Free-living nematodes were investigated in the Mar Piccolo of Taranto (Ionian Sea), a semi-enclosed basin of strategic importance for its complex productive infrastructure but in need of remediation due to the alarming amounts of heavy metals and synthetic organic contaminants in the sediments. Abundance, genera composition, biodiversity and trophic traits of nematodes were related to the gradual transition from marine to more brackish conditions and to the varying levels of contaminants in different sub-areas of the basin. Nematodes were more abundant and diverse at the most marine site while low numbers and diversity characterized the most contaminated station. Going towards the innermost part of the basin, gradually increasing values of abundance and biodiversity were observed although the assemblage was susceptible to the organic enrichment caused by mussel farms. The use of nematodes as ecological indicators mirrored the response of the assemblage to the main patterns acting in the basin (High/Good scores at the most marine site and Poor/Bad scores at the most contaminated station), giving a clear indication of environmental quality to stakeholders/authority that can contribute to address remediation actions in contaminated sediments.

Olindias spp. medusae are found worldwide in sublittoral tropical and sub-tropical coastal regions; their occurrence near shore can result in human envenomation events. While behaviour of medusae and human contact with medusae has been documented for the genus, the hydroid (polyp) phase of the Olindias life cycle has eluded investigators for over a century. Given the recent debate among public media and scientific communities that jellyfish blooms are increasing worldwide, there is a growing urgency to understand how and why jellyfish populations bloom. In order to understand jellyfish population dynamics, the asexual benthic phase must be studied to determine when, where, and how juvenile medusae are produced. In this study, husbandry management strategies, including the creation of artificial habitat for Olindias formosus medusae in aquaria were developed to encourage spawning and larval settlement. The resultant hydroid colony of Olindias formosus was discovered in November of 2012, utilizing the natural fluorescence of the medusa as a detection method. A description of the hydroid and early medusa stage is presented. These techniques provide a basis for locating in situ the benthic hydroid phases within this genus and other fluorescent medusae, the discovery of which may lead to a better understanding of the causative factors for jellyfish blooms.

The functional morphology of Pinna nobilis is described, with special reference to the uniquely pinnid pallial organ, the similarly unique buccal (formerly pallial) gland, the stomach and its contents. The pallial gland produces sulphuric acid which as well as functioning as a shell cleaning swab may be involved in prey capture. The buccal gland discharging into the oesophagus has proteolytic digestive functions while the stomach is adapted for the reception and digestion of captured, mucous-bound, mesozooplanktonic and epi- and endo-benthic, prey items. Pinna nobilis is thus not simply either an accidental or incidental predator of such species but is opportunistic. The buccal glands and stomachs of other Pinnidae are not so specialized as in P. nobilis, possibly indicating that in the particular, oligotrophic, environment of the Mediterranean and Adriatic Seas, and in which it is endemic, P. nobilis has, in addition to being a typical ctenidial suspension feeder, become an opportunistic predator. Although the deep sea representatives of the Septibranchia (Anomalodesmata) and Propeamussidae are obligate predators, this is the first record of any bivalve functioning as an opportunistic predator with unique morphological adaptations to facilitate this.

The limpet Patella aspera Röding, 1798, is a native species from the Macaronesian region whose fishing is regulated. The early life of limpets, including the settlement process, is poorly known thus far. The current study evaluated different substrates to induce settlement in P. aspera, including microalgae strains (Halamphora coffeaeformis, Navicula incerta and Pavlova sp.) and crustose coralline algae (CCA) obtained from limpet shells. The results showed that gametes obtained by dissection and matured artificially using alkalinized seawater baths can produce viable larvae able to metamorphose to juveniles. Feeding was not required during larval development, suggesting lecithotrophy. Early postlarvae were identified by the shedding of the velum, and juveniles were identified by teleoconch and active grazing behaviour. The presence of CCA shortened the timing for settlement and increased the ratio of juveniles. The type and abundance of CCA can influence settlement success. Moreover, the results suggested that settlement and metamorphosis in true limpets (Patellogastropoda) might be triggered by a two-step mechanism, i.e. a first cue influencing the shift between swimming and crawling activity and a second cue determining settlement and metamorphosis to early postlarvae and juveniles.

Introductions of predators can have strong effects on native ecosystems and knowledge of the prey size selection of invasive predators is pivotal to understand their impact on native prey and intraguild competitors. Here, we investigated the prey size selection of two invasive crabs (Hemigrapsus sanguineus and Hemigrapsus takanoi) recently invading European coasts and compared them with native shore crabs (Carcinus maenas) which are known to feed on similar prey species. In laboratory experiments, we offered different size classes of native blue mussels (Mytilus edulis) to different size classes of the crab species in an effort to identify the respective prey size preferences and potential overlap in prey size range of native and invasive crabs. In all three species, the preferred prey size increased with crab size reflecting general predator–prey size relationships. Prey size preference did not differ among the crab species, i.e. crabs showed similar mussel size preference in relation to carapace width. Given that additional morphological measurements showed that both of the invasive crab species have much larger claws relative to their body size compared with the native species, this finding was surprising and may relate to differential claw morphologies or structural strength. These results suggest that the invasive crabs exert predation pressure on the same size classes of native mussels as the native crabs, with potential effects on mussel population dynamics due to the high densities of the invaders. In addition, the overlap in prey size range is likely to result in resource competition between invasive and native crabs.

The composition and structure of sublittoral faunal assemblages inhabiting soft bottoms (15–72 m depth) within the Marine Protected Area ‘Acantilados y Fondos Marinos de Calahonda-Castell de Ferro’ in southern Spain (North Alboran Sea, Mediterranean) have been studied in relation to sediment and water column variables. Three assemblages were identified and corresponded to mixed bottom, unstable bottom and coastal detritic bottom assemblages, based on Pérès & Picard's (1964) benthic classification. A total of 14,318 individuals were collected and 218 species identified, molluscs being the best represented group (141 species). Species richness displayed significant differences with depth and transect, with the highest values observed in the medium to very fine sand and muddy bottoms with bioclasts located at the shallowest sampling stations. The presence of some rare and poorly known invertebrates that are scarce in other areas of the Mediterranean Sea is remarkable, such as the crustacean decapods Bythocaris cosmetops and Pagurus mbizi, Atlantic species with no records in the Mediterranean Sea, and the bathyal molluscs Poromya granulata and Alvania testae, collected at shallow depths. The spatial distribution of faunal assemblages was mainly related to depth and percentage of gravel and clay according to the canonical correspondence analysis. The geographic location of the area, the heterogeneity of soft bottoms and the presence of upwellings in the area may favour the high biodiversity found in the studied soft bottoms. This study increases the scarce knowledge of the circalittoral fauna of sedimentary habitats of the Alboran Sea, providing a baseline for the management of this interesting SCI and for the EU Marine Strategy Framework Directive.

Flounders grew much more slowly in 1944 than during the previous 2 years. From October 1943 to October 1944 their mean size increased from 7·9 cm., 6·8 g., to 12·7 cm., 23·6 g., an increment which was if anything smaller than under normal conditions. The reason for the reduction in growth rate is attributed to the increasingly unfavourable hydrographic conditions resulting from the prolonged closure of the dam, in particular to the high H2S concentration, the high pH and the low oxygen concentration of the water.

In the autumn of 1944 the sluice gate of the dam was opened for several months. In 1945/46 the growth of stock III flounders was very rapid. They reached a mean size of 32·3 cm., 409 g., in March 1946 and 36·8 cm., 580 g., in March/April 1947. Native flounders reached a mean size of 30·6 cm., 353 g., in 2 years.

1. Observations are given on the vertical distribution of Sagitta elegans and S. setosa in the daytime.

2. An account is given of the seasonal abundance of both species of Sagitta throughout the year as shown by collections made with oblique hauls with the 2-metre stramin ring-trawl and hauls with a bottom plankton net.

3. An attempt is made to piece together as much as possible of the life-stories and habits of Sagitta in offshore waters off Plymouth on the basis of these and previous observations.

Coral reefs have experienced extensive degradation across the world over the last 50 years as a result of a variety of stressors operating at a range of spatial and temporal scales. In order to assess whether declines are continuing, or if reefs are recovering, detailed baseline information is required from across wide spatial scales. Unfortunately, for some regions this information is not readily available, making future reef trajectories difficult to determine. Here we characterized the current benthic community state for coral reefs in the Wakatobi region of Indonesia, one of the most biodiverse marine regions in the world. We surveyed 10 reef sites (5, 10 and 15 m depth) to explore spatial variation in coral reef benthic communities and provide a detailed baseline. Previous data (2002–2011) were available for coral, sponges, algae and soft coral at six of our study sites. Using this information, we determined if any changes had occurred in dominance of these benthic groups. We found that benthic assemblage composition differed significantly over relatively small spatial scales (2–10 km) and hard coral cover was highly variable, ranging from 7–48% (average 19.5% ± 1.5 SE). While coral cover appears to have declined at all sites where data were available since 2002, we found little evidence for widespread increases in other benthic groups or regime shifts. Our study provides a comprehensive baseline dataset for the region that can be used in the future to determine rates of change in benthic communities.

The sulphonium compound dimethylsulphoniopropionate (DMSP) is commonly found in temperate green macroalgae. To examine taxonomic and regional and local geographical patterns of DMSP production in Australasian algae, I collected 30 species of green algae from 14 sites in three regions, eastern Australia, Tasmania, Australia, and the North Island of New Zealand. The distribution of DMSP content was similar to that seen from other areas of the world. DMSP was found in high concentrations in Ulva and Codium spp. It tended to be undetectable or in lower concentrations in other members of the orders Bryopsidales and Cladophorales. There was no evidence for differences in concentrations among the three regions in the genera Codium and Ulva; however, the invasive subspecies of Codium fragile, C. fragile ssp. tomentosoides, had significantly higher concentrations of DMSP than the non-invasive subspecies. The herbivorous sea slug Elysia maoria had whole body concentrations that were not significantly different from those of its host alga C. fragile ssp. tomentosoides. The distribution patterns of DMSP in Codium spp. do not support the hypothesis that DMSP is used as an antioxidant in this genus. Based on the data collected here and previous reports from the literature, I speculate that one function of DMSP in these algae may be to deter herbivores.

It is only within comparatively recent times that it has been proved that the otoliths and scales of certain Teleostean fish can be used for the determination of their age.

Rings of growth, as they are called, are produced on these structures, and it is by counting the number that the age is ascertained, in much the same way as the approximate age of a tree may be determined by counting the annual rings.

Most fertile individuals of the apodid sea cucumber Polycheira rufescens, living in the intertidal zone near Iso Marine Station in southern Kyushu, Japan, spawned on day one and two before every full and new moon in the period from the second half of July until August or October from 1983 to 1989, the month differing in different years. Synchronous spawning associated with the same phases of the moon was also observed at Sakurajima Marine Station near Iso in 1991. Individuals ready to spawn were divided into four sexual types: two sorts of hermaphroditic males with small or larger growing oocytes and males and females. Further investigation revealed that some individuals changed from male to female or from female back to male in the two week interval between spawnings. Moreover synchronous gametogenesis occurred in association with sex changes throughout the breeding season, the period from initiation of spermatogonia proliferation to spermatozoa release was three weeks, and the period from initiation of oocyte growth to egg shedding was about five weeks.

The oceanic scyphomedusa Pelagia noctiluca (Forskål) was exceptionally abundant in the coastal waters of Devon and Cornwall in the year 1966. Very young stages were taken only in the months of October, December, January and early February, indicating that the medusa has a restricted breeding season.

Spatial distribution patterns of microzooplankton (0.055–0.3 mm) biomass and abundance were studied in relation to the hydrographic situation and the local flow field in the waters off Ampère and Senghor, two shallow seamounts in the subtropical and tropical NE Atlantic, in comparison with unaffected open ocean reference sites. Ampère was sampled during November/December 2010 and Senghor during December 2011 and February 2013. The study includes taxonomic composition, abundance of meroplanktonic larvae and an estimation of the respiratory carbon demand. Biomass (dry weight) standing stocks of microzooplankton in the upper 100 m ranged between 30–120 mg m−2 over Ampère and 140–260 mg m−2 over Senghor Seamount, corresponding to 33 and 24% of the total zooplankton (0.055–20 mm). Highest total abundance was always found in the upper 50 m with numbers of 1070–5060 Ind m−3 at Ampère and 5050–20,000 Ind m−3 at Senghor with microzooplankton contributing 70–95%. Zooplankton accumulated mainly at the thermocline coincident with the deep fluorescence maximum and was ascertained by food supply rather than by oxygen limitation. The microzooplankton contribution to the total respiratory carbon demand was ~50% in the subtropical waters off Ampère and ~30% at Senghor, reflecting the important role of microzooplankton in the waters of the NE Atlantic subtropical gyre. Clear evidence of local seamount effects resulting in enhanced microzooplankton biomass compared with the unaffected reference sites were not detected. However, we confirmed Senghor as a hotspot for meroplanktonic larvae, suggesting a retention potential that results in significantly enhanced larval abundance in the seamount waters as compared with the open ocean.

The present work reports the existence of extended parental care in a hermit crab species of the genus Calcinus. The species shows a high energetic investment in egg production, only producing one to six large-sized eggs. The larval development is extremely abbreviated, with the larvae hatching at an advanced zoeal stage, a rather uncommon feature among marine and non-symbiotic decapods. The sequential moults end in a glaucothoe-type larval stage that is retained inside the female's host gastropod shell, probably in complete lecithotrophy. The high maternal reproductive investment displayed by this species is certainly maximized through the retention of juveniles until they enter a suitable gastropod shell, since it considerably reduces the chances of intra- or interspecific predation.

Surveys of the plankton at a depth of 10 m in the western English Channel have been carried out at monthly intervals from 1958 onwards using Continuous Plankton Recorders to provide data on annual fluctuations in abundance of the plankton. Interpretation of these results has been attempted by empirical associations with environmental factors (salinity, sea-surface temperature, radiation, atmospheric pressure patterns, wind speed and current strength). Principal component analysis has been used to extract the main patterns of change and correlation analysis for assessing the relationship between the plankton and the environmental factors. There are complex relationships between the plankton and all environmental factors, supporting previous conclusions that the long-term changes are mediated through interaction between the plankton and the climate. Spectral analysis showed long-term trends and shorter cycles of six and three to four years in both the biological and physical elements, indicating that changes in the western Channel are responding to changes in climate over a much wider area

The morphology and infraciliature of an endoparasitic ciliate, Boveria labialis, isolated from respiratory trees of the sea cucumber, Apostichopus japonicus, were investigated using living observation and silver impregnation methods. Based on the present and previous studies, an improved diagnosis is supplied: marine Boveria, size in vivo about 30–100×15–30 μm, body slender and flask-shaped, with a protruding lobe measuring 5–15 μm in length; one ovoid macronucleus and one micronucleus; single contractile vacuole positioned in posterior 1¼ of body length; 17–26 somatic kineties; paroral membrane and membranelle 2 forming a double anticlockwise spiral of nearly two turns.

The ormer, Haliotis tuberculata L. is a greatly prized species in the Channel Isles. Since the original survey of the ormer population of Guernsey and the subsequent tagging experiments (Forster, 1962, 1967), periodical short visits to the island have been made to investigate the stocks of ormers, especially in areas fished by divers; in 1968 and 1974 visits were also made to Jersey. These surveys were all made at the request of the local Sea Fisheries Committee. In this paper we seek to bring together those aspects of the results which are of scientific interest and to discuss the role of various factors which may have affected the ormer populations particularly that of changes in temperature over the last hundred years. The reproductive biology of this species has recently been reported on by Hayashi (1980).

For studying community structure and biodiversity of macrofauna, seasonal samplings were carried out along three different depths (5, 15 and 30 m) in four transects (12 stations) at Noor coast during 2005. Four higher taxa were determined. Polychaeta was the dominant group comprising 96.61 of the total individuals, followed by Bivalvia 1.35%, Oligochaeta 1.15% and Amphipoda 0.87%. Of the six encountered species, the polychaete, Streblospio gynobranchiata accounted for 84.95 of the total population. Also, Tubificoides fraseri was observed in the Caspian Sea for the first time. During this study, density of macrofauna increased with depths, total organic matter and percentage of silt–clay. The highest density was obtained in winter and the lowest was observed in summer. Maximum diversity, richness, and evenness were obtained, 0.91, 1.05 and 0.88, respectively. Also, multivariate analysis separated differences of density between seasons and depths.

Fatty acid profiles and carbon (δ13C) and nitrogen (δ15N) stable isotope markers were used to identify the diet of amphioxus in subtropical Hong Kong waters, and to evaluate the role of co-occurring Branchiostoma belcheri and B. malayanum in trophic transfer, in coastal ecosystems. The present results showed that while amphioxus is generally regarded as a filter feeder, total particulate matter in the water column might not be the main food supply. The diet of amphioxus could be traced to comprise a wide range of food sources, from microbes and microplankton to microalgae, based on the stable isotope analysis. Results of fatty acid profile analysis also revealed contributions from dinoflagellates, zooplankton, detritus and bacteria, and minor contribution from diatoms and fungi in the diet of amphioxus in Hong Kong waters. The use of fatty acid and stable isotope analyses further proved that amphioxus can, not only capture and partition such a different size-range of food particles during their feeding, but also assimilate most of them into their body tissue. The present findings suggested that amphioxus may play an important role in marine food webs by transferring microbial production to higher trophic levels through utilizing microbes in seawater as food.