and therefore dominates scavenging amphipod assemblages.

Experimental removals of the dominant canopy-forming kelp Ecklonia radiata were conducted at two sites on rocky walls in New Zealand and monitored for approximately 1.5 years. We hypothesized that the removal of the E. radiata canopy would affect the structure of subcanopy assemblages, such that there would be a reduction in sponge species richness and abundance. Furthermore, we investigated the biological and physical (predictor) variables that best explained variability in sponge assemblages after canopy removal. Canopy removal led to a community dominated by turf algae, which corresponded with a decrease in sponge abundance and richness. Our results suggest that the Ecklonia canopy may positively influence the presence of sponge species such as Crella incrustans; we propose that the canopy may allow its coexistence with turf algae underneath the canopy by altering the light regime and other environmental factors, which may be detrimental for some species. Our results highlight how any loss of canopy-forming species might have negative effects on sponge assemblages, which could affect the energy flow and the overall biodiversity found in these habitats.

Marine organisms possess the capacity to produce a variety of unique and biologically potent natural products for treating human diseases, many of which are currently commercially available or are in advanced clinical trials. Here we provide a short review on progress in the field and discuss a case study of an EU-funded project, PharmaSea, which aims to discover novel products for the treatment of infections, inflammation and neurodegenerative diseases. Research in this sector is opening new doors for harnessing the potential of marine natural products with pharmaceutical properties.

Despite the current global decline in seagrass, sessile epifaunal invertebrates inhabiting seagrass ecosystems, particularly sponges and ascidians, have been poorly studied due to their taxonomic complexity. Understanding patterns of distribution of sessile epifaunal communities in seagrass meadows is an important precursor to determining the processes driving their distribution and species interactions. This study (1) identified the sponge and ascidian assemblage associated with Posidonia australis meadows and (2) determined distributional patterns of these invertebrates at a hierarchy of spatial scales in Jervis Bay, Australia. We used a fully nested design with transects distributed in the seagrass (10s m apart), two sites (100s m apart), and six locations (km apart). Within these transects, we recorded the abundance, volume, diversity and substratum used for attachment by sponges and ascidians. We encountered 20 sponge species and eight ascidian species; they were sporadically distributed in the seagrass meadows with high variability among the transects, sites and locations. A few sponge and ascidian species dominated the assemblage and were widespread across the largest spatial scale sampled. The remaining species were mostly rare and sparsely distributed. Sponges attached to a variety of substrata but most notably shells, P. australis and polychaete tubes. No obligate seagrass species were recorded although three species predominantly used P. australis as a substratum. These sponge species relying heavily on seagrass for their attachment are likely prone to disturbances impacting their host habitat. Examining the response of sessile epifauna to the degradation of their seagrass habitat remains a key challenge for the future.

Harbour seals (Phoca vitulina) and northern elephant seals (Mirounga angustirostris) are the only phocid species found in Mexico. There is evidence that harbour seals at other latitudes exhibit non-migratory behaviour; however, there is lack of knowledge regarding this species' movements in Mexico. In contrast, elephant seal migrations to high latitudes are documented. In order to analyse this behaviour in harbour seals, hair samples (N = 19) were collected from weaned, or nearly weaned, pups on Natividad Island, Baja California (BC), during the 2013 breeding season (February). Lanugo samples (N = 20) were also collected from elephant seal pups on the San Benito Archipelago (60 km north of Natividad) during the same season, providing information on maternal foraging during the last 4–5 months before sampling. Of the two species, BC harbour seals had higher isotope values, reflecting their non-migratory behaviour. These differences may be due to the depleted base values in the higher latitude foraging areas used by northern elephant seals relative to the areas around Natividad frequented by harbour seals. A lower trophic position by elephant seals was considered but taken as an unlikely explanation for this variation. Bayesian analysis confirmed the distinction, with a low overlap value (0.4) and different isotopic spaces (Phoca: 0.5, Mirounga: 1.6). Building upon previous studies of the trophic ecology of the two phocids that inhabit the region, we provide new information by comparing the two species during the same season using the same tissue type sampled from individuals of similar age classes.

When and where marine eels spawn is poorly known even though species such as those of the family Congridae, Muraenidae and Ophichthidae can be caught in continental shelf habitats. The congrid genus Ariosoma includes small continental shelf eel species whose life histories are not yet known. Mature male and female eels of Ariosoma meeki were observed and captured on 17 August 2009 at the surface at night in the western side of the Kuroshio Current in the East China Sea close to new moon, while they were swimming slowly at the surface and exhibiting apparent reproduction-related behaviour. One male and one sex-unidentified eel (seemingly a male based on body shape) were observed to be chasing one larger female with their heads located near her urogenital pore area. The gonads of the female (540 mm) and the male (410 mm) that were caught by a long-handled dip net were in reproductive condition, because some eggs or seminal fluid were released during handling of the two specimens and high gonad-somatic index (GSI) values of 53 in the female and 20 in the male were recorded. This is one of the few cases in which fully ripe reproductive-condition marine eels have been observed or collected and it provides rare information about the spawning location and timing of this eel species.

A prey–predator experimental setup was conducted in a shallow coastal ecosystem characterized by a bare intertidal mudflat to test if benthic biofilm resuspension causing microalgae inputs and carbon export toward nanoflagellates would favour the highest planktonic trophic level (i.e. mesozooplankton) when nutrient concentrations are high in the water column. Mesozooplankton predation and somatic production were studied by comparing the evolution of the prey assemblage (diversity and abundances) in the presence and absence of these predators during 24 h experiments. The results were then statistically analysed according to the cross-calculation method. Biofilm resuspension caused (i) a direct input of benthic microorganisms that had changed prey structure in term of diversity and/or size and (ii) a differential growth ability between prey taxa. Both reasons implied a bottom-up control on both micro- and mesozooplankton. The carbon export toward heterotrophic nanoflagellates favoured pelagic ciliate growth while mesozooplankton benefited from largest diatoms with high growth rates, both benthic and R-strategist pelagic species. Even if these microbial and herbivorous pathways are controlled by benthic inputs, they seemed to be totally disconnected since ciliates represented only a small part of mesozooplankton diet. The sensitivity of mesozooplankton production appeared species-dependent with the most tolerant taxa dominating the zooplankton assemblages. This suggests a role of the intensities and the frequencies of biofilm resuspension on the spatio-temporal structuring of mesozooplankton in macrotidal coastal ecosystems.

Assessing the sensitivity of ectotherms to variability in their environment is a key challenge, especially in the face of rapid warming of the Earth's surface. Comparing the upper temperature limits of species from different regions, at different rates of warming, has recently been developed as a method to estimate the long term sensitivity of shallow marine fauna. This paper presents the first preliminary data from four tropical Ascension Island, five temperate New Zealand and six Antarctic McMurdo Sound species. The slopes and intercepts of these three assemblages fitted within the overall pattern for previously measured assemblages from high temperature tolerance in tropical fauna and a shallow slope, to low temperature tolerance and a steep slope in Antarctic fauna. Despite the tropical oceanic Ascension Island being subject to upwelling events, the fit of the intercept and slope within the overall assemblage pattern suggests that the upwelling is sufficiently predictable for the fauna to have evolved the plasticity to respond. This contrasts with previously analysed species from the Peruvian upwelling region, which had a steeper slope than other temperate fauna. The speed and capacity of faunal assemblages to acclimatize their physiology is likely to determine the shape of the rates of warming relationship, and will be a key mechanism underpinning vulnerability to climate warming.

Members of the tubicolous polychaete family Serpulidae constitute one of the most important groups of marine fouling biota. This paper describes a new species of the serpulid genus Hydroides from dock fouling at Mazatlán (southern Gulf of California), providing information about live colouration and reproductive features. Hydroides dolabrus sp. nov. belongs to a subgroup of species in which verticil spines are equal in size and shape, lack both external and lateral spinules, but have various modifications to their tips. However, Hydroides dolabrus sp. nov. is distinct in having tips of verticil spines pickaxe-shaped, with asymmetrical triangular radially orientated projections: the internal projections are short and point inward the verticil centre, while longer external projections point outward the verticil centre. Like all species of the genus, H. dolabrus sp. nov. is a gonochoristic broadcast spawner lacking sexual dimorphism. A phylogenetic analysis of Hydroides based on COI, 18S and cyt b sequence data reveals that H. dolabrus sp. nov. is genetically distinct from other species of Hydroides for which sequence data are available. The new species is the 11th in the genus described from Mexican waters.

Age and growth of Agassiz's parrotfish Sparisoma frondosum captured off Brazil (Pernambuco) were estimated using sagittal otoliths from 251 specimens. Sex of each specimen was determined and showed that 130 specimens were females (13.1 to 36.8 cm TL) and 121 were males (17.5 to 36.6 cm TL). The otolith marginal increment analysis indicated a single translucent ring formed every year. Parameters of growth curves were derived for the von Bertalanffy (VBGF) and Gompertz models. Based on the Akaike information criterion (AIC), both models were suitable for describing the growth of this species. VBGF parameters were estimated for males L∞ = 39.74 cm TL, K = 0.22, t0 = −1.63 years, females L∞ = 32.38 cm TL, K = 0.44; t0 = −0.23 years; and for the sexes combined L∞ = 33.66 cm TL, K = 0.41, t0 = −0.27 years. The study showed that 55% of individuals were 3 and 4 years of age, with maximal age of 9 years. Mature females (>17.6 cm TL) accounted for 45% of the sample. The age at first maturity for females was 1.6 years. For males the size at first maturity was not determined as immature individuals were not present in the overall sample. Also, primary males (PM) and specimens with gonads undergoing sexual transition were not found. The age structure and growth parameters for S. frondosum are an important contribution to the assessment of the state of exploitation of this species.

A new final fish host (Stromateus brasiliensis) for the digenean parasite Monascus filiformis from the continental shelf of Patagonia Argentina in the South-western Atlantic Ocean is reported. This demersal-pelagic fish (commonly denominated pampanito) is exclusively a jellyfish consumer. It is well known that larval stages of Monascus filiformis mostly use medusae as secondary hosts. Therefore, the pampanito likely acquires this parasite when it predates upon some species of parasitized medusae in the area. This work improves the knowledge about the final hosts of this parasite and infers which species of medusa may be involved in their life cycle.

Coral reef associated marine invertebrates, such as the blue sea star Linckia laevigata, have a life history with two phases: sedentary adults and planktonic larvae. On the one hand it is hypothesised that the long pelagic larval duration facilitates large distance dispersal. On the other hand, complex oceanographic and geographic characteristics of the Visayan seascape could cause isolation of populations. The study aims to investigate the genetic diversity, genetic population structure and gene flow in L. laevigata to reveal connectivity among populations in the Visayas. The analysis is based on partial sequences (626 bp in length) of the mitochondrial cytochrome oxidase I gene (COI) from 124 individuals collected from five localities in the Visayas. A comparative analysis of these populations with populations from the Indo-Malay Archipelago (IMA) published previously is also presented. Genetic diversity was high (h = 0.98, π = 1.6%) and comparable with preceding studies. Analyses of molecular variance (AMOVA) revealed a lack of spatial population differentiation among sample sites in the Visayas (ΦST-value = 0.009; P > 0.05). The lack of genetic population structure indicates high gene flow among populations of L. laevigata in the Visayas. Comparative analysis with data from the previous study indicates high connectivity of the Visayas with the central part of the IMA.

Understanding animal movement patterns is not only important for providing insight into their biology, but is also relevant to conservation planning. However, in aquatic and wide-ranging species such as cetaceans, this is often difficult. The common bottlenose dolphin (Tursiops truncatus) is the most common cetacean in the northern and central Adriatic Sea and has been the focus of long-term studies in some areas. All of the studied local populations show a relatively high degree of site fidelity, but their movements, ranging patterns or connectivity are not well understood. On 24 and 26 April 2014 a single adult bottlenose dolphin was observed and photographed alive off the Slovenian coast. The same individual was found dead on the shores of Goro, Italy, on 5 May 2014, about 130 km from the two sighting locations. The well-marked dorsal fin made the identification straightforward. The dolphin was found freshly dead, suggesting it had died very recently prior to being found. This indicates that the reported movement was a real one, rather than an artefact of currents. Although single cases cannot provide the basis for making population-level inferences, our observation shows that northern Adriatic bottlenose dolphins can make substantial movements in short periods of time and suggests that such movements could be more common than currently documented. Comparisons among photo-ID catalogues and stranding events can be highly informative, as they can provide useful information with implications for the cross-border conservation of mobile marine predators.

We present some additional information to Acritagasyllis longichaetosus Lucas, San Martín & Sikorski 2010, the only representative of an enigmatic genus of Syllidae from subpolar areas off Norway, based on two newly found specimens and one male and another female stolons. The armature of the pharynx was incorrectly interpreted in the original description, having in fact a trepan instead of a single pharyngeal tooth as originally described. The reproductive stolons are herein described for the first time. With this new information we performed a maximum parsimony phylogenetic analysis that placed this genus within the subfamily Autolytinae, despite its peculiar morphological characteristics. For this reason, we propose a new diagnosis to the genus Acritagasyllis as well as a modified diagnosis of the subfamily Autolytinae.

In this study we revise the current knowledge on the biodiversity and distribution of the Class Homoscleromorpha in the Tropical Western Atlantic (TWA). Twenty-seven species are currently recognized in the TWA, belonging to the genera Oscarella (O. nathaliae), Plakortis (P. angulospiculatus, P. dariae, P. edwardsi, P. halichondrioides, P. insularis, P. microrhabdifera, P. myrae, P. petrupaulensis, P. potiguarensis, P. simplex, P. spinalis, P. zyggompha), Plakinastrella (P. globularis, P. microspiculifera, P. onkodes, P. stinapa), Plakina (P. coerulea, P. elisa, P. jamaicensis, P. monolopha, P. tetralopha, P. trilopha, P. versatilis), Corticium (C. diamantense, C. quadripartitum) and Tetralophophora (T. mesoamericana). Three of these ‘species’ are cosmopolitan and in fact represent complexes of cryptic species: Plakina monolopha, P. trilopha and Plakortis simplex. All other 24 species reported are TWA endemics. Only four species are found both in the Caribbean and in Brazil: Plakortis angulospiculatus, P. halichondrioides, Plakinastrella microspiculifera and P. onkodes, but these may also be species complexes. Seven species are Brazilian endemics: Plakina coerulea, Plakinastrella globularis, Plakortis insularis, P. microrhabdifera, P. petrupaulensis, P. potiguarensis and P. spinalis. Thirteen species are restricted to the Tropical North-western Atlantic: Corticium diamantense, C. quadripartitum, Oscarella nathaliae, Plakina elisa, P. jamaicensis, P. tetralopha, P. versatilis, Plakortis dariae, P. edwardsi, P. myrae, P. zyggompha, Plakinastrella stinapa and Tetralophophora mesoamericana. The Greater Antilles is the richest ecoregion, with 12 species reported. Only the Guianan ecoregion has no records of Homoscleromorpha. Several undescribed species of Oscarella and Plakina are also known from the TWA. We estimate that the biodiversity of Homoscleromorpha in the TWA is at least twice as high than currently known.

In the present work we describe nine saccular otolith morphometric indices (circularity, rectangularity, aspect ratio, percentage of the otolith surface occupied by the sulcus, percentage of the sulcus length occupied by the cauda length and ostium length, otolith length relative to the length of the fish, rostrum aspect ratio and percentage of the rostrum length occupied by the otolith length) of 41 species of the Tripterygiidae family collected mainly from New Zealand, Australia, Chile, South Africa, Mediterranean Sea and North America. The principal component of analysis showed that the indices that best explain the variability between species were related to sulcus and rostrum morphometry. According to cluster analysis, otolith morphometry could reflect the diversity of microenvironments for some genera such as Notoclinops and Forsterygion, while this does not happen to genera like Enneapterygius and Ruanoho. The discriminant analysis showed that the species Helcogrammoides cunninghami, Karalepis stewarti, Lepidoblennius haplodactylus, Notoclinus compressus, Ucla xenogrammus can be discriminated by using the morphometric indices. Two new indices related to the sulcus that were of great value for the discrimination of these species are described for the first time. This information will be a useful tool for palaeontological, taxonomic and trophic ecology studies.

The diet and feeding habits of the striped seabream, Lithognathus mormyrus, from the Gulf of Gabes were investigated by examining the stomach contents of 1221 specimens ranging from 9.7 cm to 24.1 cm total length (and 11.2 g to 158.1 g in weight). Specimens were collected from commercial catches between September 2005 and August 2007. Of the total number of examined stomachs, 1115 were empty (Index of vacuity = 91.3%). This percentage varied significantly over the year, attaining a maximum in winter (95.77%) and summer (95.79%) and, a minimum in autumn (82.25%). Eight higher taxonomic groups were identified (teleosts, crustaceans, molluscs, echinoderms, annelids, spongia and plantae). Crustaceans were the most important prey taxa, constituting 84.6% of the total IRI. Other taxa, such as teleosts, and molluscs were of secondary importance. Significant differences in the diet were observed in relation to season. The estimated trophic level was 3.63 ± 0.59 for the whole population of L. mormyrus of the Gulf of Gabes. Based on the composition of its diet, this species may be considered to be an omnivorous fish with a preference for animal material and showed a specialist feeding strategy.

Within the English Channel, the common cuttlefish Sepia officinalis is a semelparous species for which a 2-year life cycle was exclusively described in the 1980s. In the 1990s, new research indicated that whilst a 2-year life cycle was still evident for females and the large majority of males, a small proportion of males were actually maturing at only 1 year of age. Since 1980, the interest of French and UK fishers for this resource has increased and it is nowadays one of the most important demersal species of the area and is considered to be fully exploited. From the start of the 20th century, fishing effort and sea surface temperatures have increased in the English Channel and have probably impacted the life history traits of S. officinalis. A 2-year sampling programme was undertaken at French landing sites of the English Channel during the reproduction season in 2010 and 2011 to estimate if the proportion of 1-year-old mature animals has changed. Age determination was carried out by coupling polymodal decomposition and lipofuscin measurement. Size-at-maturity for each year and each sex was estimated by fitting a binomial error GLM. Results highlight that a variable percentage of males and females belonging to the first cohort are mature and that size-at-maturity was lower than that observed in the 1990s. Finally, different parameters, such as temperature and fishing pressure are explored to discuss changes in life history traits suggesting that cuttlefish could be an indicator of the temperature regime shift in the English Channel.

The present study tests hypotheses about sexual dimorphism in body size and morphology versus differential mating behaviours of three male ontogenetic stages (typus, intermedius and robustus morphotypes) of the hingebeak shrimp Rhynchocinetes durbanensis Gordon using canonical discriminant analysis. There is strong sexual dimorphism in this species, in that robustus morphotypes are greater in size and with larger appendages (extended third maxillipeds and major [first] chelipeds) than females. As typus males grow bigger in size, their third maxillipeds and major chelipeds become proportionately larger than those of females, and the numbers of corneous spines on the terminal segment of the maxillipeds are reduced. Although there is no sexual dimorphism in body size between typus and intermedius males and females, the robustus males are often substantially larger than females. During mating and spermatophore transfer, all male morphotypes performed similar behaviours (touching, overlapping and holding), but only intermedius and robustus morphotypes appeared to fertilize the broods of the females successfully. Robustus males were faster in approaching as well as mating with receptive females than subordinate males. When mating with robustus males, females spawned more quickly than after mating with typus and intermedius males. Additionally, the time taken for spermatophore transfer by typus males was longer. Rejection by females during the initial approach by typus males often resulted in unsuccessful spermatophore attachment. Results of this study suggest a dominance hierarchy in R. durbanensis similar to certain other rhynchocinetid species in which females appear to prefer mating with the larger robustus males.